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╔═════════════════════════════════╗ ║ ║ ║ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ ║ ║ █ █▀█ █▀█ █ █▀█ █▀█ ▀█▀▀▀ ║ ║ █ █ █ █ █ █ █ █ ║ ║ █ █ █▀█ █▀█ ▀▀█ █▀█ █ ║ ║ █ █ █▄█ █ █ █▄█ █▄█ █ ║ ║ █ ║ ║ █ ║ ║ Version 2.60 ║ ╚═══╦═════════════════════════╦═══╝ ║ ║ ║ Paul E. Traufler ║ ║ 111 Emerald Drive ║ ║ Harvest, Al 35749 ║ ║ (205) 726-5511 ║ ║ ║ ╚═════════════════════════╝ Satellite Tracking Program 15 Janurary, 1991 TRAKSAT (C)opyright 1990,91 By Paul E. Traufler All Rights Reserved ╔══════════════════════════════════════════════════════════════════╗ ║ ║ ║ ** TRAKSAT IS FREE FOR NON-COMMERCIAL USE ONLY. ** ║ ║ ║ ╠══════════════════════════════════════════════════════════════════╣ ║ ║ ║ If you find TRAKSAT useful and would like to use it in a ║ ║ commercial operation please call or write for more information. ║ ║ ║ ╚═══════════════════╗ ╔════════════════════╝ ║ ║ ║ Paul E. Traufler ║ ║ 111 Emerald Drive ║ ║ Harvest, Al. 35749 ║ ║ 205-726-5511 (Work) ║ ║ 205-830-8450 (Home) ║ ║ ║ ╚═════════════════════════╝ ════════════════════════════════════════════════════════════════ **************************************************************** TRAKSAT and its companion files are being distributed as shareware. YOU ARE ENCOURAGED TO SHARE THIS SOFTWARE WITH OTHERS PROVIDED THAT IT IS DISTRIBUTED COMPLETE WITH DOCUMENTATION AND IN UNMODIFIED FORM AND THAT NO FEE OR OTHER CONSIDERATION IS CHARGED OR ACCEPTED. **************************************************************** ════════════════════════════════════════════════════════════════ TRAKSAT makes no warranty of any kind, either express or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose, with respect to this software and accompanying documentation. Paul E. Traufler, author of TRAKSAT, SHALL NOT BE LIABLE FOR ANY DAMAGES (INCLUDING DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION) ARISING OUT OF THE USE OF OR INABILITY TO USE TRAKSAT. TRAKSAT Satellite Tracking Program Page 2 TABLE OF CONTENTS ─────────────────────────────────────────────────────────── INTRODUCTION ........................................... 4 THEORY OF SATELLITE MOTION ............................. 5 HARDWARE REQUIRED TO RUN THE PROGRAM ................... 6 RUNNING THE PROGRAM .................................... 7 CHANGING SATELLITE DATA FILES (MAIN MENU FILE OPTIONS).. 9 READ SATELLITE DATA (MAIN MENU FILE OPTION) ............ 10 USER DEFINED STAR DATA (MAIN MENU FILE OPTION) ......... 12 TRACKING STATIONS (MAIN MENU FILE OPTION) .............. 13 TRAKSAT.CTY CITY DATA FILE ............................. 13 SYSTEM DATE/TIME (MAIN MENU SYSTEM OPTION) ............. 15 REAL-TIME MODE (MAIN MENU TIME OPTION) ................. 16 DELTA-TIME MODE (MAIN MENU TIME OPTION) ................ 16 OUTPUT MODES .......................................... 18 ANALYTICAL SOLUTION (MAIN MENU OUTPUT OPTION) .......... 19 USER DEFINED/ALL SATELLITES ............................ 21 GROUND TRACKS (MAIN MENU OUTPUT OPTION) ................ 23 SUN TERMINATOR ......................................... 23 STAR BACKGROUND (MAIN MENU OUTPUT OPTION) .............. 26 ORTHOGRAPHIC VIEW (MAIN MENU OUTPUT OPTION) ............ 31 TABULAR MODES (MAIN MENU OUTPUT OPTION) ................ 32 BATCH MODE ............................................. 35 VISIBILITY (MAIN MENU VISIBILITY OPTION) ............... 37 MULTI-TRACK MODE (MAIN MENU OUTPUT/MULTI) .............. 38 MULTI-TRACK TABULAR OUTPUT MODE ........................ 41 USER DEFINED SATELLITE PLOTTING COLOR .................. 42 QUITTING THE PROGRAM .................................. 42 NORAD/NASA 2-LINE SATELLITE DATA ....................... 43 WHAT ARE THE MEAN CLASSICAL ELEMENTS ................... 45 MODELS FOR PROPAGATION OF NORAD ELEMENT SETS ........... 50 THE PROPAGATION MODELS ................................. 50 COMPATIBILITY WITH NORAD ELEMENT SETS .................. 51 PROGRAM LIMITATIONS AND ASSUMPTIONS .................... 52 ACCURACY OF TRAKSAT .................................... 55 A BRIEF EDITORIAL ...................................... 57 SPECIAL THANKS ......................................... 58 QUESTIONS AND COMMENTS ................................. 59 FUTURE UPGRADES ........................................ 61 REGISTERED USERS ....................................... 62 OBTAINING NORAD SATELLITE DATA SETS .................... 62 FILES REQUIRED FOR TRAKSAT ............................. 64 PROBLEMS ............................................... 65 BIBLIOGRAPHY ........................................... 66 Trademarks used in this document ─────────────────────────────────────────────────────────────── IBM,PS/2 PC DOS are registered trademarks of International Business Machines Corporation. Microsoft MS, MS-DOS, QuickC, are registered trademarks of Microsoft Corporation. Epson FX,LQ, is a registered trademarks of Epson American Inc.. Hercules is a registered trademark of Hercules Computer Technology. TRAKSAT Satellite Tracking Program Page 3 INTRODUCTION Ever since college I have been interested in satellites and tracking methods. I have often looked up into the night sky and thought, "I know satellites are up there but can I predict when and where to look to see one". I have several small programs to calculate different satellite related quantities but there was not one program available to do all the things I felt a satellite tracking program should do. After several years of working in the aerospace field, I decided that I could take on such a programing task. I started it all with a program called STS, it was geared towards tracking the space shuttle, but used the same basic orbital calculations. STS, version .95, is available on several BBS around the country, see the references at the end of this document. For a first attempt at such a satellite tracking program I was some-what pleased with the results. But I felt there is room for improvement and that is where TRAKSAT steps in. TRAKSAT is a general purpose satellite tracking program, by that I mean any satellite that has a NORAD, NASA 2-Line element set can be used. There are some limitations in the program along with some assumptions, the reader is directed to the section on limits and assumptions for further study. The solution to the satellite motion which is used by TRAKSAT is completely analytic and therefore requires no numerical integration. This makes the program fast, even faster when a coprocessor is used, since the solutions can be evaluated at arbitrarily large, or small, time intervals. The purpose of this program is to provide the user with a means of propagating NORAD element sets in time to obtain tracking information of the space object. TRAKSAT Satellite Tracking Program Page 4 THEORY OF SATELLITE MOTION A complete development of the theory required to predict the position of an artificial satellite about the earth is not presented here because this is not proper place for it. Such a development would require a volume in itself and would be more of a distraction than an aid to the potential user. Only enough of the concepts required for a general understanding plus the final results are given. References to detailed works from which these results are derived are provided for the more than casually interested reader. At the end of the TRAKSAT operating instructions is a brief overview of the fundamentals used in this program and is included to help the reader understand the motion of an artificial satellite about the earth. TRAKSAT Satellite Tracking Program Page 5 HARDWARE REQUIRED TO RUN THE PROGRAM In order to run the program the user will need the following hardware; IBM or compatible PC,XT,AT,PS/2,386, 640K Ram (450K FREE RAM IS REQUIRED), Floppy or Hard Disk, Text mode display (25x80), Hercules, CGA, EGA, or VGA graphics (used for plotting only), Math coprocessor is NOT required for TRAKSAT, (IF A COPROCESSOR IS PRESENT IT WILL BE USED *), Epson FX-80 printer or compatible (for graphic print out only), PC DOS or MS DOS version 3.0 or above. * It should be noted that a coprocessor will be 3 to 4 times faster than the emulator version. If the user plans on using the real-time tracking mode, a coprocessor will "smooth out" the time steps to such a small delta as to appear instantaneously. At any rate the real-time mode runs as fast as the host computer can calculate the data and update the screen. ****************** * IMPORTANT NOTE * ****************** The user will not be able to run TRAKSAT on a 360K floppy drive, The size of the executable and the earth map data plus a satellite data file will simply not fit on the 360K floppy disk. The best solution to the problem would be run TRAKSAT from a hard disk! The prices of hard disks have come down to a point where practically all computers have them. If the user needs a "good reason" to buy a hard disk, perhaps TRAKSAT can convince them to do so. ****************** * IMPORTANT NOTE * ****************** To print out the document, TRAKSAT.DOC use the DOS copy command. The syntax to use would be "COPY TRAKSAT.DOC PRN", without the quotation marks. TRAKSAT Satellite Tracking Program Page 6 RUNNING THE PROGRAM To start TRAKSAT you type "TRAKSAT", without the quotation marks, at the DOS prompt. The opening screen will appear and display the version number of the program. The earth data file will be loaded into memory while displaying the opening screen also. This may slow down the loading time on some slower XT type machines. After the opening screens are displayed the main menu will be displayed next. From the main menu the user can control the program. The main menu will display the current status of the program, i.e., current satellite, output mode, tracking station, etc.. The Status Box will always display the current information that is loaded in memory. This will help the user to identify the modes of operation available in TRAKSAT. The main menu is the core of the program, i.e. from this menu the user can setup satellite data, tracking station data, and output selections. Here is an main menu example; ┌───────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ │ │ │ │ ┌──────────────────┤ CURRENT STATUS BOX ├───────────────────┐│ │ │ Tracking Station = Huntsville, AL Twilight = -12° ││ │ │ Latitude (deg) = 34.7317 Longitude (deg) = -86.5967 ││ │ │ Altitude (m) = 228.60 UTC Offset (hrs) = -6 ││ │ │ Current Satellite = File: NASA748.TXT ││ │ │ Current Output Mode = Ground Track : Single ││ │ │ Current Time Mode = Real Visibility = Optical ││ │ └───────────────────────────────────────────────────────────┘│ └──────────────────────────────────────────────────────────────┘ From the Current Status Box the user can see that no satellite is currently loaded but the tracking station is Huntsville, Al and the default satellite data file is NASA748.TXT. The output mode will be Ground Track using the Real time mode and Optical visibility with a twilight setting of -12°. If the user selects the Output option from the main menu the other options available in TRAKSAT will be displayed. If the user selects a different output mode the Current Status Box will TRAKSAT Satellite Tracking Program Page 7 display that output mode. A full explanation of the options is included in this document but for the most part the user can figure out most of the options with out additional help. ****************** * IMPORTANT NOTE * ****************** Most error messages are displayed for 3 SECONDS, then depending on what the error was, program control will return to the user to correct the problem. (If a user action is required after a error message is displayed the program will instruct the user to press a key.) ****************** * IMPORTANT NOTE * ****************** All of the menu selections can be changed by either the arrow keys, mouse movement, or the first letter of the menu choice. (The left mouse button will select the hi-lighted menu option.) The mouse driver version used in the testing of TRAKSAT was Microsoft 7.03. Several other versions and other mice have been used with no problems also. (The mouse is disabled during any graphics output.) TRAKSAT Satellite Tracking Program Page 8 Main Menu FILE Options The file options from the main menu will allow the user to change tracking stations, satellites, and load user defined star data. Below is an example of the File options. ┌───────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ ┌─────────────────────────┐ │ │ │ Change Satellite File │ │ │ │ Load Satellite Elements │ │ │ ┌──────────│ Read User Star Database │ ├───────────────────┐│ │ │ │ New Tracking Station │wilight = -12° ││ │ │ Latitude │ View Text File │ (deg) = -86.5967 ││ │ │ Altitude └─────────────────────────┘ (hrs) = -5. ││ │ │ Current Satellite = File: NASA748.TXT ││ │ │ Current Output Mode = Ground Track : Single ││ │ │ Current Time Mode = Real Visibility = Optical ││ │ └───────────────────────────────────────────────────────────┘│ └──────────────────────────────────────────────────────────────┘ Change Satellite File For example; if the user would like to change the name of the satellite data file the hi-lighted bar would be placed on the Change Satellite File option. (The user could have pressed the C key and moved the hi-lighted choice directly to the choice.) To select this option press the return (or Enter) key or the left mouse button. The program will display the old satellite data file and prompt the user for the new file name. The displayed file name can be edited using the arrow keys, or mouse to obtain the desired file. After editing the file name the user will press return and the program will look for the file. A message will be displayed if the file is found and an error message will be displayed if the file is not found. The program will not allow the "-" character in a satellite file name. TRAKSAT Satellite Tracking Program Page 9 The screen will appear similar to; ┌────────────────────┌───────────────────────────────┐────────────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │┌──< Satellite Filename >───┐──────────────┐ │ ││ Currently: [NASA748.TXT ] │ellite File │ │ │└───────────────────────────┘lite Elements │ │ │ ┌──────────│ Read User Star Database │ ├───────────────────┐ │ │ │ Tracking │ New Tracking Station │wilight = -12° │ │ │ │ Latitude │ View Text File │ │ │ │ │ Altitude └─────────────────────────┘t (hrs) = -5. │ │ │ │ Current Satellite = File: NASA748.TXT │ │ │ │ Current Output Mode = Ground Tr┌────────────────────────────────┐│ │ │ Current Time Mode = Real │ Satellite data file was found. ││ │ └────────────────────────────────└─┤ Press any key to continue ├──┘│ └─────────────────────────────────────────────────────────────────────────┘ Load Satellite Elements To load a particular satellite into memory the user will select the Load Satellite Elements option. The current satellite name will be displayed for the user to change as required. If a blank search string is entered the program will display all of the satellites in the data file one at a time until one is accepted or the end of file is reached. The Status Box will always display the current satellite in memory. (If the satellite name display is blank that means no satellite has been loaded.) A maximum length of 12 characters is allowed in the search string This program uses the NASA, or NORAD 2-line satellite element data file format to read data into the program, (in this text the use of NORAD refers to NASA 2-Line or NORAD satellite element data sets). For a full explanation of the NASA 2-line satellite element data sets see section; NASA 2-Line Satellite Data. To help the new user a NORAD satellite date file is included with TRAKSAT, see section; Satellite Data Sets. The search method used by the program will locate the first occurrence of what was typed in for a search string when compared to the satellite names, i.e. typing in "mi" could locate the satellite named "Mir". The search is NOT upper/lower case sensitive. If a match is found the full name is displayed and the user is asked to accept this data or read for the next occurrence. If the user selects "No" from this menu the displayed satellite is loaded into memory. Selecting "Yes" will continue the search based on the current search string. TRAKSAT Satellite Tracking Program Page 10 If the user does not know ANY satellite names they can enter a carriage return, (Return or Enter), and ALL of the satellite names will be displayed one at a time. ****************** * IMPORTANT NOTE * ****************** TRAKSAT is limited to the first 4000 satellites in any data file. If the user has more than 4000 satellites in a data file they will need to remove, using a text editor, satellite data sets as to include the desired data set in the 4000 limit. This may not prove to be a limitation for most users as most satellite data sets have less than 150 satellite data sets. If no match is found a error message is displayed and the user will try another match. Reading User Defined Stars TRAKSAT has the data for 58 stars in memory at all times however the user can read a properly formatted star data base into memory also. To load a User Defined Star Data Base the user will select the File option from the main menu and then move the hi-lighted bar to the option; Read User Star Database. The program will first ask the user for a file name of the star data base and then look for the file. If the file is located the program will read in the FIRST 1500 stars into memory. The program will then return to the main menu. The user will have the responsibility to check the user defined star data for duplicates of the TRAKSAT internal star data. (See the section on PROGRAM LIMITATIONS AND ASSUMPTIONS for a list of the internal stars used in TRAKSAT.) See the section on USER DEFINED STAR DATA for the format of the star files. ONCE THE USER DEFINED STAR DATA IS LOADED THE PROGRAM WILL USE THE STAR DATA FOR ALL STAR BACKGROUND PLOTS. ***************************************************************** ** REMEMBER TO USE EPOCH J2000 FOR ANY USER DEFINED STAR DATA. ** ***************************************************************** TRAKSAT Satellite Tracking Program Page 11 The screen will be similar to; ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ ┌─< Star Database Filename >──┐ │ │ │ Currently: [STARS.DAT ] │ │ │ └─────────────────────────────┘ │ │┌──────────│ Read User Star Database │ ├───────────────────┐│ ││ Tracking │ New Tracking Station │wilight = -12° ││ ││ Latitude │ View Text File │ ││ ││ Altitude └─────────────────────────┘t (hrs) = -5. ││ ││ Current Sat┌────────────────────────┐ile: NASA748.TXT ││ ││ Current Out│ Reading User Star Data │ : Single ││ ││ Current Tim└────────────────────────┘lity = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ TRACKING STATIONS The last file option, New Tracking Station, will only need to be run once, unless a different tracking station is used, by the user. The program defaults to using Huntsville, Al. as the tracking station, if the user does not want to use the default option they can select a city from the city data file. The city data file has over 730 of the larger U.S. cities latitude and longitudes in it. The tracking station search works very much like the satellite name search. The user is asked for a search string and the first occurrence is displayed, then the next one and so on, until no more matches are found. If the user accepts a match some additional data is asked for by the program. The altitude above mean sea level in meters and hours from Greenwich are required for the tracking station. (Some examples of the hours from Greenwich; EDT = -4, CDT = -5, EST = -5, CST = -6). If the altitude of the tracking station is not known the user can enter zero with out to much loss in accuracy. If the user can not find a match to the city data then they will need to use a text editor to add the city data in the file TRAKSAT.CTY or use the closest city in the file. Below is an example of the TRAKSAT.CTY file. The format of the tracking station file is; City Name Long. (deg) Lat. (deg). 'Huntsville, AL ',-86.5867,34.7317 TRAKSAT Satellite Tracking Program Page 12 The city name can be up to 20 characters long while the longitude and latitude can be up to 14 characters long. A comma or a space MUST separate the data and the city name MUST be enclosed in single quote marks. The TRAKSAT.CTY file can hold a maximum of 8000 tracking stations in it. The user can enter city data into the TRAKSAT.CTY file in any order but it would be wise to include the data in an alphabetical order by states or country. Below is an example screen for Huntsville, Al.. ┌────────────────┌───────────────────────────────┐───────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │┌──< Tracking Station >──┐┌─< Tracking Station Found In File >─┐│ ││ [Huntsville, AL ] ││ Name: [HUNTSVILLE, AL ] ││ │└────────────────────────┘└────────────────────────────────────┘│ │ ┌──────────│ Read User Star Database │ ├───────────────────┐ │ │ │ Tracking │ New Tracking Station │wilight = -12° │ │ │ │ Latitude │ View Text File │ │ │ │ │ Altitude └─────────────────────────┘t ┌─< Keep Reading? >─┐ │ │ │ Current Satellite = MIR Fi│ Yes │ │ │ │ Current Output Mode = Ground Track │ No │ │ │ │ Current Time Mode = Real Visibil└───────────────────┘ │ │ └───────────────────────────────────────────────────────────┘ │ └────────────────────────────────────────────────────────────────┘ TRAKSAT Satellite Tracking Program Page 13 If the user accepts this city the program will ask for some additional information about the tracking station. The screen will appear similar to; ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ │ │ │ │ │ │┌──────────────────┤ CURRENT STATUS BOX ├───────────────────┐│ ││ Tracking Station = Huntsville, AL Twilight = -12° ││ ││ Latitude┌──< Tracking Station >──┐de (deg) = -86.5967 ││ ││ Altitude│ Altitude (m) [228.6] │set (hrs) = -5. ││ ││ Current │ Hours From UTC [ ] │ File: NASA748.TXT ││ ││ Current │ ie, CDT = -5, CST = -6 │ : Single ││ ││ Current └────────────────────────┘ibility = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ ****************** * IMPORTANT NOTE * ****************** If the tracking station changes from the default values the file TRAKSAT.DEF will hold the last saved tracking station data. While running the program if a new tracking station is selected the user will be asked if the old tracking station data should be overwritten or not. If the user saves the current data then the next time TRAKSAT is run that new data will be the default else the old TRAKSAT.DEF will be used. A text editor can be used to change the TRAKSAT.DEF data also, the user will need to use some caution with this method. The TWO EXCEPTIONS are the multi-track options, see the section on its recommended use (MAIN MENU OUTPUT/MULTI) and the user defined area, see section; Analytical Solution. After the tracking station has been chosen the main menu will appear waiting for the next user choice. TRAKSAT Satellite Tracking Program Page 14 Main Menu System Options The System options can change the system date, time, or both, change the printer type used for output, and set the satellite plotting color. ****************** * IMPORTANT NOTE * ****************** THE SYSTEM HARDWARE CLOCK MAY BE RESET ALSO WITH SOME VERSIONS OF MS-DOS OR PC-DOS. Use some caution with this option. Refer to your DOS manuals to use the time and date functions. The System options screen will appear similar to; ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ ┌────────────────────┐ │ │ │ Set System Date │ │ │ │ Set System Time │ │ │┌───────────────│ Set Both Date/Time │ ├───────────────────┐│ ││ Tracking Stati│ Printer Type │wilight = -12° ││ ││ Latitude (deg)│ Satellite Color │ (deg) = -86.5867 ││ ││ Altitude (m) └────────────────────┘ (hrs) = -5. ││ ││ Current Satellite = MIR File: NASA748.TXT ││ ││ Current Output Mode = Ground Track : Single ││ ││ Current Time Mode = Real Visibility = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ TRAKSAT Satellite Tracking Program Page 15 Main Menu Time Mode Options TRAKSAT can propagate satellites in real-time or "delta-time" modes. (The delta-time mode is starting at some particular date and time using a user defined time increment until a ending time is reached.) To change time modes in TRAKSAT the user can select Time from the main menu. The two time mode options will be displayed. If the real-time mode is chosen the Current Status Box will display Real-Time. The real-time mode will update the screen as fast as the hardware will allow. For an XT class machine with no coprocessor, the update time may be 1 to 2 seconds. An AT class computer with a coprocessor can whip along at about 0.4 seconds per update. The powerful and fast 386 coprocessor equipped machine can sing along at 0.1 seconds per update. The average user will not require this great of detail but it is included for the advanced user. If the user would like to track a satellite from say todays date to some future date, the delta time mode is the choice to use. The basic idea is track from some starting date to some stopping date. If the user selects the Delta-Time mode some additional information will be required. The starting date and time along with the length of the simulation. The time step will also need to be entered. The program will display "defaults" that can be accepted by the user or edited to suit the users needs. As of version 2.55 and above the user can enter starting dates and times before, during, or after the epoch. (A positive time step will still be required.) For example; satellite epoch 19 Oct 1990 at 0 UTC the user could enter 18 Oct 1990 2300 UTC as the starting date/time. It is noted that the maximum length, that is from the starting date to some future time, of the simulation is 99 days 99 hours 99 minutes 99 seconds. An approach most people use with the Delta-Time mode is to pick a 2-3 minute time step and check the output for any passes near the tracking station for that day. Then return back to the Delta-Time mode and use a smaller time step to obtain a better estimate of the satellite visibility. Another method is to use the analytical solution option, see the section on Analytical Solution for more information. ****************** * IMPORTANT NOTE * ****************** The time is read from the system clock, and as such is only as accurate as the setting of this clock. The software date and time can be set before running TRAKSAT, OR the system date and time can be set within TRAKSAT. The System option from the main menu will allow the user to change the system date, time or both. TRAKSAT Satellite Tracking Program Page 16 ****************** * IMPORTANT NOTE * ****************** THE SYSTEM HARDWARE CLOCK MAY BE RESET ALSO IF THE USER HAS MS- DOS VERSION 3.3 AND ABOVE. Use some caution with this option. Refer to your DOS manuals to use the time and date functions. A brief note about tracking satellites. The accuracy of the data is the most important part of the prediction process. NORAD does track some 8000+ objects in orbit around the earth, and maintains a data base of the objects. The earth modeling and perturbations are the most important factors in satellite tracking. This program uses the NORAD element sets mainly because they are available and have reasonably good accuracy. If the user would like to "see" a satellite in the night sky the precision of 1 or 2 seconds is not important, several minutes may not even be that important. This is not to say that the average person can not locate the satellite, it is going to pass over some site sooner or later, its the time of the passing that is of importance. It could be said that if you tell me where to look for the satellite and tell me about when I should be looking for it the chances are it will be spotted. The sky is a big place and it would be almost impossible to locate a satellite without any help from programs such as TRAKSAT. In order to observe satellites the user must do a certain amount of pre-observing work. The best way to determine an evening's viewing would be to run the Analytical Solution and use all of the satellites in a data file. Then exit the program and search the output for any satellites with minimum ranges about 1000 km or less. Most nights several satellites will be visible and meet the users requirements. (Some advanced users may use 2000 km as the minimum range but remember the brightness of these satellites can make them almost invisible.) The next step would be plot out star background maps for the selected satellites, or a tabular output. All the user needs now is to wait until the appointed time and go "hunting" for the satellites. This process only takes a few minutes and can greatly reduce the frustration levels new users may experience. TRAKSAT Satellite Tracking Program Page 17 Main Menu Output Options The main menu Output options will control the output modes available in TRAKSAT. The output modes available will be Analytical Solution, Ground Track, Orthographic, Tabular, and Star Background. (Assuming a single satellite tracking mode is desired. The Multi-Track will only have a Ground Track or Tabular output option.) If the user selects the Output from the main menu the following screen will appear. The user will select either the single track mode or the multi-track modes. ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ ┌──────────────────┐ │ │ │ Single Satellite │ │ │ │ Multi-Satellites │ │ │┌──────────────────┤ C└──────────────────┘──────────────────┐│ ││ Tracking Station = HUNTSVILLE, AL Twilight = -12° ││ ││ Latitude (deg) = 34.7317 Longitude (deg) = -86.5867 ││ ││ Altitude (m) = 228.60 UTC Offset (hrs) = -5. ││ ││ Current Satellite = MIR File: NASA748.TXT ││ ││ Current Output Mode = Ground Track : Single ││ ││ Current Time Mode = Delta Visibility = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ If the user selects the single satellite option the output will be the next choice for the user. TRAKSAT Satellite Tracking Program Page 18 ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ ┌─────────────────────┐ │ │ │ Analytical Solution │ │ │ │ Ground Tracks │ │ │┌──────────────────┤ CUR│ Orthographic View │─────────────┐│ ││ Tracking Station = HUN│ Tabular Output │ ││ ││ Latitude (deg) = 34.│ Star Background │ -86.5867 ││ ││ Altitude (m) = 228│ Batch Mode │ -5. ││ ││ Current Satellite = └─────────────────────┘A748.TXT ││ ││ Current Output Mode = Ground Track : Single ││ ││ Current Time Mode = Delta Visibility = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ Main Menu Output Analytical Solution Options TRAKSAT version 2.00 and above has included a very powerful option, Analytical Rise & Set. Many people have asked "why use this analytical approach ?". Three reasons come to mind speed, speed, and speed! The analytical approach used is a closed form solution to the problem of determining when a satellite can be seen (either LOS or Optical) by a ground tracking station. In effect, this problem usually involves the calculation of the rise-and-set time (UTC) of a given satellite from a specific ground tracking station. In the past, it has been the custom to solve the problem by letting the satellite run through its ephemeris, and checking at each instant to see whether the elevation angle of the satellite was greater than some minimum value. However, by attacking the problem from a different point of view, that is, with the eccentric anomaly taken to be the independent variable, it is possible to obtain a closed-form solution to the satellite visibility problem. Specifically, the closed-form solution is a single transcendental equation in the eccentric anomalies corresponding to a rise-and-set time for a given orbital pass of a satellite. It is more difficult to solve the controlling equation than the standard Keplerian equation. However, the method offers the advantage that the controlling equation is solved only once per orbit period as contrasted with the hundreds of times the Keplerian equation must be solved with the standard step-by-step technique. "How much faster is the analytical solution ?" Several "benchmarks" were run using the same satellite data sets and starting times to determine the speed of each method. If the user selects the Delta Time Mode and then the Analytical Solution the TRAKSAT Satellite Tracking Program Page 19 speed difference will be obvious. ****************** * IMPORTANT NOTE * ****************** The analytical solution methods will use 10 DEGREES AS THE MINIMUM ELEVATION ANGLE that the viewer can "see". In practice that "assumption" is very well founded. The minimum is NOT user selectable in this case. On the machine used for testing (coprocessor installed) the analytical solution runs about 4 seconds per satellite per 24 hours of simulation time vs. the 120 seconds per 24 hours in the delta time mode. (This was on a 386/16 with a 287 coprocessor.) (A 386/33 computer with a 387 can crank out 160 satellites per minute!!!!) Use the analytical solution for "rough" estimates and the delta time mode for the detailed analysis. The term "rough" implies that the analytical solution is not as accurate as the Delta Time mode, and in fact that is true. The error (Delta Time mode vs. Analytical Solution) is usually LESS then 1 minute for predicted rise or set times. (Remember that the analytical solution will display results for a satellite elevation ABOVE 10 degrees.) The error is the price to pay for the speed advantage. ****************** * IMPORTANT NOTE * ****************** The analytical solution DOES INCLUDE THE DRAG EFFECTS in the calculations, (as of TRAKSAT version 2.30). By including the drag effects in the solution a long term prediction can be done without a great loss of accuracy. It has proved helpful for several TRAKSAT users to predict several weeks into the future any visible passes and make a note of the dates. As the date approaches and newer elements become available the user can "improve" the viewing times to finally obtain an accurate prediction of the satellites. Using this approach the user can mark "special" days when a particular satellite should be seen. The analytical solution will save the user from "looking" for satellites that will not be seen, or unfavorable passes. ****************** * IMPORTANT NOTE * ****************** If the user selects the analytical solution AND the OPTICAL visibility test then only satellites with a mean motion of greater than 2.5 revs per day will be calculated. That is any satellite that is "near geosync." will not be calculated. This should NOT be of to great importance to most users as seeing ANY near geosync. satellites is VERY DIFFICULT. The line of sight (LOS) method will still work for the near geosync. satellites. If the user needs to "see" a near geosync. satellite then the single satellite delta time mode OR Batch Mode will be required. TRAKSAT Satellite Tracking Program Page 20 ALL/USER DEFINED SATELLITES The user has the choice with the analytical solution options to select all of the satellites in the data file or some user defined satellites. The default will be to read ALL of the satellites for these options. The user can define his or her "favorite" satellites, up to 25 satellites can be included. The user will need to use a word processor to edit the TRAKSAT.DEF file and add the satellites names to it. The word processor used will need to save the file in PLAIN ASCII format, i.e., NO SPECIAL CONTROL CHARACTERS EXCEPT THE END OF FILE MARKER. The edlin or PC-Write word processors will do the job nicely for the user. An example of the TRAKSAT.DEF file with user defined satellites is included below; column number 123456789012 2447836.50000000 Color = 14 Printer Pins = 9 HUNTSVILLE, AL 34.7317000 273.4033000 228.60 -5 NASA678.TXT Multi-Track Satellite Names Satellite # 1: MIR Satellite # 2: SALYUT 7 Satellite # 3: IRAS Satellite # 4: SEASAT 1 Satellite # 5: EGP Satellite # 6: NOAA 9 User Defined Satellite Names IRAS SALYUT 7 COSMOS 1686 COSMOS 1766 MIR ****************** * IMPORTANT NOTE * ****************** Remember to start the user defined satellite name in column 2. The next 12 characters make up the satellite name, upper or lower case makes no difference. If a user defined satellite is NOT located in the satellite data file a warning message will be displayed. The user defined satellites can be ANY of the satellites included in the data file, however, 25 satellites is the maximum number allowed. If the user has more than 25 satellites then select the All Satellite Data Sets option. That is enough "horn blowing" let us look at an example. Below is and example output from the analytical solution using the screen output option. The visibility method in this example was LOS (line of sight) while the starting date was 4-20-1990 @ 0 UTC hours. The end time was 24 hours. The "header" at the top of the display will show some vital information to the user. The tracking station name and satellite data file name along with the visibility method will be displayed to remind the user of the current settings. TRAKSAT Satellite Tracking Program Page 21 (SCREEN OUTPUT OPTION) TRAKSAT Version 2.00 Analytical Solution Tracking Station: HUNTSVILLE, AL File: NASA678.TXT Visibility: LOS Satellite UTC TIME LOCAL TIME AZIMUTH MAX MIN DURATION DATE HR:MN:SC DATE HR:MN:SC ELE RANGE HR:MN:SC Alouette 1 20Apr90 01:08:32 19Apr90 20:08:32 N TO SE 25 1905 00:10:32 20Apr90 02:54:12 19Apr90 21:54:12 NW TO S 43 1387 00:12:12 Cosmos 398 20Apr90 01:19:02 19Apr90 20:19:02 NW TO E 33 1970 00:16:02 20Apr90 03:34:48 19Apr90 22:34:48 NW TO SE 74 2069 00:26:48 20Apr90 05:54:02 20Apr90 00:54:02 W TO S 21 4272 00:23:02 20Apr90 20:54:16 20Apr90 15:54:16 NW TO N 10 1100 00:01:16 21Apr90 01:27:19 20Apr90 20:27:19 NW TO E 39 1879 00:18:19 Starlette 20Apr90 02:27:41 19Apr90 21:27:41 NW TO E 35 1582 00:13:41 Working ... Press Esc to Quit If the Optical method was selected the header message will display so. ****************** * IMPORTANT NOTE * ****************** The user can NOT stop/start the screen as in the other modes, i.e., pressing Esc will STOP the display and terminate the analytical solution. This method was chosen to avoid inadvertently waiting for the screen to update while in a pause mode. The screen update can be slow on an Optical visibility test and a NON-coprocessor equipped machine. (There may not be any satellites optically visible at all!) If a file output was selected the header placed in the file has the same information as the screen header. Below is an example of the analytical solution file output. (The same times as above were used but this example used the optical visibility test.) ****************** * IMPORTANT NOTE * ****************** The default is to write output to the file TRAKSAT.000. If this file name exists the program will try TRAKSAT.001, TRAKSAT.002... and so on until a new file name is found. If the limit of 999 is reached then the program will use 000 as the extension. (The only options that will use this file method are the Analytical Solution and the Batch Mode file output.) TRAKSAT Satellite Tracking Program Page 22 (FILE OUTPUT OPTION) TRAKSAT Version 2.00 Analytical Solution Tracking Station: HUNTSVILLE, AL [ Optical Visibility ] Satellite UTC TIME LOCAL TIME AZIMUTH MAX MIN DURATION DATE HR:MN:SC DATE HR:MN:SC ELE RANGE HR:MN:SC Alouette 1 20Apr90 02:54:12 19Apr90 21:54:12 NW TO S 43 1387 00:12:12 Cosmos 398 20Apr90 01:19:02 19Apr90 20:19:02 NW TO E 33 1970 00:16:02 20Apr90 03:34:48 19Apr90 22:34:48 NW TO SE 74 2069 00:26:48 21Apr90 01:27:19 20Apr90 20:27:19 NW TO E 39 1879 00:18:19 Starlette 20Apr90 02:27:41 19Apr90 21:27:41 NW TO E 35 1582 00:13:41 20Apr90 02:30:13 19Apr90 21:30:13 NW TO E 55 1241 00:13:13 LAGEOS 20Apr90 04:57:34 19Apr90 23:57:34 NE TO W 47 6830 00:51:34 20Apr90 08:22:09 20Apr90 03:22:09 NE TO NW 27 8006 00:40:09 21Apr90 03:34:44 20Apr90 22:34:44 NE TO SW 70 6108 00:56:44 GPS-0001 20Apr90 02:33:52 19Apr90 21:33:52 W TO SE 65 20491 06:47:52 GPS-0002 20Apr90 05:05:15 20Apr90 00:05:15 NW TO NW 13 24419 01:15:15 GPS-0005 21Apr90 02:37:23 20Apr90 21:37:23 W TO SE 65 20533 06:47:23 GPS-0006 20Apr90 00:16:22 19Apr90 19:16:22 NW TO SW 57 20854 04:27:22 SME 21Apr90 02:15:21 20Apr90 21:15:21 S TO NW 29 812 00:05:21 Salyut 7 20Apr90 09:56:11 20Apr90 04:56:11 SW TO NE 71 413 00:06:11 Cosmos 1383 20Apr90 02:53:40 19Apr90 21:53:40 N TO S 50 1293 00:12:40 IRAS 20Apr90 01:52:33 19Apr90 20:52:33 S TO SW 23 1793 00:08:33 If the user selects the file as the output the screen will display the total number of satellites it will calculate along with the current satellite in memory. Output Ground Track Options If the ground track option is entered the program proceeds to draw a Mercator projection map of the world. The upper left corner is at latitude 90 degrees and longitude -180 degrees, while the lower right corner is latitude -90 degrees and longitude 180 degrees. The grid spacing is 30 degrees for both the latitude and the longitude. A "+" will be plotted for the tracking station coordinates, the coordinates from TRAKSAT.DEF or the currently loaded data. The plotting process may take a minute or two on a slow XT type computer, something under 2 seconds on the particular computer I use. The user will be asked about displaying the sun terminator. The sun terminator is not dependent on the satellite but rather the tracking station. The terminator is plotted based on a zero sun elevation angle. (That is to say the terminator is the line where TRAKSAT Satellite Tracking Program Page 23 the top edge of the sun is "just" below the local horizon.) The terminator is accurate to about 10-15 minutes of actual. The effects of the local horizon and atmospheric refraction can "shift" the terminator a few minutes anyway so great accuracy may not be achieved. The sun is plotted as an "+" in the center of the terminator. This will tell the user on what side of the terminator the tracking station is on. (Daylight or darkness.) The sun terminator will be "REFRESHED" EVERY 4 MINUTES IN EITHER THE REAL OR DELTA TIME MODES. The refresh may take several seconds on the slower machines. (About 20 seconds.) ****************** * IMPORTANT NOTE * ****************** THE SUN TERMINATOR PLOTTING PROCESS MAY TAKE A MINUTE OR SO ON A SLOW XT TYPE COMPUTER, something under 1/3 second on the particular computer I use. The ground track plot is the only option that will display the sun terminator. The file EARTH.DAT contains the world map data, some 8200 vectors in all. This file is compressed to save space and reduce the reading time. (TRAKSAT version 2.10 and up has improved the compression ratio (45%), older versions of the program can NOT be used with this new data file, nor can TRAKSAT use the older data file.) After the world map is displayed the simulation begins. The starting position for the satellite is marked as a yellow filled (if that is the user defined color) circle, this was added to help locate the starting position. The screen will plot the orbital ground trace of the chosen satellite along with other valuable data. The top line will have the UTC date and time, while the second line will have the local date and time displayed. The lower lines will have the tracking data displayed. An example of the output screen would be; -----------------------▌ TRAKSAT Version 2.50 ▐-------------------- | | | UTC 21:37:26.1 Date 12/26/1989 Satellite Name: MIR | | Local 15:37:26.1 Date 12/26/1989 Tracking Station: HUNTSVILLE,AL | | | | (The version number may be different in this display.) | | (no world map drawn in this example) | | | | Lat 45.1635° Azimuth 309.1281° Range 7115.4 Km Ph 129.00 | | Long -175.3926° Elevation -30.1331° Rev # 22120 NOT Visible | | | ----------------------------------------------------------------------- The Lat and Long are the satellite latitude and longitude. The Azimuth and Elevation are as seen from the tracking station, while the Range is the distance from the satellite to the tracking station. The azimuth is always between 0 and 360 degrees with north being TRAKSAT Satellite Tracking Program Page 24 0, east 90 south 180 and so on. The elevation will be always be between -90 and +90 degrees. If the elevation is less than zero the satellite is below the horizon as seen from the tracking station. The Rev # is based on the input data starting revolution number plus the number of revs per day times the days past the epoch date, i.e. the formula; rev = rev_epoch + (mean motion(rev/day) * (epoch date - date). The epoch refers to the NORAD satellite data set, see section; NORAD/NASA 2-Line Satellite Data, for a full explanation of the input data. The Ph is the Phase angle. The phase angle is used for the amateur radio satellites. The phase angle is based on the mean- anomaly, (the position in the orbital plane from the perigee). The mean-anomaly is normally measured from 0 to 360 degrees, however the phase angle is from 0 to 256ths of a circle. The conversion of degrees mean-anomaly to phase angle is; Phase = (mean anomaly (deg))/(360/256). (256ths of circle) It has become common practice with radio amateur satellites to use Mean Anomaly to schedule satellite operations. Satellites commonly change modes or turn on or off at specific places in their orbits, specified by Mean Anomaly. Unfortunately, when used this way, it is common to specify the mean anomaly in units of 256ths of a circle instead of degrees. The phase angle is therefore displayed in units of 256ths of a circle. The last item displayed is based on if the satellite is visible from the tracking station. See main menu Visibility options for a complete description of the methods used by TRAKSAT to test for visibility. ****************** * IMPORTANT NOTE * ****************** To stop the display the user can press any key and the screen will "freeze". The user will need to press any key again to continue the simulation. If the user presses Esc, escape key, the simulation will stop and the user will be returned to the main menu. ****************** * IMPORTANT NOTE * ****************** The ground track will continue until the user stops the simulation by pressing Escape (Esc). After 8-9 ground tracks have been plotted the screen will be "very busy", the user can re-draw the screen by pressing Esc, than pressing Main Menu Run option again. The world map will be drawn again along with the new orbital ground tracks. This will cut down on the screen "clutter". TRAKSAT Satellite Tracking Program Page 25 The user can print out the screen output with the ground track option. To print the output of the screen press "P" or "p", without the quotation marks. The print out may take a minute or so depending on the type of printer being used. The print out will start with the upper right side of the screen. ****************** * IMPORTANT NOTE * ****************** If the user selects any graphic output the program will test for a graphics adapter and based on the type of graphics hardware will select the "highest" graphics mode supported. An example would be; VGA mode 640x480 pixels, EGA mode 640x350 pixels, CGA mode 640x200 pixels, HGC mode 720x348 pixels (Monochrome). ****************** * SPECIAL NOTE * ****************** The Hercules graphics mode requires running the driver MSHERC.COM, this is the driver supplied with several Microsoft programing languages, before using the TRAKSAT program. Type "MSHERC" and then "TRAKSAT" to start the program. (A TRUE Hercules card works with TRAKSAT, some clone cards may NOT.) Do not use a Microsoft mouse AND the Hercules graphics cards together, according to Microsoft, as this may cause some "problems". Any mouse drivers that are installed should be removed before running TRAKSAT with a Hercules card also. **************************************************************** If the user has a computer that is not 100% compatible or the graphic card is not 100% VGA compatible the program can be forced to use the EGA mode. To use this method invoke the program with "TRAKSAT/EGA", without the quotes. This will set the display to EGA modes only and MAY eliminate any graphic problems encountered. NO OTHER GRAPHIC MODES CAN BE SET THIS WAY. **************************************************************** If the hardware does NOT support graphics an error message will be displayed and the program will return to the main menu. All of the text modes will still be available to the user however. Output Star Background Options The star background is a view looking from the tracking site towards the stars. This plot will be useful for producing a "star map" to take outside with you to compare the night sky with the satellite path. If the Star Background option has been chosen the program will ask the user for some additional data. The user can display the TRAKSAT Satellite Tracking Program Page 26 visible star names if so desired. (Only the internal star data names will be displayed, not the user defined star data.) The user will choose what direction to look, i.e., North, East, South, or West. The field of view of the star background is 180 degrees in azimuth and 0 through 90 degrees in elevation. If the user selects North the visible range of the azimuth will be 270 degrees (west) to 90 degrees (east). If the user selects East the visible range of the azimuth will be 0 degrees (north) to 180 degrees (south) with 90 degrees being the center of the screen (due east). The option South will display from 90 degrees (east) to 270 degrees (west). The option for West will display from 180 degrees to 360 degrees with 270 degrees (west) being the center of the screen (due west). As of version 2.60 and above the user can select the star background screen refresh rate. The range of the update is from 5 minutes to 33 minutes. (The recommended setting is 15 minutes.) TRAKSAT Satellite Tracking Program Page 27 An example could be to see a satellite rise out of the west the user would select W, that will display from due south through west to the north. ┌──────────────┌───────────────────────────────┐──────────────┐ │ │ ▀▀█▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ │ │ │ │ █ █▀▀ ▀▀█ █ ▄ █▀▀ ▀▀█ ▀█▀▀▀ │ │ │ │ █ █ █▀█ █▀█ ▀▀█ █▀█ █ │ │ │ │ █ █ █▄█ █ █ █▄█ █▄█ █ │ │ │ │ █ Version 2.50 │ │ │ └───────────────────────────────┘ │ │ │ │ │ │ ┌────────────────┤ M A I N M E N U ├─────────────────┐ │ │ │ File System Time Output Visibility Run Quit │ │ │ └───────────────────────────────────────────────────────┘ │ │ │ │ ┌─< Direction To Look >─┐ │ │ │ North │ │ │┌─────────────│ East │ ├───────────────────┐│ ││ Tracking Sta│ South │ilight = -12° ││ ││ Latitude (de│ West │ (deg) = -86.5867 ││ ││ Altitude (m)└───────────────────────┘ (hrs) = -5. ││ ││ Current Satellite = MIR File: NASA748.TXT ││ ││ Current Output Mode = Tabular Output Screen : Single ││ ││ Current Time Mode = Delta Visibility = Optical ││ │└───────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘ The star background option will display visible stars from a database of 58 navigational stars, the Sun, the planets, and the moon. (Not including any user defined star data.) The term "star background" will be used in this document to mean the 58 navigational stars, the Sun, the planets (not including the earth), and the moon. ****************** * IMPORTANT NOTE * ****************** The star data is internal to TRAKSAT, i.e., there are no provisions for the user to MODIFY THE INTERNAL STAR DATA at this time. Star positions are for Epoch J2000.0, from USNO Floppy Almanac 1988, Version 2.11.88, file STAR1.CAT. HOWEVER THE USER CAN SUPPLY ADDITIONAL STAR DATA TO THE PROGRAM, see the section on USER DEFINED STAR DATA. The option to print out this "star map" (or any other graphic output) is included in TRAKSAT, as of version 1.80 and up. The user will require a Epson FX-80 or compatible printer to use this feature. Again this will prove valuable to the user in determining where and when to look to "see" the satellite, this option will work for LOS or Optical visibility modes. To print out a screen copy the user will only have to press a "P" or "p". After the output is printed the program will continue with the plot. The user can interrupt the printer process by pressing any TRAKSAT Satellite Tracking Program Page 28 key, the printer output will stop and the program will continue. ****************** * IMPORTANT NOTE * ****************** The printer MUST be connected to parallel printer port number 1, LPT1. To stop the printer output the user can press any key. A Epson FX-80 or graphics compatible printer must be used for any output. The print out routines have been tested on several different Epson compatible printers without any problems. Some laser printers can emulate the Epson printers and will produce good results also. THE DEFAULT NUMBER OF PRINTER PINS (9 OR 24) IS READ FROM THE FILE TRAKSAT.DEF. The user can change the "Printer Pins = 9" to "Printer Pins = 24" as required for the printer being used. (The user may try both the 9 and the 24 pin settings to obtain the best output.) ****************** * IMPORTANT NOTE * ****************** If the user has loaded a User Defined Star file the program will plot the internal stars first and then plot the user defined stars next. The user can interrupt the star plotting process by pressing any key during the star plotting process. (Some of the slow XT type computers may take a minute or so when using a large user define star data base.) The user will have the responsibility to check the user defined star data for duplicates of the TRAKSAT internal star data. (See the section on PROGRAM LIMITATIONS AND ASSUMPTIONS for a list of the internal stars used in TRAKSAT.) By default TRAKSAT will display the star names, including the planets and the moon and look west. The user will only need to change these options by typing in the correct response. ***************************************************************** ** REMEMBER TO USE EPOCH J2000 FOR ANY USER DEFINED STAR DATA. ** ***************************************************************** TRAKSAT Satellite Tracking Program Page 29 An example of a star background would be; UTC 14: 2:12.2 Date 3/26/1990 Az 211.3715° Rev# 23519 Local 8: 2:12.2 Date 3/26/1990 El -43.8641° Vis NOT Visible ---------------------------------------------------------------- | Satellite: Mir TRAKSAT 1.85 | | | 75- | | | | O Moon | 60- | | | | EXAMPLE | 45- (NO PLOT SHOWN) | | (This is only an example, the | | DATA displayed is NOT correct) | 30- | | o Venus | | | 15- . Alpharatz | | | | West | ---------------------------------------------------------------- 210 240 270 300 330 The side axis is the elevation while the bottom axis is the azimuth. (Observer coordinates are the only output type at this time). In this example star names were displayed and the option to look west was selected. The "sky track" of the satellite will also be plotted on the screen. The top two lines will display the local and UTC time and dates, azimuth, elevation, rev, and if the satellite is visible (based on the Visibility option setting LOS or Optical). The star map background will remain black even if the sun has risen. (The version number may be different in this display.) ****************** * IMPORTANT NOTE * ****************** If the delta time mode is selected time steps are marked on the screen and labeled for the user. It is recommended that the delta time mode be used for star backgrounds so a "time tag" can be placed on the screen. The real time mode will not place "time tags" on the screen. This approach was used to help reduce screen clutter, i.e., to many time tags. This method was chosen because few people have laptop computers "out in the field" to use for viewing aids. A printed "sky map" generated before the nights viewing will be of much greater use to most people. ****************** * IMPORTANT NOTE * ****************** It is noted that the star background will be refreshed (USER DEFINED) MINUTES, in either delta or real time modes. It is therefore wise to select a starting time about 1 minute PRIOR to TRAKSAT Satellite Tracking Program Page 30 the time of interest and run the program in the delta mode until PAST the time of interest. An example of this would be; Time of interest 11:30:00 UTC, Starting time 11:29:00 UTC, Time span 00:14:00. This will provide the user with the "sky map" from 11:29 to 11:43 UTC and avoid the screen refresh. ****************** * IMPORTANT NOTE * ****************** To stop the display the user can press any key and the screen will "freeze". The user will need to press any key again to continue the simulation. If the user presses ESC, escape key, the simulation will stop and the user will be returned to the main menu. Output Orthographic View If the user selects the Orthographic View main menu a 3-D orthographic projection of the earth and the satellite will be drawn. The perspective will be centered on the tracking station coordinates with the altitude above the earth being set by the semi-major axis of the satellite to view. A small "X" will mark the tracking station coordinates. The grid lines are drawn 10 degrees apart with the orthographic projections. The 3-D graphic will plot the "orbital trace" above the planet, i.e., not the ground trace, WHILE HOLDING THE EARTH STILL. The earth will be non-rotating with the satellite going around it. The close earth satellites (1000 Km altitude and less) will produce a good quality plot while near geosync satellites will display the earth as a small hard to see "ball". The highly eccentric orbits (ecc. > .3) will not display the complete orbital trace due to some limitations of the methods used in TRAKSAT. This should not pose much of a concern to most users. **************************************************************** THE 3-D PROJECTION WILL BE SLOW ON XT TYPE COMPUTERS WITHOUT A COPROCESSOR SO IF THE USER DOES NOT WANT TO WAIT FOR THE COMPLETE EARTH TO PLOT OUT PRESS ANY KEY AND THE EARTH LAND MASS PLOT WILL STOP AND THE SATELLITE VIEW WILL START. (Only the grid lines will be displayed.) **************************************************************** The screen can be stopped and started the same way as any other graphic modes, i.e., any key to freeze and Esc to stop. At this time the altitude above the earth is not a user changed option. If the user would like a polar (either north or south) projection select a new Tracking station from the Main Menu File options and select either the north, south or even the equator tracking station coordinates. TRAKSAT Satellite Tracking Program Page 31 ****************** * IMPORTANT NOTE * ****************** It is recommended that the user edit the TRAKSAT.CTY file and change the first three tracking station coordinates to his or her LOCAL LONGITUDE. The user will answer the questions about tracking station altitude and UTC offset information based on the local conditions. Below is an example of the TRAKSAT.CTY file with the first three "extra" tracking stations included. The format of the tracking station file is; City Name Long. (deg) Lat. (deg). 'North Pole ',-86.5867,90.0 'Equator ',-86.5867,.0 'South Pole ',-86.5867,-90.0 'Rancho Palos Verdes CA ',-118.403334,33.767501 'Calaveras County, CA ',-120.566667,38.15 'Washington (USNO), DC ',-77.06575,38.920556 'Huntsville, AL ',-86.5867,34.7317 The city name can be up to 20 characters long while the longitude and latitude can be up to 14 characters long. A comma or a space MUST separate the data and the city name MUST be enclosed in single quote marks. The TRAKSAT.CTY file can hold a MAXIMUM of 8000 tracking stations in it. (The file included with TRAKSAT has about 740 "cities" in it.) The user can enter city data into the TRAKSAT.CTY file in any order but it would be wise to include the data in a alphabetical order by states or country. Output Tabular Options TRAKSAT can also produce a tabular output of the satellite tracking data, the output is in a text mode not graphics. If the user picks Tabular option, the program will display another menu asking to include the right ascension & declination (Ra & Dec) or the Latitude and Longitude in the output. The output can go to a file or the screen also. The file option output can be edited and printed out by the user if so desired. Below is an example of the screen output without the Ra & Dec; Tracking Station: HUNTSVILLE, AL Satellite: Mir Date Time (UTC) Azim Elev Range Lat Long Rev V HR:MN:Sec Deg Deg Km Deg Deg Thr 25Jan90 01:27:5.550 268.7678 -43.87 9384.23883 -1.65793 -176.815 22575 Thr 25Jan90 01:27:5.600 268.7689 -43.87 9384.00198 -1.65535 -176.813 22575 Thr 25Jan90 01:27:5.660 268.7702 -43.87 9383.72069 -1.65229 -176.811 22575 TRAKSAT Satellite Tracking Program Page 32 this example was run using the real-time mode and the default tracking station, Huntsville, Al.. In this case the LONG is the satellites longitude, positive (+) means EAST longitude while negative (-) means WEST longitude. The column "V" is the visibility flag, i.e., if the satellite is visible the flag is set to "Y" else it is blank. If the user had chosen to include the Ra & Dec the output would be like; Tracking Station: HUNTSVILLE, AL Satellite: Mir Date Time (UTC) Azim Elev Range Ra Dec Alt V HR:MN:Sec Deg Deg Km HH:MM:SS DD:MM:SS Km Thr 25Jan90 01:27:15.38 268.9799 -43.57 9337.76175 21:58:19 -01:05:53 388 Thr 25Jan90 01:27:15.44 268.9811 -43.56 9337.47902 21:58:20 -01:05:42 388 Thr 25Jan90 01:27:15.55 268.9835 -43.56 9336.95618 21:58:21 -01:05:22 388 the user will notice that the latitude and longitude have been replaced by the Ra & Dec. ****************** * IMPORTANT NOTE * ****************** The Ra & Dec are based on the J2000 epoch, 1,1.5,2000 UTC date, and are NOT user selectable, perhaps in the next version of TRAKSAT. The J2000 epoch is the "current" epoch on most star charts. The user will notice that the header is stationary just the data is scrolling. This option is useful for a quick view of tracking data, since no graphics are used. If the user was in delta-time mode the step between outputs would be the delta time step value set. ****************** * IMPORTANT NOTE * ****************** To stop the display the user can press any key and the screen will "freeze". The user will need to press any key again to continue the simulation. Pressing ESC will return the user to the main menu. If the output was directed to a file the tracking data output file name will consist of the first 8 characters of the satellite name with the extension ".PRT" added to the end. The name of the output file will be displayed for the user. An example could be the satellite Mir, the filename for output would be "Mir.PRT". ****************** * IMPORTANT NOTE * ****************** The program will produce the file xxxxxxx.PRT, the x being the current satellite name, if one is not found, but will OVERWRITE TRAKSAT Satellite Tracking Program Page 33 an old one if found. The user will have the responsibility to re- name the file after completing a run if they would like to save the output. The output in the file is very similar to the screen output option. Below is an example of the file output mode; TRAKSAT Version 1.90 Tracking Station: HUNTSVILLE, AL [ Line Of Sight (LOS) Visibility ] Satellite: Mir Satellite Data Set: 1 16609U 86 17 A 90 91.75081924 .00058269 00000-0 66933-3 0 5052 2 16609 51.6174 355.6250 0013230 341.6181 18.4560 15.61365027236165 Date Time (UTC) Azim Elev Range Lat Long Rev V HR:MN:SEC Deg Deg Km Deg Deg Thr 25Jan90 01:26:42.04 268.26 -44.61 9494.42 -2.86 -177.67 22575 Thr 25Jan90 01:26:42.21 268.26 -44.60 9493.63 -2.86 -177.66 22575 Thr 25Jan90 01:26:42.32 268.27 -44.60 9493.12 -2.85 -177.66 22575 Thr 25Jan90 01:26:42.43 268.27 -44.60 9492.60 -2.84 -177.65 22575 again this example used the real-time mode. This output is a standard 80 columns, for printers or the 25x80 text screen. In this example a line of sight (LOS) mode was chosen. If the visibility mode was optical the header, the line under the tracking station name, would display; [ Optical visibility ]. If the file mode and the real-time mode are chosen the screen will display the number of records that have been written to file. The program DOES check the remaining disk space and stops the program if the record space exceeds available disk space. The data prior to exceeding the disk space is written and an error message is displayed, no data will be lost. It is recommended that the real-time mode NOT be used for file output, mainly because of the large files that could be produced. If the file mode and delta-time mode are chosen the screen will display the same record count as above, but also the total number of records to calculate. This method produces the smallest file size the user requires. The total number of records to calculate would be; total_records = (stop_time - start_time)/delta_time. The size of the file is approximately 81 bytes per record, therefore 1440 records, one day at one minute intervals, will produce a file size of about 116K. (ALL TIME STEPS DISPLAYED). TRAKSAT Satellite Tracking Program Page 34 ****************** * IMPORTANT NOTE * ****************** To stop the display the user can press any key and the screen will "freeze". The user will need to press any key again to continue the simulation. Pressing ESC will return the user to the main menu. The option has been added to TRAKSAT version 1.5, and up, to display only the visible passes, based on the setting of the visibility options. The program will default to ALL passes. The output, in the tabular modes, can display Ra & Dec of the satellite also. The coordinate used is based on J2000 epoch, this was chosen to be used with "current" star charts. The default is to include Ra & Dec in the output. Output Batch Mode Options TRAKSAT version 2.55 and above has included a new option, called Batch Mode. This option is similar to the Tabular Output mode but can be used on all or a user defined list of satellites. The method used in this option is; enter into the delta time mode and select the starting date/time and length of the simulation. The next step is to select Batch Mode from the Output options. The program will prompt the user for some additional information and then run each satellite through the delta tabular mode one at a time. The output from this option can go to the screen or a file, the file name is called TRAKSAT.000 (or TRAKSAT.001, TRAKSAT.002... until a new extension is found). Below is an example of the file output created with this option. The starting date/time was 10- 24-90 00:00:00 UTC to 00:05:00 UTC by one minute steps. TRAKSAT Satellite Tracking Program Page 35 The output parameters are similar to the tabular output but without the rev, altitude, and earth position quantities. (Batch Mode File Output) TRAKSAT Version 2.55 Tracking Station: Huntsville, AL [ Optical Visibility ] Input File: NASA761.TXT Satellite Date Time (UTC) Azim Elev Range Ra Dec V HR:MN:Sec Deg Deg Km HH:MM:SS DD:MM:SS Alouette 1 24Oct90 00:01:00.0 27.55 7.01 3077.80 05:08:29 +52:26:57 Y Alouette 1 24Oct90 00:02:00.0 34.78 9.25 2887.38 04:26:20 +49:17:17 Y Alouette 1 24Oct90 00:03:00.0 43.00 11.16 2736.46 03:47:43 +44:27:25 Y Alouette 1 24Oct90 00:04:00.0 52.10 12.57 2632.56 03:14:32 +38:06:22 Y ATS 3 24Oct90 00:01:00.0 203.66 31.30 38434.42 18:57:57 -20:17:56 Y ATS 3 24Oct90 00:02:00.0 203.65 31.30 38434.70 18:58:59 -20:18:07 Y ATS 3 24Oct90 00:03:00.0 203.64 31.30 38434.96 19:00:01 -20:18:17 Y ATS 3 24Oct90 00:04:00.0 203.63 31.30 38435.20 19:01:03 -20:18:26 Y LAGEOS 24Oct90 00:03:00.0 60.59 .43 10507.93 03:35:30 +24:05:41 Y LAGEOS 24Oct90 00:04:00.0 59.38 1.77 10359.46 03:35:09 +25:52:41 Y GPS-0002 24Oct90 00:01:00.0 182.73 .89 25515.07 20:05:13 -54:15:49 Y GPS-0002 24Oct90 00:02:00.0 182.65 1.31 25464.60 20:06:55 -53:50:49 Y GPS-0002 24Oct90 00:03:00.0 182.58 1.73 25414.03 20:08:36 -53:25:41 Y GPS-0002 24Oct90 00:04:00.0 182.50 2.16 25363.37 20:10:16 -53:00:25 Y ****************** * IMPORTANT NOTE * ****************** To use the Batch Mode the user MUST be in the delta time mode. The program will warn the user if a real time mode is currently set. ****************** * IMPORTANT NOTE * ****************** The user can freeze the screen in the SCREEN OUTPUT MODE ONLY, the file output option will only accept the Esc (escape) key to stop the simulation. To stop the display the user can press any key and the screen will "freeze". The user will need to press any key again to continue the simulation. Pressing ESC will return the user to the main menu. This option will check the disk to determine if the output will fit on the disk. If the disk is full the program will display an error message and terminate that run. The output file produced with this option can get very large. The user should pick a time span or time step that will produce only the data required to lessen the disk storage space. TRAKSAT Satellite Tracking Program Page 36 (Editors note) The idea for this new option was inspired from searching for a satellite trail left on a CCD captured graphics image file. The date, "rough" time, and position of the "exposure" were known but no idea on what the satellite was that passed through the image. Using the Batch Mode and a satellite data set from that time period the satellite was found. The idea of going through the satellite file one satellite at a time was just too much! So out came the Batch Mode to help in this kind of search. Here is another use for the Batch Mode; one night I was tracking IRAS passing north to south over head when another satellite came into view heading almost opposite the path of IRAS. I actually saw two different satellites at the same time! I wish I had the Batch Mode at that time, it would have been easy to discover that unknown satellite. Visibility Options There are two different methods used by TRAKSAT to determine visibility. The first method is simply when the elevation is greater than zero degrees the satellite will be visible to the tracking station. This method is called line of sight (LOS) in the program. This method would be suitable for monitoring satellite radio transmissions, interesting RF signals no doubt. It should be noted that at most tracking sites zero degrees elevation is not visible due to ground based obstructions, i.e. trees buildings, and other such objects. A rule of thumb is if you hold out your arm straight and stick out your thumb horizontal to the ground so it appears to touch the horizon the upper edge of your thumb is about two degrees elevation, while your closed fist is about ten degrees elevation. The second method, optical visibility, requires the satellite to be above zero degrees elevation also, however the satellite must be sun-lit while the tracking station is in darkness. This method would be used for viewing satellites with the aid of say binoculars. Remember that three conditions must be meet for the satellite to be optically visible. 1. The elevation angle to the satellite must be above zero degrees as seen from the tracking station. 2. The sun must be BELOW -12 degrees elevation at the tracking station. (NAUTICAL TWILIGHT) (As of version 2.60 and above the user can set the type of twilight, the range of settings available is from -5° to -22°. The -12° is the recommended setting.) 3. The satellite must "see" the sun or the satellite must be in the sun light not the earth shadow. TRAKSAT Satellite Tracking Program Page 37 It is of interest to note that some satellites are NOT visible even if the elevation angle is above the horizon, because they are in the earth's shadow. It is difficult to observe a satellite "coming out" of the earth's shadow, it is easier to see the entrance into the shadow. If the lighting conditions are favorable a "bright" satellite can be seen with the naked eye also. The best time for these favorable lighting conditions usually occur an hour before sun rise or an hour after sun set, as seen at the tracking site. The best type of satellite is low, about 250 - 400 kilometer altitude, ones for naked eye observations. (Mir, Hubble, Shuttle are a good examples.) ****************** * IMPORTANT NOTE * ****************** The rcommended twilight setting is -12°, i.e., the sun is greater than or equal to -12 degrees BELOW the local horizon, to determine the lighting conditions. The user CAN change the type of twilight used in TRAKSAT, i.e., civil, nautical, or astrodynamic, when using the optical visibility options. The type of visibility is set from the main menu Visibility option, the default is to use the OPTICAL method. If the user would like to change the visibility method, select from the main menu the visibility option. The Current Status Box will always print the type of visibility test that will be performed by the program. ****************** * IMPORTANT NOTE * ****************** With either method the visual magnitude is NOT calculated. Such a calculation would require knowledge about the emissivity of the satellite, and atmospheric conditions, neither of which is readily available to the user. Output Multi-Tracking Options TRAKSAT version 1.7 and above have the capability to track several satellites at the same time. The main menu output option will ask the user for either a single or multi-track of satellites. If the user selects Multi-Track the multi-track output menu will appear asking the user to select ground track or tabular output modes. The Current Status Box will display the output option (ground track or tabular) along with the :(Multi) title. This will clue the user that the multi-track options are active. The user can also display the current multi-tracking satellites from this menu. TRAKSAT Satellite Tracking Program Page 38 ****************** * IMPORTANT NOTE * ****************** The user can ONLY change the satellite names by editing the TRAKSAT.DEF file and changing the default names. The format for the satellite names is as follows; COLUMN 1 - through - 15 CAN BE ANYTHING, COLUMN 16 STARTS THE SATELLITE NAME, THE NEXT 12 CHARACTERS USED ARE THE NAMES OF THE SATELLITES TO TRACK. Below is an example, this is the data included in the TRAKSAT.DEF file. Satellite # 1: MIR Satellite # 2: SALYUT 7 Satellite # 3: IRAS Satellite # 4: SEASAT 1 Satellite # 5: EGP Satellite # 6: NOAA 9 It is recommended that the FULL name of the satellite be used, the search routine will use the first match found and not look for any other matches. If the name of a satellite is not found the output will display a NO DATA, i.e., no data for the requested satellite has been loaded. The first blank satellite name will stop the search for any remaining satellites, however if the satellite is not found any remaining satellites will be searched for. Six satellites MAXIMUM can be tracked, if the TRAKSAT.DEF has fewer than TWO the program will issue an error and return to the main menu. (Use the single tracking mode.) If the ground track option is chosen the program will proceed to plot the tracks on the world map. The plots are very similar to the single satellite plots, except that for every satellite a different colored line is drawn. The order of the colors are; 1st satellite = yellow 2nd satellite = cyan 3rd satellite = green 4th satellite = lite red 5th satellite = lite magenta 6th satellite = lite green. (The colors can NOT be changed by the user) ****************** * IMPORTANT NOTE * ****************** Users with monochrome monitors will have trouble identifying the ground tracks in the multi-track mode as no difference in the colors will be seen. As of TRAKSAT version 1.90 and above a number (1 - 6) along with the "starting circle" is plotted to TRAKSAT Satellite Tracking Program Page 39 help identify the satellite on the monochrome screen. Below is an example of the multi-track ground tracks. It is noted that no actual graphics plot is included due to the limits of storing graphics and text together. -------------------▌ TRAKSAT Version 1.80 ▐------------------ | UTC 17:17:36.3 Date 2/20/1990 Satellite Name: MULTI-TRACKING | | Local 11:17:36.3 Date 2/20/1990 Tracking Station: HUNTSVILLE, AL| | | | (The version number may be different in this display.) | | (no world map drawn in this example) | | | | Mir Salyut 7 IRAS SeaSat 1 EGP NOAA 9| |Azi 32.079 227.66 274.10 220.47 4.9673 2.2960| |Ele 14.499 -60.75 -50.48 -57.27 33.954 -15.43| ---------------------------------------------------------------------- The output will display the ground tracks, the azimuth as seen from the tracking station, and the elevation. The elevation is the angle above or below the tracking station horizon. The output is in degrees, with the time and date formats being; HH:MM:SS.s and MM/DD/YYYY. (The version number may be different in this display.) ****************** * IMPORTANT NOTE * ****************** No visibility methods, LOS or optical, are used in the multi- track GROUND TRACK modes. THE TABULAR OUTPUT MODES WILL DETERMINE THE VISIBILITY BASED OF THE SETTING OF THE VISIBILITY OPTION, (LOS or Optical). (The user can determine the LOS visibility by looking at the elevation angles displayed when using the ground track option.) TRAKSAT Satellite Tracking Program Page 40 MULTI-TRACKING TABULAR OUTPUT MODE As of TRAKSAT version 2.30 and above a tabular multi-tracking mode has been included. The output is in text rather than a graphic display mode. Below is an example of the multi-tracking tabular output mode. The different satellites will be displayed in different colors also, the colors are the same as the ground track options. ╔═════════════════════╡ TRAKSAT Version 2.30 ╞═══════════════════════╗ ║ Tabular Multi-Tracking Mode ║ ║ Tracking Station: HUNTSVILLE, AL Input Data File: NASA707.TXT ║ ║ UTC 00:10:00.0 Date 6/19/1990 ║ ║ Local 00:10:00.0 Date 6/18/1990 ║ ╟─────────────────────────────┤ Mir ├─────────────────────────────╢ ║ Latitude -12.0376° Azimuth 283.3060° Range 11839.43 Km ║ ║ Longitude 42.4516° Elevation -63.4864° NOT Visible ║ ╟─────────────────────────────┤ Salyut 7 ├─────────────────────────────╢ ║ Latitude -5.4339° Azimuth 249.6659° Range 7706.61 Km ║ ║ Longitude 209.8406° Elevation -33.6718° NOT Visible ║ ╟─────────────────────────────┤ HST ├─────────────────────────────╢ ║ Latitude 21.5907° Azimuth 350.3650° Range 11762.57 Km ║ ║ Longitude 102.0782° Elevation -60.0983° NOT Visible ║ ╟─────────────────────────────┤ SeaSat 1 ├─────────────────────────────╢ ║ Latitude 59.6848° Azimuth 328.8212° Range 7653.05 Km ║ ║ Longitude 20.8611° Elevation -29.3966° NOT Visible ║ ╟─────────────────────────────┤ EGP ├─────────────────────────────╢ ║ Latitude -2.4094° Azimuth 106.5518° Range 8414.05 Km ║ ║ Longitude 338.9396° Elevation -27.4664° NOT Visible ║ ╟─────────────────────────────┤ IRAS ├─────────────────────────────╢ ║ Latitude 57.6857° Azimuth 354.3749° Range 9450.31 Km ║ ║ Longitude 82.8507° Elevation -39.6712° NOT Visible ║ ║ ║ ╚═══════════════════════════════════════════════════════════════════════════╝ The output of the multi-tracking mode is similar to the bottom two lines of a ground track plot. The output will display only satellites found in the element file. TRAKSAT Satellite Tracking Program Page 41 Main Menu Quit Option This option will stop the TRAKSAT program and return the user to DOS. If the tracking station data was changed during the program execution, the user will be asked if the new data should replace the old default data. That choice is up to the user to decide. The old data will be displayed along with the current data to help the user with the choice. THE DEFAULT IS NOT TO SAVE THE NEW DATA. USER DEFINED SATELLITE PLOTTING COLOR TRAKSAT version 2.60 and above allows the user to choose what color to plot the satellite in. The color can be changed in the file TRAKSAT.DEF or from the Main Menu System options. Below is an example of a TRAKSAT.DEF file with the default satellite plotting color as light yellow (14). To change the color edit the file TRAKSAT.DEF and change the Color = XX to any of the colors allowed. (If an incorrect color is chosen the light yellow will be used as a default.) COLUMN NUMBER 123456789012345678901234567890123456789012345678901234567890123456 2447836.50000000 Color = 14 Printer Pins = 9 HUNTSVILLE, AL 34.7317000 273.4033000 228.60 -5 NASA678.TXT Multi-Track Satellite Names Satellite # 1: MIR Satellite # 2: SALYUT 7 Satellite # 3: IRAS Satellite # 4: SEASAT 1 Satellite # 5: EGP Satellite # 6: NOAA 9 User Defined Satellite Names IRAS SALYUT 7 COSMOS 1686 COSMOS 1766 The user can choose from the pallette of; 2 = GREEN 9 = LIGHT BLUE 3 = CYAN 10 = LIGHT GREEN 4 = RED 11 = LIGHT CYAN 5 = MAGENTA 12 = LIGHT RED (sun term.) 6 = BROWN 13 = LIGHT MAGENTA 7 = WHITE (map land mass color) 14 = LIGHT YELLOW 8 = GRAY 15 = BRIGHT WHITE TRAKSAT Satellite Tracking Program Page 42 NORAD/NASA 2-LINE SATELLITE DATA NORAD maintains general perturbation element sets on all resident space objects. These element sets are periodically refined so as to maintain a reasonable prediction capability on all space objects. In turn, these element sets are provided to users. The input file of current orbital elements can be obtained form several BBS around the country. One such BBS is the Celestial BBS at (513) 427-0674 in Fairborn, Ohio, the SYSOP is T.S. Kelso. See section; Obtaining Satellite Data, for more information on obtaining satellite data. I have included a file of the latest elements for over 130 orbiting satellites. See section; Files Required To Run TRAKSAT. ****************** * IMPORTANT NOTE * ****************** The following two pages were downloaded from Celestial BBS, T.S. Kelso SYSOP. Effective January 1986, this system began posting the most recent element sets received from NASA/Goddard Space Flight Center for several categories of satellites: Amateur Radio, Earth Resources, Manned Spacecraft, Navigation, Weather, and NASA's 30 Day Specials (which contain objects launched within the last 30 days and are often easy to spot visually). More specifically, these include the following satellites or satellite series: OSCAR, Radio Sputnik, UOSAT, Cosmos, LandSat, SeaSat 1, SPOT, Mir, Salyut 7, Soyuz, LDEF, US Space Shuttle, NAVSTAR (GPS), GOES, Meteor, and NOAA. These elements will be maintained in ASCII format in the file. Data for each satellite will consist of three lines in the following format: AAAAAAAAAAA 1 NNNNNU NNNNNAAA NNNNN.NNNNNNNN +.NNNNNNNN +NNNNN-N +NNNNN-N N NNNNN 2 NNNNN NNN.NNNN NNN.NNNN NNNNNNN NNN.NNNN NNN.NNNN NN.NNNNNNNNNNNNNN Line 1 is a eleven-character name. Lines 2 and 3 are the standard Two-Line Orbital Element Set Format identical to that used by NASA and NORAD. The format description is: Line 2 Column Description 01-01 Line Number of Element Data 03-07 Satellite Number 10-11 International Designator (Last two digits of launch year) 12-14 International Designator (Launch number of the year) 15-17 International Designator (Piece of launch) 19-20 Epoch Year (Last two digits of year) 21-32 Epoch (Julian Day and fractional portion of the day) 34-43 First Time Derivative of the Mean Motion (rev/day^2) TRAKSAT Satellite Tracking Program Page 43 or Ballistic Coefficient (Depending of ephemeris type) 45-52 Second Time Derivative of Mean Motion (Blank if N/A) 54-61 BSTAR drag term if GP4 general perturbation theory was used. Otherwise, radiation pressure coefficient. 63-63 Ephemeris type 65-68 Element number 69-69 Check Sum (Modulo 10) (Letters, blanks, periods = 0; minus sign = 1; plus sign = 2) Line 3 Column Description 01-01 Line Number of Element Data 03-07 Satellite Number 09-16 Inclination [Degrees] 18-25 Right Ascension of the Ascending Node [Degrees] 27-33 Eccentricity (decimal point assumed) 35-42 Argument of Perigee [Degrees] 44-51 Mean Anomaly [Degrees] 53-63 Mean Motion [Revs per day] 64-68 Revolution number at epoch [Revs] 69-69 Check Sum (Modulo 10) All other columns are blank or fixed. Example: NOAA 6 1 11416U 86 50.28438588 0.00000140 67960-4 0 5293 2 11416 98.5105 69.3305 0012788 63.2828 296.9658 14.24899292346978 For a description of the mean orbital elements see section; What Are The Mean Classical Elements. Note that the International Designator fields are usually blank, as issued in the NASA Prediction Bulletins. All epochs are UTC. Satellites will be ordered by their NASA Catalog Number. The data file will be updated as soon as possible after receipt of new element sets or whenever element sets are received for the Space Shuttle. TRAKSAT Satellite Tracking Program Page 44 The following pages contain a brief overview of the methods used in TRAKSAT and are included to help the reader understand the mechanics of an orbiting satellite about the earth. WHAT ARE THE MEAN CLASSICAL ELEMENTS Five independent quantities called "orbital elements" are sufficient to completely describe the size, shape and orientation of an orbit. A sixth element is required to pinpoint the position of the satellite along the orbit at a particular time. The classical set of six orbital elements are defined as: 1. a, semi-major axis, a constant defining the size of the conic orbit. 2. e, eccentricity, a constant defining the shape of the conic orbit. 3. i, inclination, the angle between the Z axis, i.e. like the North Pole, and the angular momentum vector, h = R X V, i.e. the vector R crossed with the vector V. 4. Ω, longitude of the ascending node, the angle, in the fundamental plane, between the Greenwich Prime Meridian and the point where the satellite crosses the fundamental plane in a northerly direction, (ascending node). This angle is measured counterclockwise when viewed from the north side of the fundamental plane. 5. w, argument of periapsis, the angle, in the plane of the satellite's orbit, between the ascending node and the periapsis point, measured in the direction of the satellite's motion. 6. T, time of periapsis passage, the time when the satellite was at periapsis. 6a. Sometimes the time of periapsis passage is replaced by the true anomaly, v, the angle, in the plane of the satellite's orbit, between perigee and the position of the satellite at the particular time, t0, called the epoch. * (To convert from T to v) v = (360 deg) * t0 / T 6b. The NASA/NORAD element sets include the right ascension of the ascending node (RAAN) instead of the longitude of the ascending node but the conversion is between the two is not hard to do. TRAKSAT Satellite Tracking Program Page 45 I have included an example of the conversion of RAAN to longitude of ascending node. This example can be done with TRAKSAT and a simple routine to find the sidereal time (GST). It is left up to the user to determine the conversion from longitude of ascending node to RAAN. Elements used for study (From NASA755 element set) Mir 1 16609U 90272.82451929 .00046194 00000-0 56285-3 0 9636 2 16609 51.6113 162.6955 0026137 101.1206 259.2727 15.59612888264453 From the example 2-line elements for Mir the epoch is; 9-29-1990 @ 19.78846296 UTC (19h 47m 18.4666s). The GST for that date and time is 305.1334 deg.. From the elements the RAAN is 162.6955 deg.. Therefore: Longitude = RAAN - GST -142.4379 = (162.6955 - 305.1334) TRAKSAT will only allow the integer second for the starting time but 19h 47m 19s is close enough! Below is the output captured from the screen output with Mir elements. As you can see the longitude is the same as the calculated value above. (Allowing for the small time difference .5333 seconds.) Output from TRAKSAT TRAKSAT Version 2.50 Tracking Station: Huntsville, AL Satellite: Mir Date Time (UTC) Azim Elev Range Lat Long Rev V HR:MN:Sec Deg Deg Km Deg Deg -- Rev # 26445 -- Sat 29 Sep 90 19:47:19.0 248.87 -28.40 6818.87 .0275 -142.4186 26445 The sharp reader will notice that the NORAD elements do NOT include the semi-major axis, a. It is possible to calculate the semi-major axis with the data in a NORAD elements set. The approach would be; 1. Convert the mean motion into degrees per second. and calculate the time to complete one orbit, this will be called the period. 2. Using the period and the earth's gravitational constant, mu, the semi-major axis can be calculated. (equations used) xn_s = (mean motion * 360)/86400 per = 360/xn_s a = ((per^2 * mu)/(4*π^2))^(1/3) mu = 3.986012d+14 m^3/sec^2. TRAKSAT Satellite Tracking Program Page 46 The starting point for the study of motion of one body orbiting another, such as an artificial satellite about the earth, is always the two-body problem; i.e., two point masses attracted to each other according to Newton's Law of Universal Gravitation, the inverse square law. The solution is well-known; the two bodies move about each other in conic sections. For bounded motions, such as those of an earth satellite, this conic is either a circle or an ellipse. The problem can be formulated in different ways, but is always convenient to chose a coordinate system with the origin centered at one of the bodies. The position of the second body then can be specified, for example, by giving its initial cartesian position and velocity coordinates and then integrating the equations of motion to find the future positions and velocities. The cartesian system is not the most convenient one in which to represent the motion because an analytic solution cannot be obtained and the integrations must be done numerically. By adopting a polar coordinate system, one is able to effect an analytic solution referred to above which can be specified in terms of six constants of motion; five orbital elements, a,e,i,w,Ω and the time of pericenter passage T. The last constant can be, and usually is, replaced by the mean anomaly M which is a linear function of time. This is a very convenient way to specify the initial position and velocity of a satellite and it also allows an easy visualization of the motion. The position and velocity of the satellite at any future time can be specified in terms of these six constants, a,e,i,w,Ω,M and time. In realistic applications, such as artificial satellites about the earth, there are forces acting on the satellite in addition to the inverse square force although this is the dominate one. Other gravitational forces are due to distant bodies such as the moon and sun but the principal additional gravitational forces are due to the non-sphericity of the earth. All of the gravitational forces are conservative and can be represented by a potential function. In addition to these extra gravitational forces, there are non-conservative forces such as atmospheric drag. All of these forces other than the inverse square force are called perturbations. The prediction of motion considering these additional forces is called Perturbation Theory. The orbital elements, constant for pure two-body motion, become slowly varying functions of time when the perturbations are considered. Differential equations describing the time rates of change of the elements are called the Lagrange Planetary Equations, LPE and can be found in any standard book on celestial mechanics. Considering conservative forces only, which can be represented by a potential function, the part of the potential other than the two-body part is conventionally called the disturbing function, represented by R, and the LPE are: . a = 2 / n a * ( δR / δM ) . e = (-(1-e²)^½ / na²e)*δR/δw+(1-e²/na²e)*δR/δM . i = cot i/(na²(1-e²)^½ * δR/δw - δR/(δΩna²(1-e²)½) TRAKSAT Satellite Tracking Program Page 47 . w = (1-e²)^½ * δR / na²eδe - cot i * δR/(na²(1-e²)^½)*δi) . Ω = δR/(na² sin i *(1-e²)^½) * δi) M = n - 2δR/naδa - 1-e² * δR/(na²e * δe). * where δ is the partial derivative starting from the very simple representation of the gravitational potential between two point masses of magnitude m0 and mi separated by distance r as; V = -G * (m0 * mi)/r one can, by applying this to a satellite of mass m0 and to every infinitesimal mass point mi of the earth and integrating over the whole earth, arrive at the following potential function for the earth; ∞ n ∞ n m V=-µ/r(1-Σ JnPn (sinδ)(re/r)^ +Σ Σ Jnm (re/r)^ Pn^ (sinδ)cos(m(α-α))). n=2 n=2m=1 mn The first term is the one giving pure two-body motion and the additional terms are the perturbing terms. The first sum, zonal harmonics, represents the flattening and other distortions relative to the equator and the second sum, tesseral harmonics, represents the non-uniformity of the earth in longitude. If, as is frequently done, one assumes that the earth possesses rotational symmetry, then the second sum vanishes. The neglect of the second sum usually produces no noticeable effects except in the case of geosynchronous satellites. Then one must consider those terms which cause slow long-period drifts of the geosynchronous position. For close earth satellites one can usually take about three terms from the first sum and get very accurate results; even the first term alone will produce very satisfactory results in most cases for short-time periods. The Jn are constants which depend on the mass distribution in the earth and are deduced from analysis of observed satellite motions. The currently accepted values of J2, J3, and J4, which are used in TRAKSAT, are; -3 J2 = 1.082616 X 10 -6 J3 = -2.53881 X 10 -6 J4 = -1.65597 X 10 . The Pn (sin δ) are Legendre polynomials of index n and are even functions of sin δ for n even and odd functions for n odd. The J2 term describes the flattening of the earth and the J3 term the so-called pear shape. J2, which is three orders of magnitude TRAKSAT Satellite Tracking Program Page 48 larger than J3, gives rise to secular changes in the elements w, Ω, and M while J3 gives rise to long_period oscillations in e and w. In general, even harmonics cause long-period and secular changes in the elements, and odd harmonics cause long-period oscillations. Short-period oscillations can result from all terms; but since J2 is so much larger than the other coefficients, generally only the J2 short-period terms are considered. Secular terms are those which monotonically increase or decrease with time. For first order solutions this change with time is linear. Long-period terms are those which oscillate with a period of typically one to two months, and short-period terms are those which oscillate with a period of one orbital period or some rational fraction of it. To finish formulating the problem, the disturbing function is expressed in terms of the orbital elements and then the appropriate partial derivatives are taken and substituted into the LPE. One then has a coupled set of first order non-linear ordinary differential equations. Because they are non-linear, they can be solved only by various approximation methods. The usual method is to assume that the solutions can be represented in some type of power series expansion in a small parameter and arrive at sets of approximation equations which can be a close representation of the real motion, at least over short-time periods. The complete solution consists of the sum of the secular terms, short-period terms, and the long-period terms; i.e., a = a + a + a . osc s sp lp ****************** * IMPORTANT NOTE * ****************** I have NOT included the actual equations used in the program in this document for obvious reasons, i.e. they are long and hard to type in with a text based word processor. If you have an interest in these equations they are in several references I have listed. TRAKSAT Satellite Tracking Program Page 49 MODELS FOR PROPAGATION OF NORAD ELEMENT SETS NORAD maintains general perturbation element sets on all resident space objects. These element sets are periodically refined so as to maintain a reasonable prediction capability on all space objects. In turn, these element sets are provided to users. The most important point to be noted is that not just any prediction model will suffice. The NORAD element sets are "mean" values obtained by removing periodic variations in a particular way. In order to obtain good predictions, these periodic variations must be reconstructed (by the prediction model) in exactly the same way they were removed by NORAD. Hence, putting NORAD element sets into a different model (even though the model may be more accurate or even a numerical integrator) will result in degraded predictions. All space objects are classified by NORAD as near-Earth (period less than 225 minutes) or deep-space (period greater than or equal 225 minutes). Depending on the period, the NORAD element sets are automatically generated with the near-Earth or deep- space model. The PROGRAM will calculate the satellite period and know which PREDICTION MODEL TO USE. THE PROPAGATION MODELS Two mathematical models for prediction are used by TRAKSAT. The first of these, SGP4, was developed by Ken Cranford in 1970 (see Lane and Hoots 1979) and is used for near-Earth satellites. This model was obtained by simplification of the more extensive analytical theory of Lane and Cranford (1969) which uses the solution of Brouwer (1959) for its gravitational model and a power density function for its atmospheric model (see Lane, et al 1962). The next model, SDP4, is an extension of SGP4 to be used for deep-space satellites. The deep-space equations were developed by Hujsak (1979) and model the gravitational effects of the moon and sun as well as certain sectoral and tesseral Earth harmonics which are of particular importance for half-day and one-day period orbits. TRAKSAT Satellite Tracking Program Page 50 COMPATIBILITY WITH NORAD ELEMENT SETS The NORAD element sets are currently generated with either SGP4 or SDP4 depending on whether the satellite is near-Earth or deep- space. For SGP4 and SDP4 users, the mean motion is first recovered from its altered form and the drag effect is obtained from the SGP4 drag term (B*) with the pseudo-drag term being ignored. The value of the mean motion can be used to determine whether the satellite is near-Earth or deep-space (and hence whether SGP4 or SDP4 was used to generate the element set). From this information the program will decide whether to use SGP4 or SDP4 for propagation and hence be assured of agreement with NORAD predictions. TRAKSAT Satellite Tracking Program Page 51 PROGRAM LIMITATIONS AND ASSUMPTIONS The ephemeris equations DO include the zonal harmonics, through 2nd order, of the gravitational potential. This implies a gravitational field produced by an oblate spheroidal earth unsymmetrical with respect to the equator, pear-shaped. In other words, the ephemeris equations contain J2, J3, and J4 terms. The currently accepted values of J2, J3, and J4, which are used in TRAKSAT, are; -3 J2 = 1.082616 X 10 -6 J3 = -2.53881 X 10 -6 J4 = -1.65597 X 10 . The earth equatorial radius used by TRAKSAT is; 6378.135 Km, while the flattening factor used is 1/298.257 (both are from the 1972 WGS models). The program TRAKSAT models only ELLIPTICAL orbital motion about the earth. That is, the orbital eccentricity MUST BE LESS THAN ONE and GREATER THAN ZERO. Very small eccentricities are acceptable, i.e., such as 0.0000001. TRAKSAT will propagate NORAD/NASA 2-line elements until the altitude above the earth reaches 150 Km. This is due to the fact that at 150 Km altitude the satellite will decay from orbit very soon. The prediction process is not as accurate for such a low satellite. (The remaining lifetime of a low satellite would be on the order of a day or two.) STARS USED IN TRAKSAT The star background option will use the following list of stars for the display. The star data values are from USNO Floppy Almanac 1988, Version 2.11.88, file STAR1.CAT using Epoch J2000 coordinates. Bayer Name Proper Name ---------- ----------- Ursae Minoris Polaris Andromedae Alpheratz Phoenicis Ankaa Cassiopeiae Schedar Ceti Diphda/Deneb Kaito Eridani Achernar Arietis Hamal Eridani Acamar TRAKSAT Satellite Tracking Program Page 52 Ceti Menkar Persei Mirfak Tauri Aldebaran Orionis Rigel Aurigae Capella Orionis Bellatrix Tauri Elnath Orionis Alnilam Orionis Betelgeuse Carinae Canopus Canis Majoris Sirius Canis Majoris Adhara Canis Minoris Procyon Geminorum Pollux Carinae Avior Lambda Velae Suhail Carinae Miaplacidus Hydrae Alphard Leonis Regulus Ursae Majoris Dubhe Leonis Denebola Corvi Gienah Crucis ACrux Crucis GaCrux Ursae Majoris Alioth Virginis Spica Ursae Majoris Alkaid Centauri Hadar Centauri Menkent Boötes Arcturus Centauri A Rigil Kentaurus Librae Zubenelgenubi Ursae Minoris Kochab Coronae Borealis Alphecca Scorpii A Antares Triangulii Atria Ophiuchi Sabik Lambda Scorpii Shaula Ophiuchi Rasalhague Draconis Eltanin Sagittarii Kaus Australis Lyrae Vega Sagittarii Nunki Aqilae Altair Pavonis Peacock Cygni Deneb Pegasi Enif Gruis Al Na ir Piscis Austrini Fomalhaut Pegasi Markab USER DEFINED STAR DATA The option of using your own star data in TRAKSAT is included. Up to 1500 stars can be included in a data file. ** ALL STAR DATA WILL NEED TO BE FOR EPOCH J2000. ** TRAKSAT Satellite Tracking Program Page 53 The following description of the data base format is included for the user. All star data files are in standard ASCII code. See section; Files Required To Run TRAKSAT for a sample star data file. User defined star data has the following format: GGGCCC HHMMD+DDMM +M.M +C.CC ---------------------------- GAMCAS 00567+6043 +2.4 -0.15 GA2AND 02039+4220 +2.3 +1.37 39 ARI 02479+2915 +4.5 +1.11 HR961 03203+7744 +5.5 +0.19 where GGG is the first three characters of the Greek name of the star OR the first two characters and a superscript number OR the Flamsteed number of the star. Alpha is ALP, beta is BET, gamma is GAM, and so on. Omicron and Omega are abbreviated OI and OE to distinguish them. CCC is the standard three-letter abbreviation of the constellation name -- ORI for Orion, UMA for Ursa Major, CVN for Canes Venatici. If the star has neither Greek letter nor Flamsteed number, then GGGCCC becomes is "HR" plus the four-digit Yale Bright Star Catalog number. HHMMD+DDMM is the star's location in right ascension and declination coordinates for Epoch J2000. HH is hours, MM is minutes, and D is decimal minutes of RA. +DD is declination degrees and MM is declination minutes. The coordinates, as given, are precise enough for virtually any computer graphics application. +M.M is the star's visual magnitude in yellow light, essentially how bright the star appears to the eye. The sign is necessary because some of the brightest stars, like Sirius, have negative magnitudes. Finally +C.CC is the B-V "color index" of the star. This number ranges from -0.25 to +2.5. The "bluest" stars have the lower or negative B-V color, while red stars have color indices over 1.6 or so. The Sun has a B-V of +0.62, and is a yellow-white star. TRAKSAT does not use the color data for any calculations. We thus decode the examples as: Gamma Cassiopeiae, a medium-bright blue star at 0 hours 56.7 minutes right ascension and +60 (degrees) 43' declination; Gamma-2 Andromedae as a reddish star of approximately the same brightness; 39 Arietis doesn't have a Greek letter name; and HR 961 is the 961st entry in the Yale Bright Star Catalog, barely visible to the naked eye. The user defined star data option will NOT display the star names. (There would not be any room on the screen to see the orbital track!) The format used is popular with several star map programs and should be available to the user. (A star file is now included with TRAKSAT.) TRAKSAT Satellite Tracking Program Page 54 ACCURACY OF TRAKSAT Several people have asked the question; " How accurate is TRAKSAT ?". To answer such a question one must define a set of limits. The real "acid test" is to have a prediction from TRAKSAT and then go outside and observe that satellite, taking note of the time and position of the satellite. A comparison between actual observed data and predicted can then be determined. Another approach is to compare the output from TRAKSAT against several other satellite tracking programs. Both the public domain and the commercial markets have several good tracking programs that the user could compare with. The later approach, that is the comparison between tracking programs, has been carried out by several people including myself. The output from TRAKSAT compares very well with many of the "current" tracking programs (both commercial and public domain). It could be concluded from a simple test of TRAKSAT that it agrees with several other tracking programs. (Gee we all can't be wrong!) The next step is one of comparing predicted output and observed data. The most popular use for TRAKSAT has been in the optical sighting options. The optical sighting of a satellite will be the "acid test" used for this accuracy test. First a note about NASA 2-line elements, low earth satellites (about 15 rev per day satellites) have larger disturbances from the atmosphere than higher satellites. The drag on a satellite can cause purtubations greater than the J2 terms therefore the drag term is of great importance. The very latest elements for the low earth satellite can greatly improve the prediction process, while the higher satellites do not require as current of elements. (The term low will be in the range of 250 - 375 kilometers altitude.) Reports about TRAKSAT (and its predictions) have been made on the MIR satellite along with several other low earth satellites. The bottom line being LESS THAN 30 SECONDS ERROR (prediction vs. actual) for 10 day old satellite element sets. If the satellite elements are 20 days old the error is about 60 seconds. If the elements a only a day or two old, errors of less than 10 seconds are possible (several reports have been made about 2-10 seconds of error). The position data is on the money, it is the time at that position that usually drives the accuracy of the observation. The higher earth satellites generally have less than 30 seconds of error for 20 day old elements. A NOTE MUST BE MADE ABOUT THE ERROR ANALYSIS, THE ASSUMPTION IS MADE THAT NO ORBITAL MANEUVERING WAS DONE TO THE SATELLITE DURING THE "TEST" PERIOD. (The STS-31, the Hubble launch, was a prime example of several orbital maneuvers changing the predicted observed times). In general it can be said that the most current elements are the TRAKSAT Satellite Tracking Program Page 55 best ones for planning the evenings viewing. (Elements over 30 days old can have a very large error to them). Element sets 7 -14 days old will be acceptable for most users. NORAD/NASA updates the satellite elements for this very reason, to keep the prediction process accurate. The Hubble Telescope is a good example of a "high" satellite that is fairly easy to see because it is bright. Myself and others have reported actual vs. predicted times of shadow entry to within 10 SECONDS with 13 day old elements! That is less than one second per day error! This example of HST is worth noting about the accuracy of TRAKSAT and the age of element sets. If the satellite of interest is lower than HST the newer the elements should be to maintain the accuracy. TRAKSAT Satellite Tracking Program Page 56 A BRIEF EDITORIAL One of the first decisions to be made when setting out to write a program is the choice of a programming language. I'm an Aerospace Engineer working for a company in Huntsville, Al. My job title is; Trajectory Analysis Engineer. I work with NASA, mostly the shuttle program, and design trajectories for several upcoming shuttle missions. I have written large trajectory simulations programs, for the most part they were written in FORTRAN. I know FORTRAN is not the best language to use for programs that use graphics, but Microsoft has come up with the ideal solution. Microsoft FORTRAN, version 4.0 and higher, can call BASIC, C, and PASCAL routines. Microsoft FORTRAN version 5.0 also contains graphic routines that were used in TRAKSAT, these graphic routines are the same as used in QuickC version 2.5. Most (75%) of the TRAKSAT program is written in FORTRAN to get the best speed and high precision mathematics and C, Microsoft C version 6.0, for some useful utilities and the menus. I have found this combination to be very powerful and useful for program development. TRAKSAT Satellite Tracking Program Page 57 SPECIAL THANKS I would like to take this opportunity to thank the many people who helped me either directly or indirectly on this program. First of all my wife, Anita, who understands why I have a hobbie like computers and enjoy working with them. She has not complained about the many hours, in excess of 700 hours, I have spent working on TRAKSAT. TRAKSAT version 2.60 has some 21,700 lines of code and IS STILL GROWING! Dave Ransom Jr., of Rancho Palos Verdes, CA. has kept me going when my interest in the program was slipping away. I did use the city data from his excellent program ASTROCLOCK. I also used several of the references Dave listed in his program. I would highly recommend his program to any person interested in astrodynamics. The documentation supplied with ASTROCLOCK is in itself very interesting reading and very well done. I could only hope that someday TRAKSAT will have that level of professionalism. My thanks to Dave and his wife Vicki. John Williams and Dr. Jeff Wallach, from the Dallas DataLink BBS, have been very helpful in this project also. They have offered data and a helping hand with TRAKSAT. The DataLink BBS has a vast amount of satellite information along with other interests. I would recommend it to others interested in satellite tracking. The DataLink BBS is THE place to learn about obtaining satellite images. My thanks to John and his family. I would also like to thank T.S. Kelso, SYSOP of the Celestial BBS where current satellite data can be downloaded. Several satellite tracking programs are also available on his BBS along with a vast amount of satellite information. To the many other people who have helped with a steady stream of ideas and improvements, thanks! TRAKSAT Satellite Tracking Program Page 58 QUESTIONS AND COMMENTS I would very much like to hear from anyone interested in this program and astrodynamics in general. I have not included the source code to TRAKSAT because most people do not have a Microsoft FORTRAN compiler nor a working knowledge of FORTRAN. The high cost ($500.00) of both the FORTRAN and C compilers makes the cost of working on a project like TRAKSAT expensive also. I have retained any and all commercial rights to TRAKSAT and as such can only control its use by controlling the source code. As for the choice of FORTRAN compiliers there are many fine products out and I have used many of them. However, the only compilier that supports mixed language is Microsoft. For this reason alone I would recommend it to others interested in programming. At this time I feel that TRAKSAT is still going through some "growing pains" and I would like the chance to improve it and add new features. The only way this can happen is if you, the user, takes the time to leave me messages or mail on problems or suggestions. I will try to answer your messages in a timely manner. One of the major goals of this project is to make the finest, easiest to use, satellite tracking program available. A program the average person can use and successfully track satellites. I would suggest the user to OBTAIN A COPROCESSOR if they do not have one already. A coprocessor speeds up math intensive programs, such as TRAKSAT, to a level that was only dreamed about a few years ago. Please feel free to contact me to discuss TRAKSAT or other computer problems. I can reached through the RPV BBS; RPV BBS Rancho Palos Verdes, Ca. 213-541-7299 24 hours, 2400/1200 baud. This BBS is owned and operated by Dave Ransom Jr.. I call up the BBS three or four times a week to check my mail and do some file transfers. This BBS is geared towards Astronomical interests. The latest version of ASTROCLOCK can be downloaded from this BBS also. Other BBS's I frequent are; Celestial RCP/M DataLink RBBS System Fairborn, Ohio Dallas, Texas 513-427-0674 214-394-7438 24 hours, 2400/1200 baud, 24 hours, 9600/2400/1200 baud. TRAKSAT Satellite Tracking Program Page 59 I can also be reached at work or home, please no calls after 10 PM Central Time. Please leave a phone number and the best time to call on any messages that require by personal attention. My work number has an answering machine pick-up if I can not be reached. The last, and slowest method to reach me is with the U.S. mail service, I will respond with a phone call if at all possible. Paul E. Traufler 111 Emerald Drive Harvest, Al. 35749 Phone (work) 205-726-5511 Phone (home) 205-830-8450 TRAKSAT Satellite Tracking Program Page 60 FUTURE UPGRADES TRAKSAT is free for NON-COMMERCIAL use only. The user can obtain the latest version of TRAKSAT from several BBSs around the country. The BBSs listed under section; Questions and Comments list several places to obtain the current version. Compuserve has TRAKSAT and many other related files also. ***** The non-registered user of TRAKSAT. ***** For a small fee I will mail TRAKSAT on a disk, 360K, 1.2M, 1.44M if that is the easiest way to obtain the latest version, (1.2M is best for me). Send a self addressed and stamped disk to the author along with $10.00 to the address above. STATE DISK SIZE IN YOUR LETTER !!!! ***** FLASH ********** FLASH ********** FLASH ********** FLASH ***** SAVE YOUR PRINTER! Thats right save your printer from printing out the TRAKSAT document file (60+ pages). Send $15.00 to the author and receive a laser printed copy in "booklet" form. ***** FLASH ********** FLASH ********** FLASH ********** FLASH ***** TRAKSAT AND ITS COMPANION FILES ARE BEING DISTRIBUTED AS SHAREWARE. YOU ARE ENCOURAGED TO SHARE THIS SOFTWARE WITH OTHERS PROVIDED THAT IT IS DISTRIBUTED COMPLETE WITH DOCUMENTATION AND IN UNMODIFIED FORM AND THAT NO FEE OR OTHER CONSIDERATION IS CHARGED OR ACCEPTED. ***************************************************************** ***************************************************************** TRAKSAT is free for NON-COMMERCIAL use only. THERE IS NO FIXED CHARGE FOR THIS PROGRAM, but in the spirit of the shareware concept, if the end user finds this package useful, and would like to help fund development of enhancements to this package, any amount that the end user feels is appropriate for the value received in using this package will be gladly accepted (perhaps $25.00). Please mail any donations to the above address. ANYONE WHO SENDS A DONATION WILL RECEIVE A REGISTERED COPY OF TRAKSAT AND BE PLACED ON THE UPDATE LIST FOR FUTURE UPDATES TO THE PROGRAM. This copy will give the user credit for supporting the shareware concept. PLEASE STATE THE DISK SIZE YOU REQUIRE!!!! TRAKSAT Satellite Tracking Program Page 61 ***** The registered user of TRAKSAT. ***** TO OBTAIN ANY FUTURE VERSIONS OF TRAKSAT WILL REQUIRE THE USER TO SEND A SELF ADDRESSED AND STAMPED DISK TO THE AUTHOR. (NON- REGISTERED USERS WILL BE REQUIRED TO SEND $10.00 ALONG WITH THE DISK ALSO.) PLEASE STATE THE DISK SIZE YOU REQUIRE!!!! ***************************************************************** ***************************************************************** THE REGISTERED VERSIONS OF TRAKSAT ARE FOR PERSONAL USE AND ARE NOT TO BE USED COMMERCIALLY. If you find TRAKSAT useful and would like to use it in a commercial operation please call or write for more information. OBTAINING NORAD SATELLITE DATA SETS The following BBS's have the current satellite data files; Celestial RCP/M Fairborn, Ohio SYSOP: T.S. Kelso 513-427-0674 24 hours, 2400/1200 baud, 8 bit NO parity 1 stop. Datalink RBBS System Dallas, Texas SYSOP: Dr. Jeff Wallach 214-394-7438 24 hours, 9600/2400/1200 baud, 8 bit NO parity 1 stop. RPV BBS Rancho Palos Verdes, Ca. SYSOP: Dave Ransom Jr. 213-541-7299 24 hours, 2400/1200 baud, 8 bit NO parity 1 stop. To obtain the elements from the Celestial RCP/M BBS, (with the least amount of trouble), just dial up the BBS and login. The next step is to type "F" (without the quotes) to go to the Files section, then to area #1. The next step is to type "D", for download and then type "BULLETIN.ARC" as the file to download, open an XMODEM file transfer mode with your telecommunications software. This will transfer the NASA 2-line elements to a file on the users computer. Log out of the BBS and then unarchive the file using several of the unarchiving programs, (PAK, ARC, PKZIP, etc.). TRAKSAT Satellite Tracking Program Page 62 The downloaded file will have some characters at the top of the file that will need to be removed with a word processor (this MUST save the file in pure ASCII, i.e., PC-Write, Edlin etc. works very well). (This method assumes that an account is available to the user). NASA can provide up to 20 satellite data sets (HARD COPY FORM ONLY) if the user writes and requests them. This service is free but the user will need to enter the elements into a file for use with TRAKSAT. (This is done the old fashion way, you TYPE them!) NASA Goddard Space Flight Center Control Center Support Section Code 513 Greenbelt, Md. 20771 TRAKSAT Satellite Tracking Program Page 63 FILES REQUIRED TO RUN TRAKSAT The following files should have been included in the archive file; TRAKSAT.EXE The program. TRAKSAT.DEF The default data for the tracking station. TRAKSAT.CTY The city file for tracking stations. TRAKSAT.DOC TRAKSAT program documentation. EARTH.DAT World map data file. NASAxxx.TXT This is the latest NORAD satellite data set, (element set #xxx, the xxx will be a number). READ.ME Latest notes about the program. MSHERC.COM This utility is used for Hercules graphics. MODERN.FON This is a font file used for the graphics. STARS.DAT This is a star data base that is NOT required to run TRAKSAT, it is optional. This data file can be used in the user defined star data option. STARS.DAT is almost identical to the star database used with Richard Berry's (Editor of ASTRONOMY) program STARS.BAS. For compatibility, I have retained the same database format. According to Mr. Berry's documentation file STARS.DOC, his database is essentially the same database used for the StarDome map printed in the center spread of ASTRONOMY every month. TRAKSAT Satellite Tracking Program Page 64 PROBLEMS TRAKSAT has been fully tested on many different types of computers, however due to the very nature of personal computers and different user configurations it is not possible to test the program with all possible configurations. It may be possible that some versions of DOS or some computers will not be 100% compatable and cause the program to stop. The first step to solve the problem is to read the documentation included with TRAKSAT. Users with a 8087 co-processor who experience a run-time error MAY be able to use the command "SET NO87=OK", typed without the quotes, before running TRAKSAT. What this command does is tell the program NOT to use the co-processor even if one is installed. The program will run slower but it may do the job required. After running TRAKSAT type "SET NO87=" to return to normal operation. This may work due to some bug, in some versions of DOS, that handles the co-processor. (Version 3.30 and above have corrected this bug, contact your DOS manufacture for more details.) If the user has a computer that is not 100% compatible or the graphic card is not 100% VGA compatible the program can be forced to use the EGA mode. To use this method invoke the program with "TRAKSAT/EGA", without the quotes. This will set the display to EGA modes only and MAY eliminate any graphic problems encountered. NO OTHER GRAPHIC MODES CAN BE SET THIS WAY. If you have a problem with TRAKSAT and can not resolve it please contact the author at; Paul E. Traufler 111 Emerald Drive Harvest, Al. 35749 Phone (Work) 205-726-5511 Phone (Home) 205-830-8450. TRAKSAT Satellite Tracking Program Page 65 BIBLIOGRAPHY The following sources were used to prepare and test the TRAKSAT program. Meeus, Jean, ASTRONOMICAL FORMULAE FOR CALCULATORS, 3rd Edition, Willmann-Bell, Inc., Richmond, VA. 1985. Duffett-Smith, Peter, PRACTICAL ASTRONOMY WITH YOUR PERSONAL COMPUTER, Cambridge University Press, New York, NY. 1986. Danby, John, FUNDAMENTALS OF CELESTIAL MECHANICS, 2nd Edition, Willmann-Bell, Inc., Richmond, VA. 1988. Bate-Mueller-White, FUNDAMENTALS OF ASTRODYNAMICS, Dover Publications, Inc. New York, NY. 1971. Forsythe-Malcolm-Moler, COMPUTER METHODS FOR MATHEMATICAL COMPUTATIONS, Prentice-Hall, Inc. Englewood Cliffs, NJ. 1977. USAF-Ford Aerospace Corporation, ORBITAL MECHANICS, O&M Training Section, Sunnyvale, CA. 1982. Moulton, F. R., CELESTIAL MECHANICS, Macmillan Company, New York, NY. 1960. Brand, L., VECTOR ANALYSIS, John Wiley and Sons, New York, NY. 1957. Geyling-Westerman, INTRODUCTION TO ORBITAL MECHANICS, Addison Wesley, Whippany, NJ. 1971. Brouwer, D., "Solution of the Problem of Artificial Satellite Theory without Drag", Astronomical Journal 64, 378-397, November 1959. Hilton, C.G. and Kuhlman, J.R., "Mathematical Models for the Space Defense Center", Philco-Ford Publication No. U-3871, 17-28, November 1966. Hoots, F.R., "A Short, Efficient Analytical Satellite Theory". AIAA Paper No. 80-1659, August 1980. Hoots, F.R., "Theory of the Motion of an Artificial Earth Satellite", accepted for publication in Celestial Mechanics. Hujsak, R.S., "A Restricted Four Body Solution for Resonating Satellites with an Oblate Earth", AIAA Paper No. 79-136, June 1979. Hujsak, R.S. and Hoots, F.R., "Deep Space Perturbations Ephemeris Generation", Aerospace Defense Command Space Computational Center Program Documentation, DCD 8, Section 3, 82-104, September 1977. TRAKSAT Satellite Tracking Program Page 66 Kozai, Y., "The Motion of a Close Earth Satellite", Astronomical Journal 64, 367-377, November 1959. Lane, M.H. and Cranford, K.H., "An Improved Analytical Drag Theory for the Artificial Satellite Problem", AIAA Paper No. 69- 925, August 1969. Lane, M.H., Fitzpatrick, P.M., and Murphy, J.J., "On the Representation of Air Density in Satellite Deceleration Equations by Power Functions with Integral Exponents", Project Space Track Technical Report No. APGC-TDR-62-15, March 1962, Air Force Systems Command, Eglin AFB, FL. Lane, M.H. and Hoots, F.R., "General Perturbations Theories Derived from the 1965 Lane Drag Theory", Project Space Track Report No. 2, December 1979, Aerospace Defense Command, Peterson AFB, CO. Bellman, R. and Kalaba, R.E., "Modern Analytic Computational Methods in Science and Mathematics", American Elsevier Publishing Company, Inc. 1967. Escobal, P.R., "Methods of Orbit Determination", John Wiley and Sons, New York, NY. 1965. Craig, C. John, "Microsoft QuickC Programmer's Toolbox", Microsoft Press, Redmond Washington 1990. El'yasberg, P. E., "Theory of Flight of Artificial Earth Satellites", Israel Program for Scientific Translations Ltd., 1967. (Translated from Russian) King-Hele, Desmond, "Observing Earth Satellites", Van Nostrand Reinhold Co. Inc., 1983.