Okay, after I received a couple of e-mails pointing towards software bugs, and position in-accuracies,
I decided to put up this page with comparing results of the various programs available for free. These
include STK, HOMEPLANET 3.0, MyStars, GPS, LinSat, Trakstar v2.53, Trakstar v5.65 etc. All together 25
tracking programs.
As for the sites please read the comments since I could not put my test.tle up and
thus I had to use a different date, and TLE.
To get a simple yet meaningfull testcase I was thinking that the satellite in question should be in inclined orbit, it should have a high eccentricity and the date should be set to 1999 or before, in order to avoid a possible Y2K - bug which some older progs might still have. So I used an old TLE I found of Oscar from 1996. Then I was looking for a point fairly close to earth, so the satellite has a high velocity to make differences more obvious. (Note that the date might change later if my current starting date is no good).
Here is the TLE I found :
OSCAR 10
1 14129U 83058B 96226.26539988 -.00000182 00000-0 10000-3 0 4469
2 14129 26.0187 194.8640 6028317 39.9473 351.5269 2.05882799 71040
Download the TLE here
As date I picked : August 14'th 1996 (DayOfYear=227) at 7:50:00
which is about one day after epoche.
If not stated otherwise all programs use the WGS84 Spheroid model, J2000 reference datum and the SGP4/SDP4 algorithms to calculate the position of the satellite. The units are in Km, and degree.
The Color code is as follows :
| Red | Orange | Yellow | Green | Purple | Blue | White |
| > ±15% | < ±15% | < ±10% | < ±5% | < ±3% | < ±1% | < ±0.1% |
Find here what the results are :
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(Open Source) |
This program was derived from Dr. TS Kelsos Pascal code. The code was cleaned up slightly and it was tried to resolve all bugs etc. | This is the program used for reference, thus there is no delta. | ||||||
| 26.568,8 ±0.0 |
02.280,10 ±0.0 |
02.191,63 ±0.0 |
4,70587N ±0.0 |
75,6099W ±0.0 |
20.378,4 ±0.0 |
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(Open Source) |
This program was derived from my C++ version of GPS. It is a JavaScript implementation of the code with a 'easy to use' graphical front end. | Since it is based on the same code only converted to Javascript, the resulats ought to be identical. | ||||||
| 26.568,8 ±0.0 |
02.280,10 ±0.0 |
02.191,63 ±0.0 |
4,70587N ±0.0 |
75,6099W ±0.0 |
20.378,4 ±0.0 |
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(Open Source) |
This program is derived from GPS, thus using the same code for calculating the position. It even has the same author ;-) | The results to GPS should be exactly the same since it is using the same DLL. | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
2.65 (2000-Jan-22) (Free) |
This is the most current version of Dr. TS. Kelsos Pascal program. It was modified to be Y2K compliant. GPS should have all the changes that comes along with this release already incorporated. The results differ though. | I scaled down the precision of GPS, to avoid typing in huge numbers with no real meaning. This accounts for most of the measured error. | ||||||
| 26.568,88 -0.08 |
2.280,089 0.011 |
2.191,646 -0.016 |
4,7059N -0.00003o |
75,61W -0.0001o |
20.378,456 -0.056 |
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2.15 (1992-Oct-01) (Free) |
This is a version which had not yet the Y2K modifications included. This was the basis for my program GPS v1.0. | I just wanted to see if I do get exactly the same results. Since I took a date before Y2K, I am not surprised that I do ! | ||||||
| 26.568,88 -0.08 |
2.280,089 0.011 |
2.191,646 -0.016 |
4.70583N -0.00007o |
75.61W -0.0001o |
20.378,456 -0.056 |
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3.1 (free) |
About the program | Comments | ||||||
| X | Y | Z | 25.11N | 37.17E | 4742.4 | |||
| Satellite Orbit Analysis Program (SOAP) Version 11.80 (Licenses no longer avail ???) | About the program | Thanks John Coggi from the SOAP development team for providing these numbers. | ||||||
| 26568.889 +0.089 |
2280.0894 +0.0106 |
2191.6466 -0.0166 |
4.70589N -0.00002o |
75.6100W -0.0001o |
20378.463 -0.063o |
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| LogSat Professional for Windows Version 5.2 (69.95$) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Track16 (freeware) | Freeware from Jim Varney | Simple and easy to use 16 Bit Windows applicatoin without graphics output. | ||||||
| NA | NA | NA | 4,7059N -0.00003o |
75,61W -0.0001o |
20378 +0.4 |
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| Nova for Windows 32 Version 2.0j ($59.95) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Orbit Version 1.1 ($23.00) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| OrbMaster 2.0 ($59.95)-> No longer available | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| OrbSat Version 1 (Open Source) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Sat Spy Version 2.0 (Out Of Business) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Satellite Hunting Version 2.0.3 (Shareware for a month) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Satellite Tool Kit (STK) Version 4.1 (free CD-ROM) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Satellite Tracker Version 2.1.2 (20.00$) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| SatScape Version 1.85 (Maybe free ?) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| SkyChart III Release 3.2 ($49.95) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Starry Night Version 3.1 (29.95$ - 129.95$) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| WinOrbit Version 2.9 (Freeware) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| WinTrak Pro Version 4.07 ($49.95) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| WXtrack Version 3.0.0 (freeware) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| TRAKSAT Version 4.09 ($25.00) | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
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| J-Track Satellite Tracking | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| J-Pass Satellite asses | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| J-Track 3D | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
| Heavens-Above | About the program | Comments | ||||||
| X | Y | Z | Lat | Lon | Alt | |||
Conclusion :
Later ...