[Kstars-devel] SatLIb verification

[Bernard GODARD]

Hi,

I did a comparison of SatLib with heavens above and PREDICT on the
2007 april 29 19h40 UTC pass of the ENVISAT satellite above Toulouse
(France) :
- the differences from SatLib and Predict on 8 points along the pass
are less than 1 degrees
 in both altitude and azimuth
- the differences between heavens-above and SatLib are more pronounced :
_________________________________________________
HEAVENS ABOVE
_________________________________________________
Event	                            Time	   Altitude 	Azimuth
Reaches 10° altitude 	        21:41:52 	10° 	87° (E ) 	
Leaves shadow 	                21:41:02 	8° 	95° (E ) 	
Maximum altitude 	        21:44:23 	14° 	58° (ENE) 	
Drops below 10° altitude      21:46:54 	      10° 	28° (NNE) 	
Sets 	                              21:50:21 	      0° 	4° (N ) 	
_________________________________________________
SATLIB
_________________________________________________
Event	                             Time	   Altitude 	Azimuth 	
Reaches 10° altitude 	        21:43:22 	10° 	71° (E ) 	
Leaves shadow 	                21:40:57 	5° 	93° (E ) 	
Maximum altitude 	        21:44:43 	11° 	55° (ENE) 	
Drops below 10° altitude      21:46:02 	      10° 	40° (NNE) 	
Sets 	                              21:50:17   	0° 	6° (N )
__________________________________________________

The ENVISAT TLE used with Predict, SatLib and Heavens-Above was the same:
ENVISAT
1 27386U 02009A   07118.76468073  .00000023  00000-0  24704-4 0  6392
2 27386 098.5492 186.3684 0001106 104.6779 255.4513 14.32247138269785

Toulouse latitude, longitude, altitude used with all programs :
 43.6deg
 1.433deg
 136m

I will try to find the time to do a few other tests.

Clear skies

      Bernard



On 4/25/07, JB BUTET <ashashiwa at wanadoo.fr> wrote:
> Hi
>
> Ok, with good TLEs it seems there's a pb.
> I have another program (in dos, really accurate) for satellites to verify.
>
> > Anyway, my original question was: have you done any verification of the SatLIb
> > predictions against other published satellite predictions?  If so, can you
> > tell me about the results and which sources you used for the comparison?
>
> I've ported satlib in order to make some predictions abou ISS. So I've
> done ISS comparison with heavens-above and ...m don't remember this
> great site... mmm... ah... no more neurons left here... calsky !!
>
> And errors was really minimal. (predictions were good).
>
> But I haven't try for others.
>
> May be Patrick or Bernard has some other ideas ?
>
> Clear skies,
>
> JB
>
>