Re: Positional Requirements

Rainer Kracht (R.Kracht@t-online.de)
Mon, 27 May 96 00:50 +0100

>Date: Sun, 26 May 96 18:47:51 PDT
>From: Leo Barhorst <leobarhorst@pi.net>
>Subject: Re: Positional Requirements
>To: seesat-l@iris01.plasma.mpe-garching.mpg.de

>Like RB Minton, Ron Lee and Lutz Schindler I'm also interested in pro-
>grams calculating elements from positional measurements.

And there is also Paul Maley, who wants to derive elements from his video
observations.

I have made such a program to derive standard magnitudes from pairs of
Russell's observations, but it was a little complicated to use. I have
now modified this program, so that it is more easy to use. 

The main point was to change the input format to that used by Mike's
FITELEM.EXE program. The same input format is used by Mike's version
of ELCOR.EXE.

I will sent an self-extracting archive named FIRSTORB.EXE to Neil
Clifford for his ftp://ftp.physics.ox.ac.uk/pub/sat/programs/ibmpc 
directory.

Unpacking of FIRSTORB.EXE should give three files:

1. FIRST.TXT this message
2. FIRST.EXE 
3. INPUT

FIRST.EXE will read INPUT and generate a file OUTPUT with a two line
element set from the two observations in INPUT.

EXAMPLE:

file INPUT
observed magnitudes are at the end of the lines with observations
(first obs mag 6.8, second obs mag 8.3)
----------------------------------------------------------------------
    5
   38.9478  104.5614     6801.    Ron Lee          
   43.6877   79.3927      707.    Ted Molczan
   47.8033   -7.3417      705.    Daniel Karcher
   29.5378   95.0868       30.    Paul Maley
   55.9486    3.1383      141.    Russell Eberst
96-29A        
1 23862U 96029  A 00000.00000000  .00000000  00000-0  00000-0 0    00
2 23862 000.0000 000.0000 0000010 000.0000 000.0000 00.00000000    00
  5 96  5 24  1  9 48.2  19 18.12  -2.601 1950 6.8
  5 96  5 24  1 14 28.8  22 38.88  22.554 1950 8.3
  0  0

----------------------------------------------------------------------

SCREEN OUTPUT
----------------------------------------------------------------------


    period        108.0071 minutes          n = 13.3325 rev/day
    height       1133 km                    R.A.A.N. = 240.1126 deg
    inclination    63.2407 deg              t0 = 96145.037972

                     range       phase
    first obs       2103 km      51.1 deg
    second obs      2229 km     105.9 deg

    standard magnitude (1000 km, 90 deg) from both obs    6.0

    <ENTER>

----------------------------------------------------------------------


file OUTPUT
----------------------------------------------------------------------
    5
   38.9478  104.5614     6801.    Ron Lee          
   43.6877   79.3927      707.    Ted Molczan
   47.8033   -7.3417      705.    Daniel Karcher
   29.5378   95.0868       30.    Paul Maley
   55.9486    3.1383      141.    Russell Eberst
96-29A                          6.0
1 23862U 96029  A 96145.03797153  .00000000  00000-0  00000-0 0    00
2 23862  63.2407 240.1126 0000010   0.0000   0.0000 13.33245561    00
  5 96  5 24  1  9 48.2  19 18.12  -2.601 1950 6.8
  5 96  5 24  1 14 28.8  22 38.88  22.554 1950 8.3
  0  0
----------------------------------------------------------------------

This OUTPUT file can be used as INPUT for ELCOR. ELCOR will improve
the orbit, because my FIRST program uses only very simple approximations
for the perturbations of the orbit.

Starting ELCOR with: ELCOR OUTPUT

and 

0 BSTAR
1 inclination
2 R.A. Asc. Node
3 eccentricity
4 arg of perigee
5 quasi mean anomaly
6 mean motion
Which ones to refine (up to 4):1 2 5 6

gives (after few iterations):

BSTAR [0.0000e+000]:
inclination [63.2168]:
R.A. Asc. Node [240.0424]:
eccentricity [0.0000010]:
arg of perigee [0.0000]:
quasi mean anomaly [0.1243]:
mean motion [13.32396599]:
mean anomaly 0.1243


With these elements, FITELEM has:

----------------------------------------------------------------------
    5
   38.9478  104.5614     6801.    Ron Lee          
   43.6877   79.3927      707.    Ted Molczan
   47.8033   -7.3417      705.    Daniel Karcher
   29.5378   95.0868       30.    Paul Maley
   55.9486    3.1383      141.    Russell Eberst
96-29A                          6.0
1 23862U 96029  A 96145.03797153  .00000000  00000-0  00000+0 0    09
2 23862  63.2168 240.0424 0000010    .0000    .1243 13.32396599    06
  5 96  5 24  1  9 48.2  19 18.12  -2.601 1950 6.8
  5 96  5 24  1 14 28.8  22 38.88  22.554 1950 8.3
  0  0

 5145  1 9 48.2    .0 19 18.13 -2.603 19 18.12 -2.601 -.002  .002  .003
 5145  114 28.8    .0 22 38.88 22.557 22 38.88 22.554  .001 -.003  .003
----------------------------------------------------------------------

Now additional observations can be used to refine the orbit.


 Rainer Kracht  1996 May 26
 R.Kracht@t-online.de
 +9.6626E, +53.7695N, 9m