Re: unid

From: b_gimle@algonet.se
Date: Tue Jul 19 2005 - 10:29:58 EDT

  • Next message: Ted Molczan: "RE: unid"

    I was too busy to help Ed on the 20050702 UnId, but a few days later I 
    let
    ElObsEnt vary a few elements, then finally all but BStar, and found
    2 99999  25.3383 185.6351 3419087  85.9997  81.0203  5.27711595    50
    
    Same procedure on 20050716 gave
    2 98765  27.7631 187.1211 4255435 136.9730 113.3469  6.16127792    00
    
    Description of 2-line elements: http://www.satobs.org/element.html
    
    Looking at RAAN (and i + AOP?) they were possibly the same object.
    If MM is near 6 (or 5,4,3,2) orbits/day (84 orbits/14 days), it might be 
    about 4 minutes early each day, but it could also have made 83, 82...
    ... 28 or even fewer orbits! 
    This "red herring" led me to test this in ElObsEnt, with RMS errors:
    RMS=1.96 85 orbits MM=6.08993
    RMS=1.83 84 orbits MM=6.01828
    RMS=1.67 81 orbits MM=5.80334
    RMS=1.63 80 orbits MM=5.73171
    RMS=1.60 79 orbits MM=5.66008
    RMS=1.54 78 orbits MM=5.58843
    RMS=1.50 77 orbits MM=5.51679
    RMS=1.46 76 orbits MM=5.44516
    RMS=1.42 75 orbits MM=5.37353
    RMS=1.32 72 orbits MM=5.15865
    RMS=1.28 71 orbits MM=5.08703
    RMS=1.24 70 orbits MM=5.01542
    RMS=1.13 67 orbits MM=4.80071
    RMS=1.03 64 orbits MM=4.58751
    RMS=1.00 63 orbits MM=4.51999
    RMS=0.96 62 orbits MM=4.44709
    and I finally gave up and tried MM=2.0x, which I should have done first!
    RMS=0.38 28 orbits MM=2.07802
    
    Removing his most uncertain point I finally had RMS=0.36 degrees:
    Ed050716 28 RMS=0.36
    1 98765U 05697A   05197.07504393  .00000011  00000-0  91738-3 0    20
    2 98765  27.7205 194.2213 7187947 127.7817 277.7445  2.07801689    60
    
    The observations I used:
    98765 05 697A   9730 P 20050716041348500 17 35 1924500+165000 17 S+060 
    03
    98765 05 697A   9730 P 20050716041405500 17 35 1936300+163000 17 S+060 03
    98765 05 697A   9730 P 20050716041452800 17 35 2014280+152000 17 S+060 
    03
    98765 05 697A   9730 P 20050716041519500 17 35 2034850+140000 17 S+060 03
    98765 05 697A   9730 P 20050716041547500 17 35 2055690+132000 17 S+060 
    03
    98888 05 697A   9730 P 20050716041613500 17 35 2112000+128000 57 E+990 01
    98765 00 000B   0002 G 20050702051358500 17 25 1606000+100000 38 S
    98765 00 000B   0002 G 20050702051451800 17 25 1633000+103000 38 S
    98765 00 000B   0002 G 20050702051553500 17 25 1705000+120000 38 S
    98765 00 000B   0002 G 20050702051645500 17 25 1739000+131800 38 S
    
    What these numbers mean: http://www.algonet.se/~b_gimle/IODprograms.htm
    (Station ID 0002 and 9730 are identical in my ELMASTER file)
    
    /Björn
    
     
    ----- Original Message ----- 
    From: "Ed Cannon" 
    ...
    > may have clicked a couple of seconds late due to not realizing 
    > it immediately, and I may have underestimated the uncertainty 
    > of that position.  Station 9730 is BCRC: 30.315N, 97.866W, 280m.
    > 
    > For what they might be worth, here are positions in IOD format
    > (with 98765 being completely arbitrary of course, and 05-697A
    > being day 197 plus 500, object A, of this year):
    
    
    -- What the above numbers mean: www.algonet.se/~b_gimle/IODprograms.htm --
    /Björn
    
    -- COSPAR 5919, MALMA,    59.2615 N, 18.6206 E, 33 m         --
    -- COSPAR 5918, HAMMARBY, 59.2985 N, 18.1045 E, 44 m         --
    
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Tue Jul 19 2005 - 10:45:01 EDT