Re: Statistics on prediction accuracies

From: George Roberts (gr@gr5.org)
Date: Fri Apr 08 2011 - 03:52:22 UTC

  • Next message: Marco Langbroek: "Re: Statistics on prediction accuracies"

    I would say 99% of the TLEs are within 0.1 seconds and 0.1 degree position 
    cross track.
    
    The ones of low objects (experiencing less predictable drag) that are more 
    than a month old are the ones that are suspicious.  Each TLE has an epoch 
    and almost always the epoch is set to the moment of the most recent 
    observation that went into it or when the orbit was recalculated.  So if the 
    TLE has an epoch more than a month old and if the orbit is less more than 
    say 10 revolutions per day (the final number) then it could easily be off by 
    30 seconds.
    
    All the orbits from sattrack are spot on.
    
    In heavens above you can click on the satellite, then click oribt to see its 
    orbital elements and see how old the elements are.
    
    - George Roberts
    http://gr5.org
    -----Original Message----- 
    From: Frank@reednavigation.com
    Sent: Thursday, April 07, 2011 8:09 PM
    To: seesat-l@satobs.org
    Subject: Statistics on prediction accuracies
    
    Hello all.
    
    I haven't posted to SeeSat-L in some years. I'm looking for any information 
    on the accuracy of predictions for bright satellites (brighter than 
    magnitude 3.0). What are normal expectations, both in terms of timing and 
    angular position using standard, widely-available sources (e.g. 
    heavens-above.com)? Also is there any dataset that identifies 
    non-maneuvering satellites? If I go through TLEs for the past couple of 
    years, is there some easy way to identify "live" satellites? Climbing to a 
    higher altitude seems like a safe bet.
    
    Frank Reed
    Chicago, Illinois
    
    
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