Re: mmccants tles and sattrack.

From: Ralph McConahy (rmcconahy@earthlink.net)
Date: Fri Mar 15 2002 - 00:53:58 EST

  • Next message: Vladimir Agapov: "Re: UFO 9 (USA-140)"

    Atul Sowani wrote:
    
    > When I use tles downloaded from mmccant's site with SatTrack,
    > I am getting "checksum error in line[2]" for all satellites.
    
    Can't help with the error you are getting, but I can answer your question...
    > What is "checksum" and how it is calculated?
    
    The checksum digit is the last digit on the TLE.
    Example:
    TRMM
    1 25063U 97074A   02073.54250259  .00066661  00000-0  92646-3 0  5707
    2 25063  34.9757 236.9292 0000682 267.5731  92.5406 15.55953514246813
    
    The checksum for the first line is "7", and "3" for the second line.
    
    It is calculated by adding the digits of the first 68 characters, modulo 10
    (the checksum digit is in column 69). For non-numbers: Blanks, letters,
    decimal points and "+" each equal zero, the minus sign ("-") equals one. In
    the first line above, adding the digits (don't add the 7 on the end), and
    remembering to add one for each "-", you get 157 (157 modulo 10 = 7). For
    the second line you get 223 (223 modulo 10 = 3).
    
      Ralph McConahy
      34.8829N  117.0064  670m
    
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Fri Mar 15 2002 - 00:55:06 EST