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Re: Parise MIR KEPS



Regarding the NASA TLE checksum method, Paul, KB5MU wrote:
 
> It doesn't notice transposition of digits, it's easy to make compensating
> errors, and even if you type in random garbage the check digit will
> match 10% of the time.  Very poor design.

However, you can check for things like a 'U' in the 8th column of the
first line, the length of each line, decimal points and blanks that always
appear in certain columns, and the '1' and '2' in the first column of
the first and second lines to help distinguish a valid two-line element
set from something else that might pass through based on a checksum
calculation alone.

Granted, it's not as robust as having a CRC to work with, but the extra
checks help to prevent extraneous text from "slipping by the goalie".  :-)


73, de John, KD2BD

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