[FOSS-GPS] High accuracy positioning with low cost GPS devices:a FOSS project

ttakasu ttaka at yk.rim.or.jp
Wed May 6 16:55:48 EDT 2009


Hello Eugenio and Jaykob

>>Do you have any idea about how to handle these time-tag issue?

Time-tag difference between receivers has usually no problem
because the satellite clock is highly stable.

By satellite-side single-difference, receiver clock error,
is perfectly canceled if the receiver inter-channel bias is
zero.

Concerning receiver-side single-difference, the difference
of the signal reception time (strictly, the difference of
transmission time) brings slight error mainly due to satellite
clock drift (and atmospheric effect, orbit error). But in a few
seconds, usually it is negligible in the current SA terminated
condition.

So time-tag adjustment is possible but not necessary for
usual relative positioning process.

T.Takasu
http://gpspp.sakura.ne.jp/indexe.html


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