[GPS_Standard] GPS Jitter.

[Stig Kristiansen - OZ3XO.]

The Trimble Resolution T receiver outputs a 1 Pulse-per-second (PPS) timing.signal accurate to within 15 nanoseconds of GPS or UTC (1.sigma) when using an over determined solution in a stationary mode.

<5 ns with quantization error removed.

The Trimble Resolution T goes Automatically into fixed position timing mode after is has performed a default self-survey by averaging 2000 position fixes (2000 sec.) but is user selectable from 1 to 2e32-1.

So the jitter of the PIC has en effect, but since the timing is evaluated over 32 Sec. so the problem is then reduced to 16,625 ns, as 1 / (( 8.000.000 Hz * 32 sec ) / 4 instructions ), and this will just be equal to the GPS, so if the PIC evaluation time was just 10 times higher, then the jitter will just be 2 almost times better, but this it already been done, by accumulation of the PIC counter over longer time.

So I guess this will be about the best it can get, and we also has to make sure that we are not aiming higher that really needed for our applications, as SSB or even narrowband data on 10 GHz or higher can be done with out any problem, so what do we really need it for, or will it just be to tell others that we are more accurate the your friends, and if so, then the GPS signal might even not be the way to do this, and I think me just have to thing about what will generate our needs.

Stig - OZ3XO.