This doesn’t surprise me. Some years back I thought I could get better PPS
resolution from a survey grade receiver but was disappointed to find on looking
at specs of those available that PPS performance was generally worse than
timing receivers, which of couse were much cheaper. It’s a no brainer now with
sawtooth error correction available.
> Le 21 déc. 2018 à 05:05, Mark Sims a écrit :
>
> I recently got in a Trimble NetRS L1/L2/L2C survey grade receiver (Evil Uncle
> Bob made me do it ;-) ). It consistently gives position error ellipses in
> the 6mm range after post-processing 24 hours of data.
>
> I had high hopes it would have a decent 1PPS output... nope. The PPS output
> usually has a 40 nsec span (looks like a 25 MHz clock is in the device), with
> some occasional 80 nsec or so spans. The internal oscillator looks to be an
> OCXO... the PPS does not show your typical wobbly PPS sawtooth error plots.
> It is more like a pulse train with a slowly drifting duty cycle.
>
> But the killer is the occasional (2-3 times per hour) "zingers" in the PPS
> output. These show up as a large negative error spike followed immediately
> by an equal positive errors. These "zingers" are typically in the 1-100
> millisecond range. I can't imagine how/why the circuitry would do this...
>
> Lady Heather can now monitor the NetRS (and probably other receivers that can
> output RT17 and Trimcomm data. The NetRS does not respond to requests for
> status and configuration commands over the RT17 ports, so a lot of
> useful/informative stuff is not available. It can write RINEX
> files.___
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