Dear all,
I have an application where some events in different sites are triggered by the time synchronization taken by the PPS of commercial GNSS receivers. The accuracy of this synchronization should be in the order of 30-35ns.
Can RTK enabled REACH receivers improve this performance (better than Standard positioning)?
Is there any post processing technique of raw measurements (even using IGS data), that can help me to know the sync error between 2 or more REACH receivers (PPS relative error) during the triggering of the event?
Thanks for you support
1 Like
Hi Mirko,
Sorry for the delay, and welcome to the forum!
This setup sounds really interesting and unique! While we don’t have a ready-made solution for something this custom, you can try adapting it based on the RS3’s specs. You can use pin 5 for your setup. If you have any questions along the way, just let me know.
Are you referring to PPS timing accuracy, like the time it takes for the signal to reach your application? According to the datasheet for our navigation module, the time pulse signal accuracy is 99% RMS at 60 ns. If that works for your needs, the receiver should be good to go.
UPD: I’ve revised my reply with the correct timing accuracy.
Hi Inkar,
Thanks for your reply. I meant PPS timing accuracy as the error respect to a common time standard (i.e. UTC or GPST). 30ns @99% RMS is good but not good enough. I have a couple of very technical questions:
1 - Which is the error statistic considering a number of samples taken in 5 consequent minutes? Is it Gaussian (30ns @99%) or should I expect something different? I suppose it is Gaussian in samples taken in a day, but not in few consequent minutes.
2 - If I force to track a specific and same set of satellites by 2 REACH receveirs in 2 different locations, should I expect a correlation between the PPS errors, so that the 2 receivers are better synchronized (than 30ns) between them?
Thanks for your help.
Best regards
Mirko
You probably need something like that:
Massimo
Hi Mirko,
I’ve discussed it with the team, and it turns out the PPS timing accuracy @99% RMS is actually 60ns, not 30ns as I initially mentioned. My apologies for the mix-up!
Since we haven’t specifically tested setups like the one you’re describing in your questions, it’s hard to give you an answer. I agree with @studiodemarchi.net to look into an oscillator.
Hi Inkar,
thanks for your reply. I would need to timetag both position and time with that accuracy, so GPSDO is not the best solution. I wonder if there is correlation of the time error if the two receivers are tracking the same satellites (with a PRN mask).
Best regards
Mirko
Hi Mirko,
In theory, there could be some correlation in the timing errors, but it’s not guaranteed. There are various factors at play, such as the receivers’ internal processes and environmental conditions. Even with the same signal, how each receiver processes it might lead to slight differences in timing accuracy.