Time Stamp Precision Question

So far, I’m getting outstanding results post process correcting the Reach, but I have a question regarding the precision of the time marks. I currently have the Reach rover configured for GPS 10Hz, but when looking at the time marks, they show 1KHz time precision, so not sure exactly how the GPS time is being calculated in the time events file, not sure if the time is pulled from the GPS chip on the Reach or just interpolated to higher precision than the clock cycles, here’s an example:

% GPST latitude(deg) longitude(deg) height(m)
2016/09/01 21:35:32.477 48.111798099 -121.924178297 199.4723
2016/09/01 21:37:22.777 48.110309516 -121.926244348 317.6696
2016/09/01 21:37:23.777 48.110205790 -121.926419437 318.0433
2016/09/01 21:37:24.778 48.110128337 -121.926621785 317.5374

Hi Jeff,

Glad to hear that you are getting great results!

Time stamps are produced by the gnss chip with about 20ns accuracy, so you can rely on them.

Ok thanks, that’s good to know, but being I have the rover configured for a 10Hz sampling rate, is the recorded time in the time events file interpolated between clock cycles to 20ns precision, or is it simply writing out the time and position of the closest rover epoch?

Time is independent from update rate, so it is writing the exact time, not interpolated or tied to close epoch.

Ok thanks, and is the position for each time mark interpolated to that point in time, or is it just pulled from the closest epoch?

Position is interpolated to that time.

Ok awesome, and thank you for being so responsive!

I think I will have some outstanding results to post soon, especially once I can pull the IMU data from the Reach rover.

  • Jeff

Looking forward to see those! :slight_smile: