Hi, all Not sure if this is 100% within scope of the list, but still: I am trying to get some good stability measurements of my hydrogen maser, using GPS L1/L2 and PPP. I collect L1/L2 code and phase observables continously, and process daily RINEX-files with PPP software and IGS corrections.
I've used the NrCAN-PPP online service, which gives reasonably good results. The issue with NrCAN is that it only process in the forward direction (at least, this is what I assume, looking at the results.) So I want to run the processing locally so that I can run it both forward and reverse. I have not been able to get a copy of the nrcan-ppp softwarepackage, so I am looking elsewhere. ESA gLAB looks like it might fit the bill. The problem, in short, is that the data I get from postprocessing with gLAB is much, _much_ noisier than the results I get from submitting the RINEX files to NrCAN-PPP online service. (see attached screenshot - note I've cut away the first 2-3 hours of noisy data from nrcan) I've tested this on both a Trimble NetRS and a Novatel OEMV3, and I get comparable results from both: nice smooth data from NrCAN (except the first 2-3 hours), jagged noisy data from gLAB. (The Novatel required jumping through MANY hoops before I could get any usable data, including writing a RINEX-converter. In case someone wants to play along..) I'd be tempted to think NrCAN applies smoothing somewhere, but the .sum file contains "Parameter smoothing: NO" I am running gLAB with 5-second interval observations, IGS Rapid products (*.sp3, 10 degree clock interpolation), forward/reverse, throw away the forward, grab clock offset from the FILTER output, convert to ns - as A. Wallin is doing in ppp-tools. So, in summary; does anyone know what is going on? Am I missing some step in the gLAB processing? Thanks for any insight. Ole [image: Inline image 1]
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