Hi,
Does anyone use L1/L2 receiver using the stop'n go method?
I used the Sokkia GSR2700ISX with the SDR+ and stop'n go method to see if I get good results.
I measured 17 points and then downloaded a RINEX file of a VRS to use it as a base.
All points was occupied for 5 seconds(epochs) without any initialization time. Also in the middle of the survey I forced the receiver to lost tracking of satellites to see if the points after that time was float instead of fixed.
Unlike L1 only GPS-GNSS systems all of the points were fixed. Compared to the same 17 points occupied with RTK the differences were under 1-2 cm.
I liked the results and I think this is a good alternative in case there is no cellular network available for RTK measurements.
What is your opinion on this?
I use S&G sometimes, works perfectly fine. The ONLY advantage RTK of any flavor has is knowing real time that a given occupation is likely going to be OK, same signals, same hardware, just a post processed solution rather than a real time one. Of course stakeout doesn't work, but for gathering topo there really should be very little difference at the end of the day. The disadvantage of course is it takes more experience to know that what you are doing in the field is going to produce acceptable results when you get back to the office.
S&G is just another tool, learn it and use it when you need to.
SHG
A practical problemn I have found with this is that when there is no cell signal, you are normally to far away from a vrs base to get a decent solution. Most of the. Vrs bases seem to be placed in places to get optimum use, not out in the middle of nowhere where there is no cell signal.
I'm new to RTK, but I've been recording a file at the base and rover and on critical work, like boundaries and control for boundaries, for a few months. I do this to verify the RTK results with post-processing. The base file is recorded at ten second intervals, the rover at one. The base file gets sent to OPUS. Dual frequency, stop and go reinitializes quickly. The kinds of shots I'm proofing are three or more minutes in duration, which has been plenty to get fixed solutions. My processor is Ashtech's GNSS Solutions (the most affordable package I'm aware of - and functional). I have to create a "D" file from the rw5 file produced from the Carlson data collector we use. The GPS files are RINEX, GPS plus GLONASS. Solutions is able to interpolate the ten second data at the base to solve the one second epochs at the rover. I use "Compare Points" in Carlson to see how the points compare between PPK and RTK. If everything looks withing spec, I stick with the RTK.
Keeping a post process file practically allows you to remeasure every point in the job even years after the fact. Kind of cool, and doesn't "cost" anything extra to do.
Why Only 5 Seconds?
It takes at least twice as long to input a decent occupation point description. Curb or ground shots are one thing, but anything worth an actual description deserves more time.
Paul in PA
Why Only 5 Seconds?
I did that just for testing.
Probably 10 or 15 seconds is better occupation time.
I've found with the Topcon Legacy running in fast static mode, that a 60 second occupation results in residuals of less than 0.02', compared to S&G Leica dual phase observations, once batched through OPUS.
This was two entirely separate units, using NGS established monumentation for the base units.