Hello all!
I am trying to get a fix solution for 16 points I collected using the stop and go PPK method.
I have attached a link to the the observation files of the base, rover and rinex files from the local NTRIP provider. I have also included the .csv file of the GCPs collected in the field.
Here is the link to the files: Unique Download Link | WeTransfer
Any help is VERY appreciated!!!
Andrew
Did you try some of the past suggestions and TOPAZ?
Hi.
I’ve had a look, and managed to get 11 fixed and the rest on float. Files attached.
Issues I think you are having:
The base file and rover files didn’t properly overlap. I downloaded the additional data for the base, combined file attached.
Base is 30 secs rate, baseline is 30Km and log duration on each point is 10 secs. That is nowhere near enough at that length and the base line is pretty big so overall accuracy is diminished. You would need to have much higher rate and longer static periods.
The rover file had a quite a few cycle slips which probably isn’t helping. Not sure what your terrain was there but trees etc would not be helping your cause.
A further thing I think is the file was logged in static. I tried taking it into another software but it had no kinematic data so could only load in as static. I’m not sure how to get around that. Studio and stop and go was working fine.
I had to play about with settings a bit to get 68% fix.
Results.zip (4.9 MB)
Cheers
Scott
Thanks for the comments and observations!
The slips are no doubt due to me putting the GPS in the car and driving between GCPs.
The best solution I have got at this stage is 30% fix which results in 9 of the 16 GCPs in fix. The setting I used were:
Path: One best
Combined
GPS and Galileo
GPS fix and Hold on Glonass
SNR Mask 35
Regarding the Kinematic or static mode, it is my understanding that the R3 unit is only collects Kinematic mode (I hope I have correctly understood your comment here).
Used to be able to select STATIC or KINEMATIC in prior versions. Emlid said it doesn’t matter, so now only KINEMATIC is selectable… but personally, i think it just confuses users more.
Honestly, at the cost of Emlid receivers there’s no excuse to have an extra receiver logging static data onsite. I get calls all the time from people that don’t understand GNSS measurement methodology trying to PP 5 minutes of data logging at 30 seconds with a CORS more than 30km away.
Use the extra receiver logging at a minimum of 1 second rate or faster if using drones. Then collect your data with the rover at the same rate as the base receiver. You can then PP your data in the office using Emlid Studio. Even if you are using local Lora RTK or an RTN service, it’s good to have the data to PP with to verify questionable RTK positions.
Also log enough data to PP with at the rover !
I see, I’ve not had hands on the RS3 so wasn’t aware there was a change to those options. My apologies. Even so, if kinematic, there should be a marker and start site header section within the log file for each occupation?
Like so from a RS2+ file:
For studio this is maybe redundant but other software will use these to split up the stop and go segments. Is that now missing from the RS3 rinex files? Interesting if it is. I only noticed as I took it into carlson to run it there as a check to see if there was an improvement but came in as one block which was strange for a stop and go kinematic file.
Hi Scott.
You’re right, I didn´t included the NTRIP OBS for the period 13:00-14:00.
I still can´t replicate you’re results though. I only get 9 of the 16 points in Fix. In fact, the best results I get are with using only GPS satellites.
I’ve included ALL the files necesarry this time, hoping that someone else might be able to give it a try.
Many thanks!
Hi Andrew
I fiddled with masks to try and increase the percentage of fixed and used the combined filter option. The settings are up in the screenshot above.
Further tweaking may increase the fixes but I’d be suspicious of the results. The baseline length and short recording on each location means there is at best one time match and the rest is interpolation by the software. The baseline length also means that there are inbuilt errors which propagate over increased distance (your ppm in the specs). As a result the software may say fixed but the uncertainty of that fix is pretty high. Ideally you would have a local base and high rate logs for the rover. Your other option is to have a virtual station generated and use that. I’ve not got that function but maybe someone can assist for you. A few softwares offer trials so you may get a chance to generate the vrs using a trial. Such as leica spider, Trimble or carlson gnss. There will be more options but I’ve not got much experience with those as it’s not something I’ve ever needed to have in the kit locker.
Best of luck, hopefully someone can assist further.
Scott
Hi Andrew,
Sorry for my late answer here.
I’ve checked your raw data, and the rover logs indeed have some cycle slips, which can affect the final result of the post-processing. Also, I can agree with Bryan that having your own base, and thus a shorter baseline, can improve the results.
Can you please share your CSV file with me so that I can also check the Stop&Go in Emlid Studio?
Speaking of the Kinematic mode, starting from firmware version 31, the Static mode is indeed removed from the GNSS settings for RTK and multi-band units. Our tests show that the results don’t differ much from Kinematic.
Hi Kornel,
Thanks for getting back to me.
Here are the GCPs.
villar gcps.zip (1.5 KB)
Let me know if you need anything else.
Cheers!
Hi Andrew,
Thank you!
I’ve also tried the Stop&Go with your dataset. The best I could achieve was 12 points FIX out of 16, with the remaining 4 being FLOAT. I got this result using a Combined filter, an Elevation mask of 30 degrees and an SNR mask of 35 for both L1 and L2.
As I previously mentioned, good raw data quality is essentially required to get everything FIX after post-processing. Playing with the settings may improve the results, but it may not be able to resolve everything.
Hi Kornel,
Thanks for following that up! It’s greatly appreciated.
I’ll give it a shot and see how I go.
Andrew,
Sure! If any further questions occur, feel free to drop a comment.
Hi Kornel,
Another query:
Instead of using the IGN base which was located 30kms away, I have the coordinates of the base unit:
Coordinates (ETRS89 Huso 30)
X: 165777.631
Y: 4340833.927
Z: 247.158
The best results I get are using the following settings:
Filter: combined
Elevation mask: 25
Satel: GPS and Galileo
Integer: Fix and Hold
SNR Mask 35 and 35
However, The question I have here is how do I enter the UTM coordinates into the known base position along with the height from the geoid model? I need points to be exported in UTM coordinates and the Geoid heights.
A
Hi Andrew,
In Emlid Flow, it’s possible to configure your base’s position using any point from your projects. This way, you can use this point with the UTM coordinates if it’s saved to any of your projects. After doing so with the help of this Support tip, you’ll see the base’s coordinates in geographic coordinates in Emlid Flow.
Later in Emlid Studio, you can use these coordinates to add the base position for PPK manually. Still, the corrected CSV will contain the geographic coordinates of the points.
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