Raw data writing problem

Q&A forumCategory: QuestionsRaw data writing problem
13vadimka13 asked 2 weeks ago

Hello, everyone! I have a problem with raw data writing for Simplertk2b v1 with original antenna. For this I use SW Maps app. For post-processing I use Rtklib 2.4.3 b33. When I wrote 3 points Ubx 1 hour 1 hz static, I had 1 cm error vs RTK mode. When I wrote 15 minute 1hz Ubx, I didn’t manage to process it properly. I also noticed that in the OBS files only the first L1 frequency is specified, the second one is not. At the same time, I opened in U-center UBX files and saw all frequencies on Sattelite level plot. Although I set all available frequencies and satellite systems in the receiver settings. Files (UBX, OBS, NAV, SBS, POS of rover and base, all RINEX are 1Hz) with measurements of 15 minutes and 1 hour: https://drive.google.com/drive/folders/1ewsxY0os128buRxqcmYcfFkP5Yj1dzT5?usp=sharing. What am I doing wrong? Why does the RTK from this base station work perfectly, but the post processing mode is bad?

13vadimka13 replied 2 weeks ago

I use USB connection with smartphone. Observation files UBX-RXM-RAWX messages USB – on, Navigation files UBX-RXM-SFRBX messages USB – on in U-center

1 Answers
clive1 answered 2 weeks ago

15 min dataset definitely contains L1/L2 data, one here pulled through my RINEX tools, I’m dropping BEIDOU by default, but there are a handful in the dataset B1D1/B2D1
Are you using the RTK Explorer fork of RTKLIB?

13vadimka13 replied 2 weeks ago

Clive1, thank you so much! I solved my problem. I downloaded RTKLIB 2.4.3 demo 5 b33e (http://rtkexplorer.com/downloads/rtklib-code/) and converted all my UBX to L1/L2 RINEX and had fix. No, I used RTKLIB from GitHub.

Why in RTK I have fix all time and in post processing on the same points and rates (1Hz), from the same base stations I have Fix 50-80% of time? Is this due to different processing algorithms in SW Maps and RTKLIB? I wonder if all the calculations in RTK take place in the u blox chip or in a smartphone?

But there is UBX: https://drive.google.com/drive/folders/1s4QMP_AQVc5TIJP1MrL2RsRTtaPVqFpx?usp=sharing, which I couldn’t convert in OBS. What do you think about it?

clive1 replied 2 weeks ago

The RTK solution is developed inside the ZED receiver, SW Maps is just reporting the NMEA output provided by the receiver.

I suspect the receiver has more people working on it, who bring decades of experience with them. You should perhaps try professional post-processing tools.

13vadimka13 replied 2 weeks ago

Clive1, thank you! I will rty