Raw data writing problem

Q&A forumCategory: QuestionsRaw data writing problem
13vadimka13 asked 2 years 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?
replied 2 years 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 years 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?
replied 2 years 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?

replied 2 years 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.

replied 2 years ago

Clive1, thank you! I will rty

Want to learn more about GPS/RTK?

1. Our engineering team will contact you to solve any questions
2. We will keep you updated about promotions and new product releases
3.You will only hear from us when we have important news, we won’t spam your email