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SimpleRTK2B-lite as basestation correction problem

Q&A forumCategory: QuestionsSimpleRTK2B-lite as basestation correction problem
PK asked 6 months ago
Hi,
I have configured SimpleRTKB-lite as basestation and sending RTCM3 messages through UART1.Then i use RTKlib strsvr to route RTCM messages to rtk2go.com server. Everything works great at rover and i get fast fix posion but after few minutes rover goes to single mode. When in single mode rover still receives RTCM messages from basestation, but wont get float or fixed postion. Then i go to u-center and hotstart basestation. Rover will immediately start to float and fix. Same thing happens when i use u-center build in Ntrip caster. I have tested rover with Leica smartnet and it works normally with that. Any ideas how to solve this?

2 Answers
clive1 answered 6 months ago

> Any ideas how to solve this?

Try to determine what mode the Base Station is in when this issue is observed.
Is it throwing any warning or error messages, look for $GxTXT like output?
Outputting what RTCM 3.x messages at the time of failure?
What firmware is it running?
Got any data logged from the Base in this condition?

PK
replied 6 months ago

Basestation is in time mode hole time and outputs RTCM 1005,1074,1084,1094 and 1230 messages. I checked it with rtklib RTKnavi. Firmware is latest 1.13 and i have flashed it couple of times but it has no effect on the issue. There is warning message in GNTXT when i power on basestation or restarted it (hotstart). First it reads “Starting GNSS” and couple of seconds later “Warning unknown error”.

clive1
replied 6 months ago

Is that an error coming from the receiver itself of the RTKLIB / RTKNavi application?
It shouldn’t necessary to reflash the receiver, if the firmware is corrupt, it won’t run and you’ll get some different messages entirely.

PK
replied 6 months ago

Coming from the receiver when i look Message view in u-center. I use RTKnavi only to see RTCM feed from rtk2go.com. Receiver is not connected to RTKnavi. I did depug messages on u-center but all the messages where same at the time of failure. Is it possible to configure the receiver to automatically hotstart every x time?

clive1
replied 6 months ago

>>Coming from the receiver when i look Message view in u-center.
Yeah, I’m not familiar of this as an error message coming from the receiver. Sure it’s not u-Center’s?
A screen-shot or a log would be helpful to understand this. If you use a Terminal application like RealTerm, what does that show? Use uCenter to record a .UBX of the interactions between it and the receiver.

>>Is it possible to configure the receiver to automatically hotstart every x time?
No, you’;d need to do that in your own application code, should probably try to root-cause the current issue.

How is this unit powered?

PK
replied 6 months ago

Exact message in GNTXT was this: Text indetifyer > Warning, Text > Unknown NMEA message and unit is powered by computer USB-port. RTCM feed can be found here rtk2go.com:2021 and mountpoint is “Piste”. I will log ubx messages tomorrow…

clive1
replied 6 months ago

Ok, that means you’re pushing in a NMEA message from caster as well as the RTCM3 messages.
You should filter that out of the stream. You might try changing the port settings of the interface you’re using to not accept NMEA as an input form.

PK
replied 6 months ago

Receiver is pushing out only RTCM messages. I only enabled NMEA to test GxTXT output but disabled it after test.

clive1
replied 6 months ago

Messages like $GPTXT,01,01,01,NMEA unknown msg*58 are indicative of NMEA sentence injection

PK
replied 6 months ago

I did some test with DJI Phantom RTK and rover. When Phantom receives correction data it will show how many gps, glonass, beidou,galileo sattelites basestation is observing. When the rover stop receiving or accepting RTCM messages from basestation then at the same time Phantom shows that basestation is observing 0 satellites. But Phantom still get fixed position…

PK answered 5 months ago
Now i got it working properly. Problem was time tags in RTCM message ; https://rtklibexplorer.wordpress.com/2017/02/01/a-fix-for-the-rtcm-time-tag-issue/
mlubich565
replied 2 weeks ago

Hello, how you resolve this problem (can you write details – add TADJ option or other settings for RTCM stream conversion)? I have same situation with STRSVR last version from Rtklibexplorer.

clive1
replied 2 weeks ago

Look for anything that would cause it to spit out NMEA Sentences. Perhaps look at the data stream output in a terminal application, then search for those in the source.

 

If time-stamp related, the receivers are going to issues if messages arrive out-of-order.

mlubich565
replied 2 weeks ago

Thanks of advices, trouble was time tags in RTCM message (decimal seconds after some time after power on). I solve this trouble use RAWX output, convert input stream to RTCM3 and use -TADJ=0.01 option in STRSVR.