Q&A forumCategory: Questionsseries-of-issues-with-rtcm3-base-rover-configuration
Hamilton asked 3 months ago

Hello my fellow developers,

I received two simpleRTK2B boards and started messing around with them, so far I did not achieve much and I’m having different issues. First let me explain my setup.

I have two simpleRTK2B boards, both with a Xbee module (That is on the same network and baudrate, tested it). I have configured the ZED-F9P using the u-center software, using the files I found on this topic: (Firmware v1.11).

The first issue is that when I apply the configuration I get the following message:
Firmware version

After that, the base-configured module can’t finish the survey-in and remains on Fix Mode: 3D (Issue number 2). So I have to put the location manually (which works for now, but will be an issue later), doing it makes the Fix Mode change from 3D to TIME. But I can’t see any RTCM3 messages on the message view. The last and by far strangest issue, is that if I change the UART2, it doesn’t change absolutely anything on the LEDs, on the other hand, if I change the Protocol in settings on UART1, the GPS > XBEE LED starts blinking

On the Rover board the XBEE > GPS LED blinks at same conditions of the GPS > XBEE on the other board, but Fix Mode remains 3D/DGNSS.

I’m using Ublox Antennas.

5 Answers
Kaupoi answered 3 months ago

Does our base antenna have a clear sky view so there is no trees or buildings near blocking the view?
What kind of antenna are you using?
Do you have a ground plane under antenna?

Hamilton replied 3 months ago

My antenna is a ANN-MB-00, clear sky view and no ground plane.

clive1 answered 3 months ago

You can use UBX-RXM-RTCM to see if messages are delivered.
Not sure why it wouldn’t be able to complete a Survey. If you plot a Deviation Map how does that look? How about the Sky View plot?
What does UBX-NAV-SVIN report in terms of survey progress?
The MSM7 RTCM3 messages should be transmittable even without a survey. 1005 depends on the survey, but one could also use 4072.0 and pretend to be a moving base in the mean time.

Hamilton replied 3 months ago

There is nothing on UBX-RXM-RTCM while trying to survey.
My Deviation Map looks fine, it starts all crazy, but after 30 seconds or so, every point on the deviation map is within the 2m radius. I lack the knowledge to fully undersand the Sky view plot(But after a quick read on the u-center User guide, it also looks fine). One thing I noticed is that after a while, it just stops. No more points are plotted on the map.
On the UBX-NAV-SVIN it says that the status is successfully finished and the mean position valid: Yes. So I guess I actually misinterpreted the problem, it is able to complete the survey. On the other hand the Fix Mode is still 3D and it is not sending RTCM3 messages.

Every messsage on RTCM3 is grey.

clive1 replied 3 months ago

You might want to enable UBX-NAV-PVT to see TIME mode, I don’t recall the NMEA messages having that status.
Check the RTCM3 settings via UBX-CFG-MSG, check which are enabled, and on which port(s)

Hamilton replied 3 months ago

Ok, sorry for the newbie questions, it is the first time I’m messing with ublox and RTK, so there is a lot of things that I don’t know.
I enabled the UBX-NAV-PVT and the base Fix Mode changed to TIME, I checked the RTCM3 settings via UBX-CFG-MSG and it is enabled on UART2 (Xbee)(1005, 1074, 1084, 1094, 1124, 1127 and 1230).
On the Hover, there is none enabled (as it should be as far as I understand), but still nothing on UBX-RMX-RTCM. sporadically tho, I see the fix mode changing from “3D/DGNSS” to “3D/DGNSS/FLOAT” and then back.

Hamilton answered 3 months ago

Ok, so far I solved the majority of my problems, I’m receiving the corrections on the Hover, and I got my base do finish the survey with 0.3 Accuracy. my hover on the other hand doesn’t seem to understand what to do with the correction cause it is acting just like a good normal GPS (30cm to 200cm accuracy).

skypuppy answered 3 months ago

Hamilton, have you set the base to “base” config and at the same time, set the rover to “rover” config, both at the current firmware version?

Hamilton replied 3 months ago

Yes, exactly, but my hover rarely changes from 3D/DGNSS/FLOAT TO 3D/DGNSS/FIXED

gpz1100r1150rtzzr400 answered 3 months ago

The problem you are facing is a little similar to what I experienced.

It’s ridiculous, but try RTK under “half-opened air” such as under the eaves of buildings.
If that improves the situation, there may be too much traffic on XBee. For example, does Rover’s F9P output something to UART2?

Hamilton replied 3 months ago

It is working fine now, but just to update, I was losing the correction packets on the Rover, so it was probably something with the GPS signal and Xbee signal.
To get a “3D/DGNSS/FIXED”, I have to be in a really open environment, but it works.