For what it’s worth, I explored the possibility of auto-configuring the SimpleRTK2B+Heading boards from within ArduPilot today. I thought it might be as simple as adding a GPS_DRV_OPTIONS bit and then adding a couple of lines of code to change the UART config to match the config files from ArduSimple, but I quickly discovered that the auto configure routine does not seem to play well with the shared UART1 hardware setup on the Lite board. I do think it’s in the realm of possible, but I do not want to rewrite the mature and rather critical ArduPilot GPS driver. So unless the dev team wishes to tackle it, I’m afraid users will have to continue using the config files and uCenter.
Not working yet. Today I tried setting SERIAL1 and SERIAL2 to mode 5 and the other serials to mode -1 and no luck.
I have pored over the SimpleRTK2B+Heading docs and it seems that the UART which is used to pass the RTK messages from the big board to the small board is the same as the UART which is connected to the Pixhawk. As far as I can tell, the big board sends RTK messages (1207, etc.) on its UART2. See the “Xbee Socket” section of this document here https://www.ardusimple.com/simplertk2b-hookup-guide/ . Then, the small board receives those messages on its UART 1. See the “Bottom XBee Header” section of this document here simpleRTK2Blite hookup guide - ArduSimple However, the Pixhawk’s connection to the small board is also connected to this same UART 1. See the “Pixhawk connector” section of that same document. Hence the UART2 on the big board and the UART 1 on the small board and the Pixhawk Serial (Serial 2->UART 5 in my instance) are all connected together. I have some suspicion that this may be what makes this so finicky.
My testing time is limited next few days so progress will be slow… but I will keep you updated. I’m taking a brute-force approach of swapping out components (ardusimple boards, antennas, pixhawks, etc.) to identify which component is the source of the different behavior between my working mower and my not-working mower.
Again, I think it may be just a matter of swapping the two connections. See my post regarding serial mapping and GPS numbering above.
You are absolutely correct about this specific SimpleRTK arrangement’s “finickiness.” I’m all too familiar with it, and I do not use it for that reason. The design is somewhat clever, but I wish they’d put a set of jumpers on the larger board to make the XBee UART headers (physically) more configurable/flexible.
My configuration works just like you have explained, GPS2 is showing RTK fixed in u-center. When I connect my Ardupilot as well (with my GNSS heading module) on USB port, the rover, GPS2 after 1-2 minutes the signal precision decreases from RTK Fixed to 3D dgps.
Have this issue occured to you?
I am using SimpleRTK2B + Lite heading kit in a moving base configuration.