NEO-M8P-2 RTCM3 via UART

GPS/GNSS Development Boards
1

I am using 2 Sparkfun NEO-M8P-2 breakouts (PN 15005). Each one is connected via USB to its own PC running ublox ucenter. The modules are connected via a wire between their UART pins.

The base module has completed its SVIN and has a TIME fix. I am broadcasting RTCM3 messages 1005, 1077, 1087, and 1230. I can see in UBX->MON->IO that it is transmitting via UART1. In Ports, I have UART1 set to output RTCM3, input NONE and baud 9600.

The rover is operating in 3D mode. In ports I have UART1 set to output NONE, input RTCM3, and baud 9600. I can see in UBX->MON->IO that it is receiving data. However, in UBX->MON->MSGPP, all data is being received as unknown bytes, with none being received as RTCM3 messages.

I followed the setup in the ucenter users guide. Is there a known reason why the bytes are not being received as RTCM3 data? I have a 3rd NEO-M8P-2 and tried that as the base station (then as rover) and I get the same issue.

Does anyone have an idea what is the issue or a good way to troubleshoot this?

2

Hi Builder_Dane,

Based on your description, it sounds like you have everything set up correctly so I’m not quite sure what is causing the issue here. Can you take a few photos of your connections between the two GPS modules and attach them to your reply? Please do your best to make sure they are clear and well-lit. Similarly, if you could take screenshots of your configuration settings (where possible) and the monitor printouts showing the transmitted correction data and the unknown bytes the rover is receiving? A .txt file of that data would also work if you can create one.

As a sanity check, are you able to connect one of the NEO-M8P’s to an NTRIP client to receive RTCM data from a static correction source? That would help figure out where things are breaking down.