Gaps in the RTCM stream from SimpleRTK2b base

Q&A forumGaps in the RTCM stream from SimpleRTK2b base
AndrewRL asked 8 months ago
AndrewRL replied 8 months ago

While debugging the Wifi NTRIP master with Nebkat we have discovered that there are temporary interruptions in the RTCM stream from the ZED-F9P to the UART of the XBee board, even after some hours of continuous and flawless operation.

With the new logging in the v0.5 update we can see this is happening once or twice per day. eg 3 times on the last 2 day – two times the break in streaming was about 20 seconds (long enough for rtk2go to drop the connection) but the other time was only for 10-15 seconds and the streaming resumed quick enough that the caster never timed out the connection.

I had assumed that once the base started streaming it spewed out RTCM with monotonous regularity every second but it seems that is not the case (or is there a problem with the UART on the XBee).

What factors might cause ZED-F9P in base mode to pause for a few seconds and then resume?

Can you log that? It does not seem to be sky related because even ehen I disconnected the antenna even though the MSM messages stopped and eventually the RTCM-1005 messages stopped the RTCM-1230 messages seemed to carry on for ever.

Ardusimple Staff replied 8 months ago

Hi Andrew,
That’s something for what we would need to open an investigation with u-blox.

1. As it might be related to your location, do you think it would be possible for you to record a logfile with debug messages enabled? This can be done via USB port, u-center Menu Bar : Receiver : Debug Messages. The file might get big, you can send to via wechat or another tool.
2. We would need to know at which time is this stop of output of RTCM corrections ocurring.
3. zed-f9p must be running FW 1.12.

With this we can open a ticket at u-blox with all info they need to analyze the case. Thanks again for your great help in these 2 investigations.

AndrewRL replied 8 months ago

I’ll look into logging. If we can compare with XBee logs we should be able to see whether ZED-F9P stops talking or Xbee stops listening.

How does the U-centre “Debug Messages” setting work. Is that only remembered in RAM (ie until power off) or does it persist?

I assume the latest FW is running as the board was new at the end of last year, but I will check that too.

Ardusimple Staff replied 8 months ago

Debug messages are only remembered until power off, unless you store if with ubx-cfg-cfg.
Note that ublox is still shipping today the modules with 1.11FW, if you did not update, you are running 1.11.

AndrewRL replied 8 months ago

I checked and I am on 1.11 as you said. I will change it to 1.12.

I tested logging but I got a mix of messages including NMEA.For the logfile you need do I need to turn off all output on USB except UBX?

Ardusimple Staff replied 8 months ago

It’s ok, you can mix NMEA and UBX.

AndrewRL replied 8 months ago

Update: I did the logging with v1.12 as you suggested but replaying with U-Centre I can see that UBX MON-IO says that ZED-F9P is sending data to UART2 all the while when XBee reports no data from the UART. So still some investigation to do.

1 Answers
AndrewRL answered 7 months ago

Logging the UART2 TTL output has confirmed that the ZED-F9P is continuing to send data all the while. Some issue in the Xbee is stopping it listening to it.
Please “close” this question as the logging has confirmed it is not a SimpleRTK2b issue.