Enabling 10 Hz sampling rate in Ublox modules

Roi Yozevitch picture Roi Yozevitch · Oct 19, 2014 · Viewed 7.1k times · Source

I'm using ublox NEO-M8N-0-01 GNSS module. This module supports up to 5Hz GPS+GLONASS and 10 Hz GPS only.

However, when I try to change the sampling rate (via UBX-CFG-RATE in the messages view) I can only increase it to 5 Hz (Measurement period = 200ms). Any value below 200ms is impossible (changes the box to pink).

It happens even if I only produce NMEA message GxGGA.

The way I made it only GPS was via UBX-CFG-GNSS

Has anyone encountered this issue?

Thanks in advance

Roi Yozevitch

Answer

Andrew picture Andrew · Feb 4, 2015

You don't say how you are setting the rate however going by your description I'm assuming you are using the ublox u-center software.

There is a simple explanation for this issue and a simple solution: Their software has a bug in (or wasn't updated to match the final specification of the part).

The solution is to not use u-center, it's the PC software that's complaining not the receiver. The receiver itself doesn't care what the spec sheet says, it will try it's best to run at whatever rate you request.

Sending commands directly I've managed to get a fairly reliable 10Hz GPS+Glonass. There is the occasional missing point but most of the time it keeps up.

Running GPS only you can get faster than 10Hz. If you play with the settings and restrict it to 8 channels 18-19Hz is fairly reliable. Unfortunately 20Hz is pushing it too far, you end up getting positions at 10Hz.

Obviously when running at these update rates make sure that your baud rate is high enough to cope with the requested messages and rate.