M2 Doesn't Output Full Data Over Serial

So this is interesting. I am using an M2 as a secondary GNSS (blended w/Here3+) on Ardupilot.

ReachView is showing 30-ish+ satellites in view but the M2 isn’t sending out more than 16 on average, usually lower. That’s on either/both serial outputs.

(Ardupilot/CubeOrange) Output 1: Serial, UART, ERB, 115200
(U-Blox U-Center) Output 2: Serial, USB-to-PC, NMEA, 115200

Is there a reason that the serial output is different than what’s shown in ReachView?


Mission Planner/Ardupilot

U-Blox U-Center

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Hi @csweeting,

Welcome to our community!

As I know, Mission Planner shows only the number of satellites involved in the solution calculation. It’s the number transmitted in the NMEA GGA message. And it’s indeed lower than the number of all visible satellites because the satellites with low SNR or elevation are filtered out.

GNSS receivers need at least 4 clear satellite signals to calculate a solution. So, 13 satellites should work well.