I have noticed during two flights yesterday that we received a warning stating GPS bad signal health while in the middle of a flight. This has never happened and am wondering if it is an upgrade to plane 3.9 issue? The person monitoring the GCS did not notice a drop in satellites from 18 or around that number.
Which type of GPS do you use? I have exactly the same problem.
But i also get in on the ground, maybe a minute after cold start.
I use the ublox m8n with 3.01 firmware. GPS, GLONASS and GALILEO active.
Hardware: Pixhawk 1 (orignal 3DR)
Same behaviour on 3.9.1 and 3.9.2 beta (3?), even switching back to Nuttx does not help.
26 Sats, HDOP 0,5.
Baudrate 115k, GPS type: ublox
To be able to arm the plane, i disabled GPS check in EKF2 & EKF3.
First observation was, the error appears with “DGPS” status. But i am not absolutely sure.
I am going to upload a log file.
The message you are seeing is only seen in newer versions of copter/plane. It’s basically because the GPS must maintain at least a 5 Hz update rate for the EKF to be happy. If the GPS goes below 5 Hz update rate they consider that unhealthy. You can look at the GPS.Delta field to get the time interval from the data flash log.
My M8N is set to 10Hz output rate, but i think it doesn’t reach the desired rate.
Do you mean GPA.Delta? I got values between 180 and 340, increasing with higher count of SATs visible.
So the ublox M8N seems to be too slow for GPS+GLONASS+GALILEO…
Official M8N documented rate for your configuration is 3Hz (not supported by arduxx).
GPS+GLONASS+SBAS is 5Hz
GPS+SBAS is 10Hz
Alright Marc, thought it is faster… I don’t understand why the M8Q ist faster than the M8N!
Now i have GPS+GALILEO+SBAS and no error message anymore. Going to check the GPA.Delta in the log file but it must be below 200msec now.
I have heard from many people that the “Bad GPS Signal Health” indicator only shows up when the GPS message rate drops below 5 Hz. In my case, I see this message when I lose all satellites.
In other words, if I cover the GPS with my hand, the GPS sats drops to zero, and I see “Bad GPS Signal Health” in MP. When I uncover the GPS and allow it to see the sky, the message goes away once the GPS reacquires satellites. Is this the expected behavior?