Mavic Mini GPS Levels?

[dccraven]

During a recent Maven waypoint flight I received an abrupt alert telling me the mission had stopped. Immediately following that announcement I received another alert stating something about low GPS signal strength (I couldn't remember the exact words). I pressed RTH and the drone returned to me with no problems.
Upon examining the data and comparing it to several successful completions of this same waypoint mission, I found that the event occurred when the GPS Level fell to 2. The remainder of the flight had a GPS Level of 4 or 5. When I compared the number of GPS satellites during this event it indicated that we had 18 or 19 satellites; the same as we had with a GPS Level of 5.
What does a GPS Level 2 indicate? What causes this?
Thanks in advance for you help!
Doug

 

[slup]

The so called GPS level is a value that say how reliable the flight controller think's the GPS position is ... 5 is the best. Below 3 the FC usually falls back to "Opti mode" to help out with the horizontal positional hold ... but only if the sensors on the AC belly is enough close to a ground with a good pattern to lock on to, & if it's not too dark. If all means of horizontal position input is lost the FC eventually reverts to ATTI mode (usually take some time) which means no horizontal hold, no breaking when releasing the sticks & no possibility for the AC to know where it is or where the HP is so no RTH is possible anymore.

Most probably you fell to a 2 for a short time (all automated flight modes will be aborted then...) ... but was back to at least a 3 when you pushed RTH.

Impossible to say why this happened without seeing the flight log.

 

[dccraven]

The so called GPS level is a value that say how reliable the flight controller think's the GPS position is ... 5 is the best. Below 3 the FC usually falls back to "Opti mode" to help out with the horizontal positional hold ... but only if the sensors on the AC belly is enough close to a ground with a good pattern to lock on to, & if it's not too dark. If all means of horizontal position input is lost the FC eventually reverts to ATTI mode (usually take some time) which means no horizontal hold, no breaking when releasing the sticks & no possibility for the AC to know where it is or where the HP is so no RTH is possible anymore.

Most probably you fell to a 2 for a short time (all automated flight modes will be aborted then...) ... but was back to at least a 3 when you pushed RTH.

Impossible to say why this happened without seeing the flight log.

Thanks for the info! From what I read of the data, it only stayed in the GPS Level 2 condition for 1 second. 0.3 seconds into this condition the drone changed from Joystick to PGPS flight mode and stayed there until I pushed the RTH button. I did not push the button for RTH until about 18 seconds after the flight mode change so, as you suggested, the drone was back in a GPS Level 5 state and easily came home. Attached is the txt file from the flight. Let me know if you see anything that might explain the sudden drop in GPS Level. I repeated the flight today and it went perfectly. Thanks again for your help.

 

[Meta4]

Attached is the txt file from the flight. Let me know if you see anything that might explain the sudden drop in GPS Level.

The data shows no reason for the drone to drop GPS health for one second.
It was 300 feet op with nothing to block the satellite signals.
Satellite numberswere 19 before, during and after.
Whatever it was, it was a brief, temporary glitch.

 

[slup]

Yep ... nothing than a temporary glitch, if this behavior isn't repeating on regular basis I don't think this is something you should worry about.

Nothing was obscuring the sky at all where you flew up there on 292ft, the short drop to GPS level 2 from 5 occurred at the red cross.



The drop to level 2 was very short (but enough to abort your automated flight) and lasted from 145,702sec to 146,902sec.

Below the green graph show the drop ... together with the sat count & height. Blue background is the automated flight mode & the white is ordinary p-GPS mode.

 

[BudWalker]

During a recent Maven waypoint flight I received an abrupt alert telling me the mission had stopped. Immediately following that announcement I received another alert stating something about low GPS signal strength (I couldn't remember the exact words). I pressed RTH and the drone returned to me with no problems.
Upon examining the data and comparing it to several successful completions of this same waypoint mission, I found that the event occurred when the GPS Level fell to 2. The remainder of the flight had a GPS Level of 4 or 5. When I compared the number of GPS satellites during this event it indicated that we had 18 or 19 satellites; the same as we had with a GPS Level of 5.
What does a GPS Level 2 indicate? What causes this?
Thanks in advance for you help!
Doug

A small detail perhaps. GpsLevel isn't the confidence in the GPS position - it's the confidence in the position computed by fusing IMU, magnetometer and GPS data. Certainly gpsLevel can drop because of GPS problems. But, it's almost always the case that a drop occurs due to magnetometer or IMU data inconsistencies.
@slup