Compass error demonstration

sar104 · May 28, 2019

It would be nice to repeat this test with a different model, or a Mavic 2 with earlier firmware - I'm not sure whether this was the Mavic 2 behavior from the start or just a recent firmware change. I'd like to test the Mavic Pro but, firstly, it has two compasses which makes it harder (or at least more complicated) to spoof the magnetic field and, secondly, my Mavic Pro is running very old firmware. I could test my P4. Is anyone who has a Mavic Air interested in performing a somewhat tricky test that might result in needing a rapid switch to ATTI mode?

sar104 · May 30, 2019

Does anyone recall a Mavic 2 with a compass error? I've looked back over all the Mavic 2 events that I've examined from this forum, and I cannot find a single instance of a Mavic 2 exhibiting a compass error under any firmware version, so I suspect that this method was implemented right from the start. I wonder if that was also one of the reasons for going to a single compass. If that's the case then it is turning out to be a very robust solution to a relatively common problem.

RadioFlyerMan · May 30, 2019

sar104 said:
It would be nice to repeat this test with a different model, or a Mavic 2 with earlier firmware - I'm not sure whether this was the Mavic 2 behavior from the start or just a recent firmware change. I'd like to test the Mavic Pro but, firstly, it has two compasses which makes it harder (or at least more complicated) to spoof the magnetic field and, secondly, my Mavic Pro is running very old firmware. I could test my P4. Is anyone who has a Mavic Air interested in performing a somewhat tricky test that might result in needing a rapid switch to ATTI mode?

Regarding the switch to ATTI, not sure I can do that on my MPP, or at least I don’t know how.

sar104 · May 30, 2019

RadioFlyerMan said:
Regarding the switch to ATTI, not sure I can do that on my MPP, or at least I don’t know how.

You have to reprogram the mode switch - same process as for the M2:

Mavic 2 Atti mode

ToddCarey · May 30, 2019

@sar104 - Does it make any difference the order of the startup between the Remote Controller and the Aircraft. I had a period where I was constantly getting recalibrate compass errors, even though I know there was nothing around magnetic sources around (out on front lawn with no wiring or piping in the area). Since changing my routine to always start the RC first, then the AC, I have not gotten one recalibrate upon startup, even though my flights have been in some different areas. Does the order of startup actually make a difference?

old man mavic · May 30, 2019

i think that it is the correct way to do it RC on wait for it to link to the tablet or phone you are using then you get enter device start the drone and then a buzz and go fly that is the way i have always done it no compass error messages for me as well

sar104 · May 30, 2019

ToddCarey said:
@sar104 - Does it make any difference the order of the startup between the Remote Controller and the Aircraft. I had a period where I was constantly getting recalibrate compass errors, even though I know there was nothing around magnetic sources around (out on front lawn with no wiring or piping in the area). Since changing my routine to always start the RC first, then the AC, I have not gotten one recalibrate upon startup, even though my flights have been in some different areas. Does the order of startup actually make a difference?

I generally start the RC, the app and then the aircraft, for no particular reason. I haven't found that the sequence makes any discernible difference. Do you still get a move or calibrate message if you go back to the previous order of startup?

RadioFlyerMan · May 30, 2019

sar104 said:
You have to reprogram the mode switch - same process as for the M2:

Mavic 2 Atti mode

Does that mean I can reconfigure switch mode 1 SPORT 8 to TriPod 12 and get super-cinematic mode?

sar104 · May 30, 2019

RadioFlyerMan said:
Does that mean I can reconfigure switch mode 1 SPORT 8 to TriPod 12 and get super-cinematic mode?

Probably not. Tripod mode on the MPP is one of the intelligent flight modes, not a mode switch option, if I recall correctly.

RadioFlyerMan · May 30, 2019

sar104 said:
Probably not. Tripod mode on the MPP is one of the intelligent flight modes, not a mode switch option, if I recall correctly.

OK Thanks. I'm just ready to step out and try the ATTI mode, assuming I did it correctly. Never flown that way. I want to see what it's like.

sar104 · May 30, 2019

RadioFlyerMan said:
OK Thanks. I'm just ready to step out and try the ATTI mode, assuming I did it correctly. Never flown that way. I want to see what it's like.

It's very slippery.

AMann · May 30, 2019

Test it out at Magnet and Pie Islands north of Isle Royale in Lake Superior, pretty amazing how much magnetic interference one will encounter there:

Former Member · May 30, 2019

When I turn things on it is always the controller 1st then the aircraft and I wait till the controller connects to the aircraft. I do this especially in this order for the mavic air because the mavic air is sometimes finicky with its Wi-Fi connection and so is the spark.

After that I connect the device and the app should say ready to fly (or it might say "remove the gimbal clamp, moron.")

RadioFlyerMan · May 30, 2019

sar104 said:
It's very slippery.

Holy Cow!!! Look Ma, no brakes! Boy you really have to fly that thing. I have a 5 to 10 mph wind... I was laughing just to watch it drift. I did land it once in ATTI mode. Wow!

On the serious side, it's good experience in case you lose GPS, under a bridge, etc. It makes you appreciate what that thing is doing in GPS mode. I think I'll practice a little more, but then turn it off. I use Sport mode to get out of wind situations.

Thanks.

Former Member · May 30, 2019

sar104 said:
Does anyone recall a Mavic 2 with a compass error? I've looked back over all the Mavic 2 events that I've examined from this forum, and I cannot find a single instance of a Mavic 2 exhibiting a compass error under any firmware version, so I suspect that this method was implemented right from the start. I wonder if that was also one of the reasons for going to a single compass. If that's the case then it is turning out to be a very robust solution to a relatively common problem.

It's funny that you bring this up. I use the same LZ every day for multiple test flights on customers drones. In one day I could have for compas errors on mavic pros, and not a single 1 on a mavic 2. Same spot different drones, different resuls.

What could the reason be that the mavic 2 doesn't have compas errors like all the mavick pros do? A single more robust compass could That is not as susceptible to interference could be one of the reasons.

sar104 · May 30, 2019

Thunderdrones said:
It's funny that you bring this up. I use the same LZ every day for multiple test flights on customers drones. In one day I could have for compas errors on mavic pros, and not a single 1 on a mavic 2. Same spot different drones, different resuls.

What could the reason be that the mavic 2 doesn't have compas errors like all the mavick pros do? A single more robust compass could That is not as susceptible to interference could be one of the reasons.

The compass errors are reporting IMU / compass disagreement after takeoff. If you look at what is happening in the flight that I showed in post #60, instead of seeing the disagreement and throwing a compass error, the M2 FC simply gets rid of the disagreement by resetting the IMU yaw to agree with the new compass heading.

Former Member · May 30, 2019

sar104 said:
the M2 FC simply gets rid of the disagreement by resetting the IMU yaw to agree with the new compass heading.

and without sending the Mavic sailing into the nearest tree. I agree, quite an improvement!

Former Member · May 30, 2019

sar104 said:
The compass errors are reporting IMU / compass disagreement after takeoff. If you look at what is happening in the flight that I showed in post #60, instead of seeing the disagreement and throwing a compass error, the M2 FC simply gets rid of the disagreement by resetting the IMU yaw to agree with the new compass heading.

This reminds me of the old days in my dads Piper Colt (red headed step child of a Tripacer)

As part of the engine runup, we always aligned the DG to the compass reading. Do you think this is similar?

sar104 · May 30, 2019

Thunderdrones said:
This reminds me of the old days in my dads Piper Colt (red headed step child of a Tripacer)

As part of the engine runup, we always aligned the DG to the compass reading. Do you think this is similar?

It's a bit like if you took off and the compass and gyro suddenly disagreed, and then you re-aligned them.