DJI Mavic, Air and Mini Drones
Friendly, Helpful & Knowledgeable Community
Join Us Now

How to fly without using the compass

Jojoker65

New Member
Joined
Oct 14, 2019
Messages
2
Reactions
0
Age
30
Location
Chizé
Hello,

I would like to know if it is possible to fly the drone Mavic 2 Zoom without the compass? And if so, how to do that.

I leave for a mission in Antarctica and in these places, the magnetism is scrambled because of the magnetic poles and it does not allow to use devices with integrated compasses.

Thank you for your help.

Joris
 
Hello,

I would like to know if it is possible to fly the drone Mavic 2 Zoom without the compass? And if so, how to do that.

I leave for a mission in Antarctica and in these places, the magnetism is scrambled because of the magnetic poles and it does not allow to use devices with integrated compasses.

Thank you for your help.

Joris
The drone will just go into Atti mode and GPS won’t work. There will be no brakes and the drone will drift with the wind so you have to be careful about the amount of wind you fly in. It might be good to practice using Atti mode before you go. I imagine that would be a harsh place to try to learn how to fly in Atti mode
 
The drone will just go into Atti mode and GPS won’t work. There will be no brakes and the drone will drift with the wind so you have to be careful about the amount of wind you fly in. It might be good to practice using Atti mode before you go. I imagine that would be a harsh place to try to learn how to fly in Atti mode

Not sure I necessarily agree with either of those. Firstly, GPS will work just fine - coverage is global. The aircraft might drop into ATTI mode due to the high inclination on the magnetic field, but it may also just behave strangely.

Since the aircraft cannot operate properly without a reasonably accurate magnetic orientation, the only reliable way to operate at such latitudes is to force the aircraft into ATTI, preferably by mapping ATTI mode (flycState=1) onto one of the mode switch positions.
 
Not sure I necessarily agree with either of those. Firstly, GPS will work just fine - coverage is global. The aircraft might drop into ATTI mode due to the high inclination on the magnetic field, but it may also just behave strangely.

Since the aircraft cannot operate properly without a reasonably accurate magnetic orientation, the only reliable way to operate at such latitudes is to force the aircraft into ATTI, preferably by mapping ATTI mode (flycState=1) onto one of the mode switch positions.
What I meant is GPS positioning hold won’t work without a compass assuming it doesn’t work. Of course GPS Is available globally but Mavic 2 cant use it without a compass.
 
  • Like
Reactions: sar104
Not sure I necessarily agree with either of those. Firstly, GPS will work just fine - coverage is global. The aircraft might drop into ATTI mode due to the high inclination on the magnetic field, but it may also just behave strangely.

Since the aircraft cannot operate properly without a reasonably accurate magnetic orientation, the only reliable way to operate at such latitudes is to force the aircraft into ATTI, preferably by mapping ATTI mode (flycState=1) onto one of the mode switch positions.

Hello,

Thank you very much for this informations.

Just, what is the ATTI mode ?
 
Hello,

Thank you very much for this informations.

Just, what is the ATTI mode ?

ATTI mode is a flight mode in which the FC ignores positional data and simply holds the aircraft level (pitch and roll = 0°) and holds altitude, so it doesn't need reliable heading data from the compass. It will drift with the wind in the absence of active corrections by the pilot, and it won't stop if you center the sticks when it is moving - just continue to coast. Stopping requires active opposite thrust.

ATTI always was (and still is) a selectable flight mode on the Phantom range, but was omitted for some reason from the Mavics. However, you can remap it onto one of the flight mode switch positions (typically Sport or Tripod) by changing one of the internal parameters. The method is described in this thead:

Mavic 2 Atti mode
 
  • Like
Reactions: Gindra
Here is how you can reprogram your mode switch to turn on ATTI mode. You can use either the SPORT or TRIPOD position. I used the Tripod position which still gives me SPORT when I need to move quickly.

 
Here is how you can reprogram your mode switch to turn on ATTI mode. You can use either the SPORT or TRIPOD position. I used the Tripod position which still gives me SPORT when I need to move quickly.

Where would I find assistant 2 ver1.1.2. I checked DJI and Drone U.
DJI goes as low as ver 1.2.5. (not specific to Mavic)
 
ATTI mode will still adjust to hold yaw position, right?
Are we sure it doesn't rely on the compass for that?
 
ATTI mode will still adjust to hold yaw position, right?
Are we sure it doesn't rely on the compass for that?

It holds yaw primarily using the rate gyros, with the compass data used to correct for gyro drift. It will do that in P and ATTI modes.
 
It holds yaw primarily using the rate gyros, with the compass data used to correct for gyro drift. It will do that in P and ATTI modes.

And you wouldn't expect for the abnormal magnetism near the poles to have some effect on flight?
I would guess you would have to be standing right on top of the magnetic poles for it to actually prevent you from flying safely, but I would not be surprised to see at least a few instances of erratic yaw
 
And you wouldn't expect for the abnormal magnetism near the poles to have some effect on flight?
I would guess you would have to be standing right on top of the magnetic poles for it to actually prevent you from flying safely, but I would not be surprised to see at least a few instances of erratic yaw

In any of the P modes I'd expect the compass heading to be too inaccurate for navigation. It may be good enough to hold a yaw value, even if it doesn't have an accurate knowledge of what that yaw value is.
 
The drone will just go into Atti mode and GPS won’t work. There will be no brakes and the drone will drift with the wind so you have to be careful about the amount of wind you fly in. It might be good to practice using Atti mode before you go. I imagine that would be a harsh place to try to learn how to fly in Atti mode
Negative, Red Leader. Compass failure is not the same as no GPS lock. Without feedback from the compass, the FC hasn't a clue how to orient the bird. Don't believe me? Disconnect your compass and try to fly. OR...run a magnet past your compass to induce compass error and try to fly. Chances are the bird won't fly. Back in the old days, the bird would fly with compass error and was hard as hell to control.

D
 
Negative, Red Leader. Compass failure is not the same as no GPS lock. Without feedback from the compass, the FC hasn't a clue how to orient the bird. Don't believe me? Disconnect your compass and try to fly. OR...run a magnet past your compass to induce compass error and try to fly. Chances are the bird won't fly. Back in the old days, the bird would fly with compass error and was hard as hell to control.

D

You can disable compass through parameters. I tried it a few times and flight at low speeds was okay, but the faster you went the more the AC would yaw in a sudden motion... sometimes oscillating back and forth, too. Not one of the parameters I'd advise changing the default on ;)
 
Negative, Red Leader. Compass failure is not the same as no GPS lock. Without feedback from the compass, the FC hasn't a clue how to orient the bird. Don't believe me? Disconnect your compass and try to fly. OR...run a magnet past your compass to induce compass error and try to fly. Chances are the bird won't fly. Back in the old days, the bird would fly with compass error and was hard as hell to control.

D
Well if there’s compass failure the set action is to revert to Atti mode which only stabilizes the aircraft attitude

“The aircraft automatically changes to Attitude (ATTI) mode when the Vision Systems are unavailable or disabled and when the GPS signal is weak or the compass experiences interference.“
-Mavic 2 User Manual

I think where it can be difficult to control is when the aircraft is still using bad compass data for positioning.

Like @sar104 said
It holds yaw primarily using the rate gyros, with the compass data used to correct for gyro drift. It will do that in P and ATTI modes.
So you aren’t getting the benefit of the compass correcting for gyro drift which could make it a bit more difficult to control but I’m not positive I understand how that contradicts what I said.

Btw just losing GPS would first revert it to using just VPS, if conditions for it are met, and actually would put it into opti mode if it’s close enough to the ground. Tests I did recently show that at least the Mavic Pro Platinum can hold its positioning using VPS decently enough up to 120 feet AGL. M2 may have some software limitations on how high it will go using VPS. This might be adjustable.


Losing the compass, however, is why I said it would go to Atti mode and didn’t bring up Opti mode at all. Still needs compass for OPTI mode.
 
Last edited:
Well if there’s compass failure the set action is to revert to Atti mode which only stabilizes the aircraft attitude

“The aircraft automatically changes to Attitude (ATTI) mode when the Vision Systems are unavailable or disabled and when the GPS signal is weak or the compass experiences interference.“
-Mavic 2 User Manual

I think where it can be difficult to control is when the aircraft is still using bad compass data for positioning.

Like @sar104 said

So you aren’t getting the benefit of the compass correcting for gyro drift which could make it a bit more difficult to control but I’m not positive I understand how that contradicts what I said.

Btw just losing GPS would first revert it to using just VPS, if conditions for it are met, and actually would put it into opti mode if it’s close enough to the ground. Tests I did recently show that at least the Mavic Pro Platinum can hold its positioning using VPS decently enough up to 120 feet AGL. M2 may have some software limitations on how high it will go using VPS. This might be adjustable.


Losing the compass, however, is why I said it would go to Atti mode and didn’t bring up Opti mode at all. Still needs compass for OPTI mode.

You're confusing "compass error" with "compass failure." These are two different animals that will net completely different results. The OP makes a reference to flying "without the compass," which is different from flying with "compass interference."

Based on the fact that these new, modern birds with their fancy flight controllers won't even let you spin up the motors if there's too much compass error leads me to believe that they still rely heavily on compass data. Ergo, NO compass = no flight. Back in the day the P1's WOULD launch, even if they had compass error. But you better hang on to your hat because you were in for one VERY unpredictable flight.

I lost a compass during flight one time. It took me a half dozen attempts to land the bird. Even then, it was a rough landing.

And while VPS may compensate for SOME compass error indoors, at low altitudes or during landings, the VPS will do nothing for you @ 100' AGL.

D
 
You can disable compass through parameters.

I've been through the parameters of my P4P and Mavic Pro many times and don't recall seeing a parameter that allows one to DISABLE the compass. Are you sure about that???? I'll have to go back and check.

I tried it a few times and flight at low speeds was okay, but the faster you went the more the AC would yaw in a sudden motion... sometimes oscillating back and forth, too. Not one of the parameters I'd advise changing the default on ;)

Hmmmmm....You don't have a screen capture or know what the parameter is called, do you? I assume the word "Compass" appears in the parameter syntax, yes? I would really like to see this "Disable compass" parameter. Not to doubt your veracity, I just don't recall seeing it.

D
 
Lycus Tech Mavic Air 3 Case

DJI Drone Deals

New Threads

Forum statistics

Threads
130,599
Messages
1,554,247
Members
159,603
Latest member
refrigasketscanada