Please select Into the mobile phone version | Continue to access the computer ver.
Mavic 2 Pro - Compass Redundancy ?
2145 26 2018-8-31
Uploading and Loding Picture ...(0/1)
o(^-^)o
DMX_MT
Captain

Malta
Offline

Just a fast question guys -

Is it True that the Mavic 2 Pro / Mavic 2 Zoom have only - 1 Compass and 2 IMUs ?

Open for comments !

I am debating this with a Friend of Mine, as we both have 2 Compasses and 2 IMUs in our Mavic Pros First Generation / Platinum Editions.

Would appreciate if some Admin come in this Post and Confirm for us.


2018-8-31
Use props
gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
Offline

Its got 1 compass and 2 IMUs.

Might not be a show stopper - the drone is so small any interference on 1 most likely affects the other as well.

There's also the fact that 2 isnt exactly redundancy - its got a spare if one stops working completely (rare) BUT if you have 2 compasses, both reporting data the flight controller has no way knowing which one is actually right.  For that you need 3 (or more) and elective voting.
2018-8-31
Use props
DJI Paladin
Super Moderator
Flight distance : 318 ft

Offline

Yes, you are correct. Mavic 2 is designed to have dual IMU and single compass. Let us know if you have other concern, we are happy to help.
2018-8-31
Use props
DMX_MT
Captain

Malta
Offline

gnirtS Posted at 2018-8-31 03:52
Its got 1 compass and 2 IMUs.

Might not be a show stopper - the drone is so small any interference on 1 most likely affects the other as well.

Thanks for such an Indepth Review gnirtS !

2018-8-31
Use props
DMX_MT
Captain

Malta
Offline

DJI Paladin Posted at 2018-8-31 05:16
Yes, you are correct. Mavic 2 is designed to have dual IMU and single compass. Let us know if you have other concern, we are happy to help.

Thank you once again for confirming it DJI Paladin.

2018-8-31
Use props
DJI Paladin
Super Moderator
Flight distance : 318 ft

Offline

DMX_MT Posted at 2018-8-31 06:30
Thank you once again for confirming it DJI Paladin.

You're always welcome!
2018-8-31
Use props
Elmo
lvl.2
Flight distance : 10279 ft
Offline

I'm trying to calibrate the imu and followed the instructions on the screen carefully but I am totally unable to complete the calibration. I cannot figure out what I am doing wrong. Is there a video that explains it well as anything I have found so far just isn't working for me.

Thanks.
2018-8-31
Use props
DMX_MT
Captain

Malta
Offline

Elmo Posted at 2018-8-31 12:33
I'm trying to calibrate the imu and followed the instructions on the screen carefully but I am totally unable to complete the calibration. I cannot figure out what I am doing wrong. Is there a video that explains it well as anything I have found so far just isn't working for me.

Thanks.

Hi Elmo, I am sorry but I have the Mavic 1 Pro Platinum.

Tutorial for Calibrating the IMU

Check if this helps Mate - Remember to remove the Propellers.

2018-9-1
Use props
gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
Offline

Elmo Posted at 2018-8-31 12:33
I'm trying to calibrate the imu and followed the instructions on the screen carefully but I am totally unable to complete the calibration. I cannot figure out what I am doing wrong. Is there a video that explains it well as anything I have found so far just isn't working for me.

Thanks.

There's a bug in Go4 showing the wrong procedure.
The one picture is incorrect.
On the 3rd blue dot where it shows the drone flat and upright it SHOULD show it on its back end ponting vertically upwards.
If you do that, it'll work.
Its a wrong picture.
2018-9-1
Use props
marcus.mkeeler
lvl.2
  • >>>
Offline

"There's also the fact that 2 isnt exactly redundancy - its got a spare if one stops working completely (rare) "

Hmm, that IS exactly what redundancy is.
2018-9-1
Use props
gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
Offline

marcus.mkeeler Posted at 2018-9-1 05:28
"There's also the fact that 2 isnt exactly redundancy - its got a spare if one stops working completely (rare) "

Hmm, that IS exactly what redundancy is.

Not really.  Stop working *completely* is one failure mode.

Incorrect data due to a fault is another.  And if one compass is giving garbage data with only 2 compasses you have no idea which one is correct.

Which is why you usually have 3 redundant systems for anything involving data feeds.
2018-9-1
Use props
Elmo
lvl.2
Flight distance : 10279 ft
Ireland
Offline

gnirtS Posted at 2018-9-1 04:08
There's a bug in Go4 showing the wrong procedure.
The one picture is incorrect.
On the 3rd blue dot where it shows the drone flat and upright it SHOULD show it on its back end ponting vertically upwards.

Thanks. I got it calibrated at last. Now I just have to learn how to fly it
2018-9-1
Use props
Elmo
lvl.2
Flight distance : 10279 ft
Ireland
Offline

DMX_MT Posted at 2018-9-1 03:35
Hi Elmo, I am sorry but I have the Mavic 1 Pro Platinum.

Tutorial for Calibrating the IMU

Thanks DMX
2018-9-1
Use props
DMX_MT
Captain

Malta
Offline



Glad you solved it Buddy ! Take it slow when Flying and keep in VLOS.

2018-9-2
Use props
\\\\LEEKER
lvl.2
  • >>>
Canada
Offline

gnirtS Posted at 2018-9-1 08:59
Not really.  Stop working *completely* is one failure mode.

Incorrect data due to a fault is another.  And if one compass is giving garbage data with only 2 compasses you have no idea which one is correct.

Not trying to start a fight or anything, but there are different types of failure. Total failure is one thing but at the same time you have a failure where a unit seems to function but provides poor or unreliable data/functionality.
Specifically in DJI's case, and more specifically in the case of the compass, this is actually relatively easy to detect. The system hardware/firmware conducts 'sanity' checks on the sub systems all the time and identifies what it detects to be erroneous behaviour. (have you noticed that DJI firmware now tells you to do a compass cal as opposed to it being a matter of standard procedure?).

Put simply, the system is checking the compass values all the time and if it sees that, for example, it's not getting a clear peak for magnetic North, it's flags a problem. Remember how back 'in the day' we could look at the compass values in the Naza systems?  It's the same, the system can identify between a fresh sharp set of values and a set drifting toward being a problem.  

In anycase, the compass has always been the item to catch non-flyers out. I know guys who refuse to calibrate until they are told to do so by the bird itself and who have nearly always flight characteristics indicative of a building compass error.

A bad IMU is a lost cause, bad compass? Disable GPS.  
2018-9-2
Use props
gnirtS
Captain
Flight distance : 2993497 ft
United Kingdom
Offline

Unfortunately theres no way to "flag" a problem if it doesnt recognise.  There are plenty incidents where it doesnt flag an error and reports incorrect.
On something bigger where you can separate the compasses physically and electrically by a lot more i'd understand having dual compasses.
But putting 2 so close together probably solves nothing.

If the IMU is toast then not a lot you can do.  You cant "fly" it like an aircraft and if it doesnt know how to control its roll and pitch its going down and rapidly.
2018-9-2
Use props
Crayo
lvl.2
Flight distance : 15833 ft
Finland
Offline

Mavic 2 has only one compass module while Mavic 1 Pro has two compass modules for redundancy.

Also, it looks like M2 has similar IMU/Compass hardware to Mavic Air. Maybe this change is to cut production costs?

My experience is that both Mavic Air and Mavic 2 are experiencing more issues with compass interference than the previous generation Mavic 1 Pro.

2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

Crayo Posted at 2018-10-25 02:31
Mavic 2 has only one compass module while Mavic 1 Pro has two compass modules for redundancy.

Also, it looks like M2 has similar IMU/Compass hardware to Mavic Air. Maybe this change is to cut production costs?

I think you will undoubtedly find that there have been very few if any reported crashes with Mavic 2, reported here or anywhere else, so whatever they have done with M2 compass it’s working well.
On the other hand Mavic Pro was dogged with compass problems while flying going into Atti mode and crashing, there is no doubt that whatever system they are now using in M2 has far fewer problems than we have had with Mavic Pro .
2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

\\\\LEEKER Posted at 2018-9-2 10:30
Not trying to start a fight or anything, but there are different types of failure. Total failure is one thing but at the same time you have a failure where a unit seems to function but provides poor or unreliable data/functionality.
Specifically in DJI's case, and more specifically in the case of the compass, this is actually relatively easy to detect. The system hardware/firmware conducts 'sanity' checks on the sub systems all the time and identifies what it detects to be erroneous behaviour. (have you noticed that DJI firmware now tells you to do a compass cal as opposed to it being a matter of standard procedure?).

Calibration gives the compass the information it needs to determine which magnetic influences are part of the Mavic and what is the earth's normal magnetic field.
The compass doesn't lose calibration and doesn't ever need re-calibration unless you add or remove equipment to/from the Mavic.

And yes I know your craft will from time to time ask for calibration, particularly when travelling some distance. There are also ways in your app to check the values of your compass and if it has attracted magnetic interference from where it is being launched from, in this case it is always better to move location and restart your craft.
2018-10-25
Use props
Aardvark
Captain
Flight distance : 384432 ft
  • >>>
United Kingdom
Offline

hallmark007 Posted at 2018-10-25 02:40
I think you will undoubtedly find that there have been very few if any reported crashes with Mavic 2, reported here or anywhere else, so whatever they have done with M2 compass it’s working well.
On the other hand Mavic Pro was dogged with compass problems while flying going into Atti mode and crashing, there is no doubt that whatever system they are now using in M2 has far fewer problems than we have had with Mavic Pro .

"On the other hand Mavic Pro was dogged with compass problems while flying going into Atti mode and crashing"

There can't have been too many of these, perhaps in the initial stages (as seems with the Mavic Air), I don't think I've ever had any compass irregularities on my Mavic Pro or P4 both of which have dual compass'. Redundancy in equipment is never a bad thing; whether it serves much practical purpose might be open to discussion  (if single compass faulty then I assume no take off, or at worst ATTI mode).
2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

Aardvark Posted at 2018-10-25 03:14
"On the other hand Mavic Pro was dogged with compass problems while flying going into Atti mode and crashing"

There can't have been too many of these, perhaps in the initial stages (as seems with the Mavic Air), I don't think I've ever had any compass irregularities on my Mavic Pro or P4 both of which have dual compass'. Redundancy in equipment is never a bad thing; whether it serves much practical purpose might be open to discussion  (if single compass faulty then I assume no take off, or at worst ATTI mode).

Although I don’t see to many being reported around here lately, when Mavic Pro was first released and for a long time after I have seen many problems and crashes as a result of compass interference, aircraft being lost because of fly away, crashed in Atti mode etc.
I have yet to see one case of fly away with M2 and likewise not many going into Atti mode because of conflict with magnetic interference.
While redundancy is great, it must also serve its purpose, I woul think it’s better to have one reliable compass which could be better shielded from interference than two not preforming. And I except what your saying regards P4 and Mavic Pro , I have owned both since they were released and still fly them without any issues, much I believe because of simple preflight checks and envoirment’s I normally fly in .
They became so regular, it forced this person to create a list
https://airtable.com/shrlFvMeiBLTE7coL/tblSSnOdmUp7uMR3x
2018-10-25
Use props
HedgeTrimmer
Captain
United States
Offline

As pointed out, having two compasses can help when one compass entirely fails.  Especially when in flight.

Argument was made that when one compass conflicts with other compass, it would not help since you need three (aka majority vote).
However, that ignores compass conflicts in which output of one compass can be determined to be incorrect by further analysis of onboard system.  Realizing each compass has three magnetic field sensors (XYZ axis), and output of each should correspond with known drone movement via IMU.   Along with checking each of three sensors (XYZ) of two compasses for invalid values.

The second compass, when positioned away from first compass (as with Mavic Pro P), can help in situations where there is localized magnetic field interference (aka Rebar).   For example, one compass is flagged with magnetic interference (Red bar), while other compass is flagged with minor magnetic interference (Yellow bar) or none (Green bar).  Drone can switch from using compass with excessive interference (Red bar).


2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

I believe this thread is about M2 only having 1 compass, try staying on track.
2018-10-25
Use props
HedgeTrimmer
Captain
United States
Offline

"when  Mavic Pro was first released and for a long time after I have seen many  problems and crashes as a result of compass interference, aircraft being  lost because of fly away, crashed in Atti mode etc."
"And I except what your saying regards P4 and Mavic Pro ,"

People are also discussing cons/pros of Mavic 2 having only one compass vs. Mavic Pro having two compasses.  
2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

Again dragging everything down to your own level, you mentioned nothing about M2 so we’re totally off topic, but that’s what you continue to do on most threads around, most of what you wrote is completely wrong, but the thread is yours now, just stop trolling.
2018-10-25
Use props
HedgeTrimmer
Captain
United States
Offline

hallmark007 Posted at 2018-10-25 12:05
Again dragging everything down to your own level, you mentioned nothing about M2 so we’re totally off topic, but that’s what you continue to do on most threads around, most of what you wrote is completely wrong, but the thread is yours now, just stop trolling.

See you are back to your usual tactics.  Accuse others of doing what you yourself are doing.  Your snot nosed childish remark of of "try staying on track" is utterly Hypocritical.

As for your remark about dragging down, it is you who has ZERO credibility.  A known Liar, a known Fraud, a known Troll, a known Braggart, and known Jackleg.
2018-10-25
Use props
hallmark007
Captain
Flight distance : 4199094 ft
  • >>>
Ireland
Online

HedgeTrimmer Posted at 2018-10-25 12:35
See you are back to your usual tactics.  Accuse others of doing what you yourself are doing.  Your snot nosed childish remark of of "try staying on track" is utterly Hypocritical.

As for your remark about dragging down, it is you who has ZERO credibility.  A known Liar, a known Fraud, a known Troll, a known Braggart, and known Jackleg.

I think you were run out of one thread yesterday with good reason , you do nothing around here except thrashing threads, every time I comment on a thread , your in behind me with nothing but ridiculous comments ,
I think on another thread yesterday someone referred to you as an idiot, I fully agree, now stop trolling me , take a run and jump.
Your best friend wingspeed is gone just a pity your not gone with him.
Now for the last time go away and bother someone else.
2018-10-25
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules