Labroides Posted at 11-21 13:55
But the orientation display at the bottom of the screen does rely on the GPS of both devices.
The Fly app has introduced that "feature" which was not present in DJI Go 4.
In DJI Go 4, whether the viewing device had/didn't have a GPS made no difference.

"The Fly app pops up the red icon if there's no GPS available on the phone or tablet, but does the orientation display still function?
How do all the wifi iPad users manage, do they still get a functioning orientation display or not?
Or if using Android, do you still get a functioning orientation display when you turn GPS off?"

If I am understanding the question, post #53 should answer that. I have seen those indications.

But I will verify that for Android later tonight if I can remember ;-)
Followup later this night. I tested the display and it was the same as in the post 53 image. The screen is very dark but you can just see the crossed out indicator:

JJB* Posted at 11-21 01:49
Airline pilot do not re-calibrate their magnetic compass during long distance flights, its confusing to read this even if it is within "" later in your text.
They simply adjust the East or West variation on a dial to the position where they are flying to get a correct True N reference point for all the other 359 headings....

"Think about this....when calibrating DJI drone users can start on any heading the calibration, just make a 360 turn (flat+nose down).  SW measures the normal expected variation in magn fields though the magnetometer and if its done in a free of magn interference area  calibration is succesfull. Minor deviations through a full circle are averaged. Done."

Agreed. This is a vital point in the discussion, and one that many people simply do not understand. There is no point in the compass dance where you point the aircraft in a guaranteed heading, so the whole process cannot reasonably be called a 'calibration', because when calibrating any variable you would have to tell the device under calibration that the current variable corresponds to a known value. At no point in the compass dance do you do anything that indicates where either magnetic or true north is located.

At the risk of starting another fight, and hurting even more butts, I will also suggest that local magnetic variation is a complete red-herring also. Given the very short distances over which we fly our drones, and also that we do not plot a course for them in the same sense as full sized aircraft, local magnetic variations do not matter at all. Even in the hypothetical situation where we might plot two waypoints, possibly several miles apart, the compass is only taking a relatively small and minor part in the navigational exercise between the two points. The aircraft knows where it is and where it should be, from that it can calculate a heading. It then uses the compass to turn the aircraft to that heading, and off it goes. Several times per second during the flight, the aircraft performs the same calculation, so that if the original heading was not quite correct, or wind has pushed the aircraft off course, a new heading is generated for the aircraft. as a result, tiny course corrections are being made all the time, so in fact you could have a quite large local magnetic deviation and it would make almost negligible difference to the aircraft's navigation.

Geebax Posted at 11-21 15:43
"Think about this....when calibrating DJI drone users can start on any heading the calibration, just make a 360 turn (flat+nose down).  SW measures the normal expected variation in magn fields though the magnetometer and if its done in a free of magn interference area  calibration is succesfull. Minor deviations through a full circle are averaged. Done."

Agreed. This is a vital point in the discussion, and one that many people simply do not understand. There is no point in the compass dance where you point the aircraft in a guaranteed heading, so the whole process cannot reasonably be called a 'calibration', because when calibrating any variable you would have to tell the device under calibration that the current variable corresponds to a known value. At no point in the compass dance do you do anything that indicates where either magnetic or true north is located.

Also the fact that you can get a brand new DJI drone from China and fly it properly anywhere in the world without recalibrating the compass, kind of shoots that heresy down rather effectively.

GaryDoug Posted at 11-21 15:40
"The Fly app pops up the red icon if there's no GPS available on the phone or tablet, but does the orientation display still function?
How do all the wifi iPad users manage, do they still get a functioning orientation display or not?
Or if using Android, do you still get a functioning orientation display when you turn GPS off?"

If DJI's wording in those screenshots is telling the truth, it would indicate some dopey programming on their part.
Wifi iPad users never had a problem with the orientation indicator in DJI Go 4.
I've used Android tablets with GPS on and off (in Go 4) and the orientation indicator works perfectly with either.

Why DJI would require mobile device GPS for the orientation indicator in DJI Fly is a mystery as it really makes no difference for almost all flights.

This is not a compass issue.

I just got back from flying.  I turned off Location Services for the whole phone.  Location Services is what Apple calls geolocation \ GPS.  The the red icon appeared in the the positioning indicator at the bottom of the screen indicating no phone GPS.  The heading indicator arrow also disappears.  I even broke down and tried an iPad to eliminate my phone from the equation.  

I am perplexed at the logic of removing the arrow as the drones heading comes from the drone and not GPS or the phone's compass.  Maybe it was just not ascetically fluid.  It still might be useful to have even if there is a GPS error.

Starting the drone on the ground and stepping away about 25 feet helps to reduce the positioning error but it is still not properly aligned with the RC.  I also tried rotating  the drone both vertically and horizontally and RC at different distances and angles.  I took a couple of short flights out about 1,500ft and rotated the drone 360° to see if it would reduce the error in flight.  I tried a bunch of other random things to no avail.  It remained slightly off until I did a Compass Calibration.  Something in the Compass Calibration process appears to also be executing another process because it is properly aligned afterwards.  
My compass heading arrow has never been inaccurate not have I been prompted to calibrate after setup.

JJB* Posted at 11-21 01:49
Airline pilot do not re-calibrate their magnetic compass during long distance flights, its confusing to read this even if it is within "" later in your text.
They simply adjust the East or West variation on a dial to the position where they are flying to get a correct True N reference point for all the other 359 headings....

You did not read what I wrote. I said that they do not calibrate the compass but adjust the heading to support their current location.

JJB* Posted at 11-21 08:10
"Your drone records a home point location at startup and uses GPS to find its way back to that."

adding "and use drone compass to fly the calculated heading..."

Correct But it must have the Deviation to true north "Calibrated / Adjusted" to do this.

bjr981s Posted at 11-21 18:42
Correct But it must have the Deviation to true north "Calibrated / Adjusted" to do this.

It does not care about the deviation, read what I wrote in post #85.

Labroides Posted at 11-21 16:03
If DJI's wording in those screenshots is telling the truth, it would indicate some dopey programming on their part.
Wifi iPad users never had a problem with the orientation indicator in DJI Go 4.
I've used Android tablets with GPS on and off (in Go 4) and the orientation indicator works perfectly with either.

First: I have no idea who created those images. I got them from another member's post here months ago. But I have seen all of the images in problematic situations and they are accurate.

Second: See post #84. Same result tonight as the 3rd image in post #53.

Third: I would consider an app that does not take into account the controller/device location in determining the orientation and relative bearing of the drone to be defective and vulnerable. If you move to another location, the display would no longer have relavence to your position but to an earlier one (HP). In some cases, like the ones where I am "boating", that would be troublesome and useless. I have used the orientation display many times while moving around. I could always check it to see where the drone was relative to me and that was very helpful, not at all if it had shown that info only relative to the HP. So in my opinion, this is a bug fix with the Fly app. Otherwise, it is just a duplication of the map view. Should it be an option? Sure.

KlooGee Posted at 11-21 03:19
Having said all of the above, I may expose a bit of my ignorance here....  I don't see why the drone would care at all about true north vs. magnetic north.  In "real" aviation, planes are flying long distances (hundreds or thousands of miles/kilometers) and are navigating via the compass heading.  So knowing true vs. magnetic north is vitally important to be able to navigate over those long distances.

However, with a drone, it is not navigating via a specific heading.  It is not likely to travel more than a handful of miles from its launch point and it really isn't navigating to a specific heading.  All it really needs to care about is a consistent heading and being able to compare that to the accelerometer's data about when it is turning.  It could label SW as 0 degrees if it wanted to.  It is just the deviation away from that heading that is important, not the actual correct heading degree.

Yes,

The issue is 2 fold.

The first, is that the drone was built in China and cannot know the declination of the location it will be flown. So ideally you need to calibrate the drone compass so it can determine declination at the users location. My Mini 2 requested a calibration before it would allow me to fly after activation. This is also an issue if you were to bring a drone from the USA to Australia to fly. The accuracy of the compasses in drones has improved over the years. I provide online support for another drone manufacturer. Their recommendation on drones from 5+ years ago was to calibrate the drone compass if you travelled more than 100 klm form you last calibration point.

The second, is local magnetic anomalies. Magnetic anomalies will offset the compass's magnetic north. Requiring calibration for the anomaly.

Now none of this is worth a bean if you don't use waypoints or don't use RTH. For normal operations it doesn't to care which direction is magnetic or true north as it operates via the accelerometer and Compass, it measures the change from a current relative position.

Now the issue that arise from not having an accurate declination adjustment is for Waypoint and RTH.

Again this would not be worth a bean if drones continually second by second did a calculation as to GPS end point coordinates and current bearing. This is a drift calculation. It is used by Pilots of aircraft that have a significant cross wind. Or a ship captain that has a serious wind or cross current.

Now the issue that is coupled with this is the actual waypoint or RTH position itself.

A waypoint or RTH position is a ring of specified diameter. The HDOP accuracy of a GPS is about 2 metres. So you need a ring that is greater than 2 metres but just not too much more, or waypoint or RTH will be only as accurate as the outer marker of the circle. Once it hits this outer marker it will attempt to get as close a GPS position to home point as it can. Later DJI drones do an Image reconciliation for RTH once it gets within this range circle. Obviously  it cant to that for a waypoint as it does not have that image to compare.

Now as the drone does not do continual calculations for bearing adjustment as far as I can tell, and experienced, this leads to a RTH error. If the bearing is significantly off, it will miss this outer marker and continue on its way till the batteries deplete.

You can see this occur when people report that the RTH came close to where the user was located but then just keeps going.

99% of the time you will be OK. But that 1% is a lost drone.
        
If you take off from a location (even if your did calculate the correct deviation from your home location)  
with a significant magnetic anomaly, like from the roof of your car or from a structure with underground  iron work (REO) the calculation for a correct bearing on RTH can even flip from north to south.

Anyhow I hope this helps in understanding the Issue as I see it. As I said, I support a different drone manufacturer and they are quite clear about compass calibrations for RTH drones. Even DJI goes to the point of forcing a regular calibration request on some models.

It's is best to follow manufacturer recommendations.

Everyone is free to do what ever they want but I would recommend wearing a mask   

JohnLietzke Posted at 11-21 17:11
This is not a compass issue.

I just got back from flying.  I turned off Location Services for the whole phone.  Location Services is what Apple calls geolocation \ GPS.  The the red icon appeared in the the positioning indicator at the bottom of the screen indicating no phone GPS.  The heading indicator arrow also disappears.  I even broke down and tried an iPad to eliminate my phone from the equation.  

"I am perplexed at the logic of removing the arrow as the drones heading comes from the drone and not GPS or the phone's compass.  Maybe it was just not ascetically fluid.  It still might be useful to have even if there is a GPS error."

You still have the map view. The map view uses North and the HP as the references. Without those references on the orientation display, there is no useful information as the controller/device is now the reference and without compass and/or GPS that is erronous.

There is one bug I have noticed in the Fly app. If the device has no compass, there is no change in the display and no warning about that. So we get bad information. I have that problem with one of my tablets (no compass capability) and the orientation display (not map) still looks ok but is very much in error.

That is odd that the compass indicator does not change to reflect no compass of the hardware lacks support. Let me run it in Xcode tomorrow and see that happens when the compass is not supported. I still have a first generation iPad in a cabinet. It should throw a service not available type warning. DJI probably never envisioned some this technology because the compass was implemented starting with the iPad Air about two years later. Are you using a first generation iPad or iPad mini?

I really want a Smart Controller but with app update delay and the non working compass indicator I have held off.  Today I replied to a smart controller forum about the compass indicator not working period and asked what the symbol is.  I was thinking maybe in the Smart Controller operating system had the compass disabled in latest firmware update.

I also was able to downloaded a copy of the DJI Go 4 to look at how the compass indicator is populated. I have a feeling it is the as the DJI Fly app.

I only have Android devices. And neither tablets are approved so I can't really complain.

GaryDoug Posted at 11-21 13:10
Actually I did document that just before posting my comment above. These images are the result of walking to the left of the stationary drone (first image) and then walking to the right of it (second image). Drone remained fixed, pointed generally west. I kept controller and device facing west as well. So this shows that the position of the controller's phone/tablet device (not the HP) partially determines the placement of the drone on the indicator. i.e. GPS and compass are both used for this display.
[view_image][view_image]

Yes, as i said how it works.  if you had yawed your RC away from your West, than this was not seen on the AOI. (only seen when you loose contact ofcourse...)

In the GoApp i used before, on Android device with GPS and compass, exactly the same as in the FlyApp. Only there you could see the arrow behind you if the drone was behind ythe RC.

cheers
JJB

So I did some test flying and here’s my results.
When using the map I yaw to line up the arrow with the blue line and fly forward, it comes right back to the home point on the map (I do check that the home point has been set before flying).
I then did a hyper lapse using waypoints and it flew the route I plotted.
I checked the position arc on the bottom of the display, using iPad as screen, and when I can see it the arc can be red, so I’m not sure what that means. I don’t use that at all so it’s not a big deal to me. Maybe I should pay more attention to it so if so please let me know.
I fly visual and reference the screen for recording and will also toggle the map if it’s looking like a dot and I’m not sure of the orientation.

Sorting through the responses and my own experience, not nearly as much as all of you have, I have not nor will I calibrate the compass unless I have a flying issue.
From what I have been reading a calibration in the wrong area, near metal, can actually cause more issues than it will resolve.

This thread was an interesting read and I thank you all for your thoughts and opinions.

Lisa3 Posted at 11-22 05:47
So I did some test flying and here’s my results.
When using the map I yaw to line up the arrow with the blue line and fly forward, it comes right back to the home point on the map (I do check that the home point has been set before flying).
I then did a hyper lapse using waypoints and it flew the route I plotted.

Everything well done.
The blue line you mentioned is the direct shortest way between the MA2 and homepoint set at start. This will be the same route that will be taken for RTH.
The other line you mentioned, is the route the the MA2 has already flown or planed to fly.
If you have a look on the map even if you fly manually, you can see the line / track you did fly + the direct line to the HP.
The direct line will be updated dynamically according to the drones position in flight. The other 2 are static on the map until you land and or restart for another flight.

Lisa3 Posted at 11-22 05:47
So I did some test flying and here’s my results.
When using the map I yaw to line up the arrow with the blue line and fly forward, it comes right back to the home point on the map (I do check that the home point has been set before flying).
I then did a hyper lapse using waypoints and it flew the route I plotted.

just uploaded a video about all this > https://forum.dji.com/forum.php? ... D556%26typeid%3D556

cheers
JJB

JJB* Posted at 11-22 07:04
just uploaded a video about all this > https://forum.dji.com/forum.php?mod=viewthread&tid=229714&extra=page%3D1%26filter%3Dtypeid%26typeid%3D556%26typeid%3D556

cheers

Well done. Now it should be more clear to some people, that the position indicator is a mix of phones GPS / Compass and MA2 GPS  / Compass.

1. GPS on MA2 to calculate the relative angle between HP and current location.
2. Compass on MA2 to calculate it's heading.
3. Compass on phone to calculate the viewing angle / heading of the pilot/RC (within the 180 degree front view)
4 . GPS on MA2 and Phone to calculate the current location on the map and the relative angle between MA2 and Pilot/RC.
5. GPS on MA2 and Phone to calculate the relative angle between MA2 and Pilot ( like 1. angle between MA2 and HP) + Compass on Phone to calculate by adding or subtracting the heading angle of the pilot / RC from or to the relative angle between MA2 and Pilot/RC to show the correct relative angle between MA2 and Pilot/RC in relation to where the Pilot/RC are currently pointing / heading to, if the pilot/RC  is turning around his vertical axis.

This is why both or either compass have to be calibrated from time to time, but not as often as discussed obove or written in any manual.

MySky Posted at 11-22 08:41
Well done. Now it should be more clear to some people, that the position indicator is a mix of phones GPS / Compass and MA2 GPS  / Compass.

1. GPS on MA2 to calculate the relative angle between HP and current location.

Thanks for breaking it down and disguising between the Home Point line on the Map and the position angle of the pilot to drone.  I think there has been a lot of confusion for some people on the difference.

The blue line on the map shows the shortest distance to the Home Point which would be used on the RTH.  This is fixed to the Home Point so the drone to return to that location in the event it looses signal and not the pilots locations which might not be a good place to land.

It does appear from the decompiled code of the DJI GO 4 app that the process is the same as in the DJI Fly app for calculating the position angle of the drone from the pilot.  The decompiler has a lot of artifacts, i.e. weird characters.  But the premise appears to be the same.

GaryDoug Posted at 11-21 21:39
I only have Android devices. And neither tablets are approved so I can't really complain.

Android and unrecommended devices may add another layer of problems to the equation.  But I did just try a few things this morning and discovered that for the old iPad it will try to get a heading direction using GPS comparison of the last two coordinates.  

Here is an article with an example of the equation and explanation.  https://towardsdatascience.com/calculating-the-bearing-between-two-geospatial-coordinates-66203f57e4b4
I tried using this method a cople of years ago for an Apple Watch app before the compass hardware was added.  It work poorly for detecting direction changes in realtime but was fairly accurate if a course directions was maintianed for signifcant duration.  I ended up abandoning the feature due to inaccuracy.

Since the Map works and that is GPS maybe the positioning and the direction of the drone are available, try moving forward and backward 30ft  to see if the positioning is updated.  Doing this will not be very accurate in realtime and I would not rely on it.

Lisa3 Posted at 11-22 05:47
So I did some test flying and here’s my results.
When using the map I yaw to line up the arrow with the blue line and fly forward, it comes right back to the home point on the map (I do check that the home point has been set before flying).
I then did a hyper lapse using waypoints and it flew the route I plotted.

I end up using the position arc when flying in areas where the signal is weak due to dense WiFi and it is hard to see the drone due to the contrast of the background for short periods of time.  The alignment of the RC with the drone helps improve signal quality.  Even thought the drone is often less than 1,000ft away and still visible the hills several miles way that have trees in certain areas and are not golden make it hard to see.  I typically fly via Camera and Map for this short period of time but tend to keep my RC pointed in the last direction of the drone, the position arc helps me keep controller aligned with the drone so the signal remains strong.  

Visual flight is also my preferred flight method, as it should be based on regulations, but I do find it hard to be able to accurately see the drone at all times due to the background contrast.  Also looking down at the camera while flying laterally to my position I have lots spacial relationship to where the drone is and use the position arc to reorient myself visually.  

I feel like the position arc's usefulness is very environment dependent.  Some flight I do not need to use it at all and others I am constantly checking it.  When it was smoky here I had to use it quite frequently as the drone was hard to locate due to the grayish background after I looked down at the camera.  But using the position arc I was able to look in that direction and find it.  Yesterday it was so clear I could see the Mavic Air 2 at over 2,000ft.  

JohnLietzke Posted at 11-22 09:05
Thanks for breaking it down and disguising between the Home Point line on the Map and the position angle of the pilot to drone.  I think there has been a lot of confusion for some people on the difference.

The blue line on the map shows the shortest distance to the Home Point which would be used on the RTH.  This is fixed to the Home Point so the drone to return to that location in the event it looses signal and not the pilots locations which might not be a good place to land.

Hi John

It is the 'reddish colour' line wich is always a straight line Drone<>HP.
Blue lines are lines where drone has flown already.

cheers
JJB

JJB* Posted at 11-22 12:21
Hi John

It is the 'reddish colour' line wich is always a straight line DroneHP.

You are correct.  The blue thick line is the recorded flight path and the red is the shortest distance to the Home Point.  

It irritates me that the blue flight path line does not populate the previously flown portions of route during the flight and only begins the line at the point where the map is first opened.  This should not be hard to fix as the flight data is being transmitted to the phone and saved.

MySky Posted at 11-22 08:41
Well done. Now it should be more clear to some people, that the position indicator is a mix of phones GPS / Compass and MA2 GPS  / Compass.

1. GPS on MA2 to calculate the relative angle between HP and current location.

Hi,

IMO not completely correct.

1. GPS on MA2 to calculate the relative angle between HP and current location.
GPS drone and HP GPS coordinates stored in the drone > FlyApp draw a line in the map view

2. Compass on MA2 to calculate it's heading.
Drone compass heading is shown as the arrow direction in the map view and arrow direction on the AOI

3. Compass on phone to calculate the viewing angle / heading of the pilot/RC (within the 180 degree front view)
Mob device compass is used to show the drone relative position to HP position on the 180 front view.

4 . GPS on MA2 and Phone to calculate the current location on the map and the relative angle between MA2 and Pilot/RC.
No, current location on the map view is only data from drone GPS + compass data for arrow pointing.
(without a phone compass/gps this will still work in map view)

5. GPS on MA2 and Phone to calculate the relative angle between MA2 and Pilot ( like 1. angle between MA2 and HP) + Compass on Phone to calculate by adding or subtracting the heading angle of the pilot / RC from or to the relative angle between MA2 and Pilot/RC to show the correct relative angle between MA2 and Pilot/RC in relation to where the Pilot/RC are currently pointing / heading to, if the pilot/RC  is turning around his vertical axis.
No, relative angle is as in pt.1. Line uses only GPS data drone and stored HP data in the drone.
If you walk away from your start point = HP, than red line does not change.

cheers
JJB

JohnLietzke Posted at 11-22 12:41
You are correct.  The blue thick line is the recorded flight path and the red is the shortest distance to the Home Point.  

It irritates me that the blue flight path line does not populate the previously flown portions of route during the flight and only begins the line at the point where the map is first opened.  This should not be hard to fix as the flight data is being transmitted to the phone and saved.

i never use the blue lines, for me they can dissapear for good  ;-)

many users, many ideas, many different ways to operate and use drones. Great free world it is !

cheers
JJB

John
I owe you an apology, I mistakenly said I followed the blue line to the home point when in fact it is red.
I believe I planted the blue line seed.
I did do another flight to verify my mistake and the direct line to home is in fact red.
Sorry about that.

JJB
I closed the corner map after switching back to camera view and the position arc came back as you noted.

Sorry and Thank You.

JJB* Posted at 11-22 12:44
Hi,

IMO not completely correct.

You misunderstood 4. and 5.

4. You need GPS from the phone and MA2 to show both locations on the map  and both for the relative angle calculation between MA2  and Pilot as needed in 5 (not HP). -> I was correct.

5. For sure there is no line drawn on the map between MA2 and Pilot location, like it is done between MA2 and HP.  GPS on the MA2  and phone + compass on phone are used to calculate the correct relative angle between MA2 and Pilot, even if pilot walks away from the HP or turns around his own vertical axis, as shown in the location information in the middle bottom of the Fly app, to help the pilot to find the right direction, where he has to look at, to find the MA2 again if he lost it. Means a virtual line of sight. -> i was right.

The relativ angel between MA2 and HP is only calculated by GPS data on the MA2 and will even work on failure of the RC. Line on the map between those points.

The relative angle between MA2 and pilot is calculated on the phone by GPS data from MA2 and Phone + compass information from phone to indicate the correct realative position of  the MA2  in relation to the pilots direction of view, independent from the HP and Mapview.

You see, 2 different calculations for two different relative angles.
Maybe you mixed  them up while reading.
Please read again. Or have a look at you own video.

MySky Posted at 11-22 08:41
Well done. Now it should be more clear to some people, that the position indicator is a mix of phones GPS / Compass and MA2 GPS  / Compass.

1. GPS on MA2 to calculate the relative angle between HP and current location.

This is why both or either compass have to be calibrated from time to  time, but not as often as discussed obove or written in any manual.
What's the reason you say that either compass needs to be recalibrated from time to time?
What changes and needs correcting?

Akirasho Posted at 11-19 05:49
The is the advise I follow... mostly...  before first flight or when in a "new" geo location.

https://youtu.be/CppskNOHWJI

Thanks for the video. I will begin to change my habits immediately!

R_Packard Posted at 11-22 16:04
Thanks for the video. I will begin to change my habits immediately!

You would be making a mistake.
The guy that made the video is just spreading misinformation.
He doesn't understand what he's talking about.

Lisa3 Posted at 11-22 14:27
John
I owe you an apology, I mistakenly said I followed the blue line to the home point when in fact it is red.
I believe I planted the blue line seed.

No worries.  It happens.  

JJB* Posted at 11-22 01:06
Yes, as i said how it works.  if you had yawed your RC away from your West, than this was not seen on the AOI. (only seen when you loose contact ofcourse...)

In the GoApp i used before, on Android device with GPS and compass, exactly the same as in the FlyApp. Only there you could see the arrow behind you if the drone was behind ythe RC.

I'm sorry for the late reply...but I do not understand your second line "(if you had yawed..."). It was probably lost in translation ;-) Can you rephrase it please?

Labroides Posted at 11-22 16:02
This is why both or either compass have to be calibrated from time to  time, but not as often as discussed obove or written in any manual.
What's the reason you say that either compass needs to be recalibrated from time to time?
What changes and needs correcting?

Because if either of the devices has a distorted compass due to whatever reason.
I didn't have to calibrate my MA2 since i got it in May, but i have to do it aprox.
every 2 to 3 weeks on my mobile phone, because it shows the wrong direction to  north.
On my old quad and hexa copter (not DJI) i had to do it once or twice within 2 years.
So it can happen that both needed to be calibrated at the same or not.

MySky Posted at 11-22 22:58
Because if either of the devices has a distorted compass due to whatever reason.
I didn't have to calibrate my MA2 since i got it in May, but i have to do it aprox.
every 2 to 3 weeks on my mobile phone, because it shows the wrong direction to  north.

I'm gotr over 4 years of heavy use with a P4 pro and Huawei tablet and neither have ever had anything calibrated and are working perfectly.

MySky Posted at 11-22 15:21
You misunderstood 4. and 5.

4. You need GPS from the phone and MA2 to show both locations on the map  and both for the relative angle calculation between MA2  and Pilot as needed in 5 (not HP). -> I was correct.

Hi,

Mayby i misunderstood, so what do you mean with "relative angle" in #4 ?

I read your "4 . GPS on MA2 and Phone to calculate the current location on the map and the relative angle between MA2 and Pilot/RC."as only for the map view, so relative angle is the line arrow to HP. If you meant the relative angle = position on the AOI scale ; yes  than you need compass data from the mobile device as well.

cheers
JJB

GaryDoug Posted at 11-22 20:49
I'm sorry for the late reply...but I do not understand your second line "(if you had yawed..."). It was probably lost in translation ;-) Can you rephrase it please?

Hi Gary,

ofcourse, what i mean is to turn your RC to the left and right, see my video last part.

cheers
JJB

Labroides Posted at 11-22 23:53
I'm gotr over 4 years of heavy use with a P4 pro and Huawei tablet and neither have ever had anything calibrated and are working perfectly.

Lucky you,  i hope this will be  the same with my MA2.
With the recurrent issue on my mobile i am ok to recalibrate it

JJB* Posted at 11-23 00:50
Hi,

Mayby i misunderstood, so what do you mean with "relative angle" in #4 ?

If you meant the relative angle = position on the AOI scale ; yes  than you need compass data from the mobile device as well.

Exactly

bjr981s Posted at 11-21 19:24
Yes,

The issue is 2 fold.

I think we both still fundamentally disagree with what is happening during the compass calibration process.  I still agree with Geebax and Labroides' technical descriptions.

Cheers, and yes, wear a mask!

Geebax Posted at 11-21 15:43
"Think about this....when calibrating DJI drone users can start on any heading the calibration, just make a 360 turn (flat+nose down).  SW measures the normal expected variation in magn fields though the magnetometer and if its done in a free of magn interference area  calibration is succesfull. Minor deviations through a full circle are averaged. Done."

Agreed. This is a vital point in the discussion, and one that many people simply do not understand. There is no point in the compass dance where you point the aircraft in a guaranteed heading, so the whole process cannot reasonably be called a 'calibration', because when calibrating any variable you would have to tell the device under calibration that the current variable corresponds to a known value. At no point in the compass dance do you do anything that indicates where either magnetic or true north is located.

"At the risk of starting another fight, and hurting even more butts, I will also suggest that local magnetic variation is a complete red-herring also."

I'm glad to see someone else with a similar thought.  I expressed basically the same thought in post #66.  Cheers!