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which direction is the RADAR map point pointing towards?

tjcooper

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#1
I tried on 3 different cell phones today to understand where the red radar point is pointing. It was not pointing towards HOME or Rx unit. I always appears to be pointing 90 away from me when I have drone pointing at HOME or Rx unit which in this test are at same position. I thought it was supposed to point towards HOME or Rx when you initialize the navigation settings.

Are there some settings somewhere which the operator sets to indicate the direction of the red pointer?
tjcooper
 

AMRE2ME2

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#2
IMG_0179.PNG IMG_0178.PNG The white H in the center of the radar, is you or the 'controller'. As the UAV is flying away from you, the red arrow will be somewhere around the outer ring and pointing away from the center H. So now you know it is heading away from you.
See first pic.
When you are headed back towards yourself, the red arrow will be pointing towards the center and the white H. See second pic.
 

AMRE2ME2

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#3
As far as where the red arrow is around that circle, it's related to where the controller is pointing to in relation to where the UAV is. You can mess with it once youre in the air, it will make more sense then.
 

tjcooper

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#4
UPDATE: I found a thread under Mavic Pro HELP that talks about DJI failure of the compass/MPI signal when too close to cell phone and that causes the red triangle to point 90 deg away from correct direction. There is a statement that changing orientation by 180 degrees fixes problem. Didn't work for me.

CORRECTION: I am talking about the RADAR MAP not the radar blip signal shown above. I tried again last night using the long extension cable I bought off Amazon to make my Samsung Sensa be far away from the RC controller. Same problem. Also tried with Nexus 6 and my Samsung Tab3 Yoga tablet. All showed the same right angle misalignment.

I will post connection to other thread which talks about DJI admission that it is there problem and how many crashes have happened because of bad pointing when flying in MAP mode. Just need to find that thread again....read it just yesterday.
tjcooper

here is POST on Red Triangle error:
Serious bug in the Mavic's "Home Point Me" function - caused loss of drone!
see around page 6 for descriptions of errors found and that DJI acknowledges it is their problem
 

tjcooper

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#5
its been a year since I posted problem of RH pointer being off by 90 deg counter clockwise.
I just read all the responses on the above mentioned thread that DJI has admitted there is a problem with the RH not pointing correctly. No solution up to end of 2017.

I flew today with 3 cell phones with MP on new NLD software. Same problem. The red radar arrow is always 90 counter clockwise from where it should be. Has anyone heard of a "fix" for this problem? Please ennumerate if a solution exists. Also tried it with my googles on and had same 90 deg error.

NOTE: the NLD is at apk 4.2.22 The aircraft at 01.04.0200 now (it starts of 01.04.0300 but the patch puts it back one step. The new software is FANTASTIC. No more notifications that I am too close to airport (there are 5 of them that surround our flying field and my house. You have to "fix" the db on the aircraft and also on the DJI GO 4. Once done.....no more messages.
tjcooper
 

Meta4

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#6
its been a year since I posted problem of RH pointer being off by 90 deg counter clockwise.
I just read all the responses on the above mentioned thread that DJI has admitted there is a problem with the RH not pointing correctly. No solution up to end of 2017.

I flew today with 3 cell phones with MP on new NLD software. Same problem. The red radar arrow is always 90 counter clockwise from where it should be. Has anyone heard of a "fix" for this problem? Please ennumerate if a solution exists. Also tried it with my googles on and had same 90 deg error.
It's not a DJI issue and DJI would not have "admitted" anything about it.
It has nothing to do with the compass in your drone or the app/firmware etc.
It's entirely down to the compass in your phone/tablet and how well it is calibrated or how well it can be calibrated.

If it's an issue, load a compass app on your phone/tablet and see how well the compass is pointing toward north.
 

Kilrah

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#7
The 90° issue relates to how the device handles display rotation and whether it also "rotates" the compass data accordingly or not.

Some do and some don't which is the whole problem. The app can only assume one of either, if yours doesn't match too bad.
 

tjcooper

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#8
There is a thread on MavicPilots which has a person quote the staff at DJI that they know it is their problem. I will look around to see if I can find it. It was buried in a HP thread.

I always check the compass position of my 5 cell phones that I rotate through the MP controller. Their direction is accurate when they are "stand alone". One thread said they also saw the 90 deg ccw problem but that it was do to interference between the electronics in the cell phone and the electronics in the RC. That is why I have bought long extension microUSB cords and tested that possibility. Even with the long cards (roughly 3 feet) the 90 deg ccw still takes place. One of the thread contributors said that he had a conversation with DJI technical staff and they said that some cell phones try to give info to the DJI Go 4 app that indicates what the cell phone thinks is NORTH. The staff person said that sometimes the protocol of that info can lead to the DJI Go 4 getting confused, and that that could cause the rotation.

I have also tried rotating my RC with cell phone attached to see if that made a diference. No, same problem. It also happens with my goggles on. I did try to use a friend's iPhone which he used for his Phantom and when I did this the red arrow was correct. So this tells me that the problem is related to the specific cell phone model and OS. Regardless, the problem belongs to DJI because 4 of the 5 cell phones (Android) that I use are on their accepted cell phone list.

Since the "wrong direction" is always 90 deg ccw, you can "find your way home" by virtually rotating the arrow angle by 90 deg clockwise. But it is hard to remember to have to "fix" the display when you can barely see the drone and you need it to come home. Using the "fly a few seconds" and watch the distance indicator value also works.
tjcooper
 

Meta4

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#9
There is a thread on MavicPilots which has a person quote the staff at DJI that they know it is their problem.
That's not proof of anything.
Unfortunately DJI have many staff who are as unreliable for accurate information as many people that write things on forums.
I always check the compass position of my 5 cell phones that I rotate through the MP controller.
Compass position ?? Do you mean direction?
One thread said they also saw the 90 deg ccw problem but that it was do to interference between the electronics in the cell phone and the electronics in the RC
That sounds unlikely since the electronics in the controller has no detrimental effect on so many user's phones and tablets.

One of the thread contributors said that he had a conversation with DJI technical staff and they said that some cell phones try to give info to the DJI Go 4 app that indicates what the cell phone thinks is NORTH. The staff person said that sometimes the protocol of that info can lead to the DJI Go 4 getting confused, and that that could cause the rotation.
How much confusion has gone into that quote?
The simple fact is that the app will display the directional information that it is given by the phone or tablet.
If that information is accurate, so is the radar display.
So this tells me that the problem is related to the specific cell phone model and OS.
The OS is not a relevant factor.
Regardless, the problem belongs to DJI because 4 of the 5 cell phones (Android) that I use are on their accepted cell phone list.
Even a recommended phone will give bad directional data with an uncalibrated compass.
That ;s not something DJI can have any control over.
Since the "wrong direction" is always 90 deg ccw, you can "find your way home" by virtually rotating the arrow angle by 90 deg clockwise. But it is hard to remember to have to "fix" the display when you can barely see the drone and you need it to come home. Using the "fly a few seconds" and watch the distance indicator value also works.
I used to fly with a tablet who's compass could not be calibrated because the tablet had 8 powerful magnets in the case.
But even knowing the radar direction was not indicating correctly. it was still simple to fly home because home is always in the centre of the circle.
It's simply a matter of rotating the drone to face the centre and flying it straight ahead.
 

tjcooper

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#10
SOLUTION FOUND:
your observation that the fundamental problem lies with the cell phone is correct.

When I said that I test the cell phone compass each time I fly refers to the fact that I use Google Maps to determine that it knows where I am at and that is red pointer shows my current travel direction. That is all I tested because none of my Android phones have a "compass calibrate" like the drone does.

Anyway, when I downloaded from Google Play a compass apk and installed, it wants to do a compass calibration by doing the "figure 8" move. Once I did that, three of the four phones I tested now have the drone arrow pointing in the right direction. The Nexus 6p did not change....it was still at 90 deg ccw. So I loaded on it a gyro/compass/gps calibration package. That made the red arrow now come into true orientation.

So without loading a compass program onto your Android, you probably will not get good red arrow orientation. It turns out a factory reset of cell phone will blow off the calibration and you will have to do it again.

I then searched the DJI User Manual for Mavic Pro for the word "compass". There are 23 instances of it in the manual. Nowhere in the manual does it indicate that to get proper orientation of the red arrow you have to download a "compass program" (or gps calibrate program) in order for the software to work correctly. I will report this finding to DJI customer service and see if they can reproduce it. Would be very interesting to see if this carries over to the Mavic Pro 2.

Regardless, the ultimate fault is with DJI. They should have discovered that "most Android" phones will not work with the drone software for red arrow orientation. They should indicate in the same sections where they demand that you calibrate the drone compass, you need to download a 3rd party program and calibrate the cell phone compass/gps.
tjcooper
 

Meta4

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#11
That is all I tested because none of my Android phones have a "compass calibrate" like the drone does.
Look at this: LMGTFY
Nowhere in the manual does it indicate that to get proper orientation of the red arrow you have to download a "compass program" (or gps calibrate program) in order for the software to work correctly. I will report this finding to DJI customer service and see if they can reproduce it. Would be very interesting to see if this carries over to the Mavic Pro 2.
I seem to remember someone back in post #6 telling you to download a compass program and/or checking the calibration of the phone's compass.
I will report this finding to DJI customer service and see if they can reproduce it. Would be very interesting to see if this carries over to the Mavic Pro 2.
DJI won't care at all.
The issue was that your phone's compass was not displaying directional data properly.
The app gave it the correct data but the phone didn't know where north was.
It won't matter what model drone is used, the problem was in your phone.
Regardless, the ultimate fault is with DJI.
Your phone = your problem
 

tjcooper

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#12
Meta4,
much has happened since your response.

I contacted DJI about the red arrow problem. They say they have many customer reports of a problem but they are not able to reproduce it. So I made a video and sent it to them. But in the act of making the video I discovered many variations.

1) all 4 Android phones that "worked fine" after using the 3D compass apk yesterday, all now FAIL and give the 90deg CCW arrow today. No change to any software on the phones in that time frame.

2) The Nexus 6P which had failure yesterday had a "gyro/compass/gps calibration" and got the compass to work. But last night in a test it had the proper red arrow but the DJI goggles connected to it had the arrow at 90 deg ccw. This is the first time I have seen the goggles have anything different from RC with cell phone connected.

3) except for 2) above, all goggle connections have mirrored the OK or FAILURE of the red arrow on the cell phone hooked to RC.

4) Tested all 4 cell phones with Google MAPS to see if that caused the "beam width" and the arrow direction to match the map. (Thanks for your reference to the Google compass calibration). All phones except the Nexus 6p (which is made by Google) have always had the narrow blue beam work even when the drone has red arrow at 90 deg ccw failure work from day zero. The Nexus 6p had a broad beam and did not present an arrow on Google maps. In a 1/2 hour calibration test with Google MAPS, the Nexus 6p would sometimes show a narrow beam and an arrow, and a few seconds later as I was moving around would return to a broad beam and no arrow. Called Google about this, they indicated that all Android cell phones have very different compass/gyro sensors. If the unit has less than 35 microT units of magnetic strength, then the "real time calibration" in Google maps will go in and out of syncronization. That is exactly with the Nexus 6P was showing. Yet when I used the 3D compass map with its manual calibration, I could get the Nexus 6P to give steady but "low quality" calibration and give a reasonably accurate magnetc north. What this tells me is that the compass calibration inside the Android cell phone is "hit and miss" at best. You can just walk around your house and thet NORTH to move by 30 degrees in any 5 minute interval.

5) DJI customer support said that the compass values from the attached cell phone are not used by DJI Go 4. That is both confusing and somehow makes sense. Since the DJI has two compass units in it (and the goggles has a 3rd) why would they make use of a compass reading that can be defeated so easily? But everyone claims that the DRONE uses the compass readings which come in both IOS and Android variations.

6) while the DJI Go 4 apk said that I had "good" compass settings, I decided to recalibration the drone compass just in case that was the problem. When I finished, I retested all 4 cell phones and goggle, they all gave the same red arrow 90 deg ccw (so this was a change of the Nexus 6P now going back and having the goggle both agree). So drone compass was not a problem.
tjcooper
 
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Meta4

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#13
I can't follow all of your reply but theresa a lot of confusion in it.
You are confused about some things and you are also taking confused information from DJI.
5) DJI customer support said that the compass values from the attached cell phone are not used by DJI Go 4. That is both confusing and somehow makes sense. Since the DJI has two compass units in it (and the goggles has a 3rd) why would they make use of a compass reading that can be defeated so easily? But everyone claims that the DRONE uses the compass readings which come in both IOS and Android variations.
Everyone? Anyone that tells you that your drone uses compass information from your phone, doesn't know much about the drone.
Your drone has a very good compass that is all it needs for flight purposes.
It has no way to use compass data from your phone.
The only use for your phone's compass is to help the app display the radar or map to face the way you are facing.
If the phone's compass is giving bad data, the radar or map still works but its orientation will be wrong.
I told you about using a tablet with a bad compass.
The radar did not point the way I was pointing but home was always in the centre.
Despite this, I could always rotate the drone until the radar showed it was pointing towards the centre and fly home.

6) while the DJI Go 4 apk said that I had "good" compass settings, I decided to recalibration the drone compass just in case that was the problem. ... So drone compass was not a problem.
Of course the drone compass is not the problem.
The drone's compass is for flying. The phone's compass is just for orienting the map/radar display.
They are completely separate.
 

tjcooper

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#14
Meta4,
i do appreciate your comments. But they do not agree with what I see on my DJI Go 4 screen or what the DJI customer service has told me.

you said:
If the phone's compass is giving bad data, the radar or map still works but its orientation will be wrong.
I told you about using a tablet with a bad compass.
The radar did not point the way I was pointing but home was always in the centre.
Despite this, I could always rotate the drone until the radar showed it was pointing towards the centre and fly home.


but on my MAP screens (I do not use the RADAR screen) the direction of the drone arrow is wrong. If I rotated that arrow to point back to Home Position (HP) and flew forward, then I would fly off to China. The only safe way for me to return home is to rotate to a new direction and fly for a few seconds and look at "distance" metric. If that number gets larger, then I am flying away from home (which typically happens when I have the red map arrow pointing towards HP). I adjust another rotation of 90 degrees and fly a few more seconds, now the distance decreases. Now I am really flying towards HP. I perturb the rotation orientation until I get the biggest drop in the "distance" metric. When I do this, the red arrow is pointing to my right (ie. nose is pointing towards me).

And if that is not enough to rattle you cage, there is the test case when the outline arrow in the goggles points one direction and the red map arrow on the cell phone points 90 deg CCW to that one. Again, how to use the fastest drop of "distance" go finally get home. The DJI customer service has not seen the goggle have a different orientation from the map screen on the RC cell phone.

There are several other posts on DJI forum which has people telling about the red map arrow not pointing in the correct visually observable direction. Since I do not use the RADAR screen, I cannot tell what other MP users have seen.

I was wondering if I just had "bad software version". But I have tested 3 different versions on my 5 Android cell phones. At some point in time, they have all shown the red map arrow problem. And at other times they all point the right direction. I am now using NLD mod client to get rid of "too near of airport" notices which is using 01.04.0200. All the other cell phones are on latest rev and one step back.
 

Meta4

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#15
i do appreciate your comments. But they do not agree with what I see on my DJI Go 4 screen or what the DJI customer service has told me.
It's a mistake to assume that DJI customer service actually know what they are talking about.
Unfortunately they are not a reliable source for accurate information.
There are several other posts on DJI forum which has people telling about the red map arrow not pointing in the correct visually observable direction.
The DJI forum is an even worse information source.
I was wondering if I just had "bad software version". But I have tested 3 different versions on my 5 Android cell phones. At some point in time, they have all shown the red map arrow problem. And at other times they all point the right direction.
Not surprising.
The app just displays the information being fed into it.
If the app was a problem, everyone using it would have the same problems.
 
Likes: Aww@Mavic

tjcooper

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#16
Meta4,

I absolutely agree with your statement:

It's a mistake to assume that DJI customer service actually know what they are talking about.
Unfortunately they are not a reliable source for accurate information.


The person from DJI I talked with today absolutely negated what the previous DJI service person had said.

Today's person went through my problem and video and said no one has reported such a problem to DJI customer servce.
But the forums have several reported cases that match my problem: at least Android cases where the red map arrow is off by 90 deg ccw from real visible position of nose of drone. He also said that he has "full knowledge" that the compass on the cell phone DOES NOT go into DJI Go 4 application. The program only uses the two compasses on the drone. He also said something that I have a hard time believing. He said that the compass inside the goggles is not used to display position of your head with head gimbal, etc. He said just the gyro is used to steer the gimbles or the yaw when you choose that mode. We have torn the goggles down for market analysis (Amazon drone R&D). There is a compass and gyro in the goggles. Why would you not use it? Go figure.

I used the RADAR map today during tests in addition to red arrow on map. The arrow in the RADAR map was about 80 deg CLOCKWISE from true orientation. It was consistent but not just at a right angle to the true orientation. Go figure.

So today's DJI person said I had to re-flash the drone firmware. He says he has seen instances where the flash is incomplete and certain functions do not work properly. Hard to imagine that they do not use CRC before, during, and after flashing the Eprom in the drone. So I did that and wiped out the NLD client and had previously loaded. Absolutely no change in the results. All 4 cell phone exhibit the 90 deg ccw orientation of the red map arrow.

What was different today was that after each test I had the cell phone compass recalibrated (that had caused previously all 4 units to get to GOOD red arrow orientation). Today, no GOOD orientation. Everything still had 90 deg ccw misalignment. So I am now looking for what might cause the phones to give me GOOD orientation again. Or is it just a time random variable?

NEW PROBLEM: two of my cell phones (Note 4 and Nexus 6P) were both officially supported cell phones when I bought the Mavic Pro in Feb of last year. The DJI customer service person said he could not issue me a new case number today because those two phones are no longer on the "official approved mobile device" list. So now I need to hunt down a friend who has a phone on the list (btw, there is no clear place in DJI documentation where the official list stays current for more than 3 months).
I will borrow a Pixel 2 unit from work and see if that makes any changes. That is the only way they will let me "send my documentation to the code group in Japan".

Has anyone found an "official place" for current phones for DJI? I see one for Mavir Air, but not one for Mavic Pro.
tjcooper
 

Meta4

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#17
NEW PROBLEM: two of my cell phones (Note 4 and Nexus 6P) were both officially supported cell phones when I bought the Mavic Pro in Feb of last year. The DJI customer service person said he could not issue me a new case number today because those two phones are no longer on the "official approved mobile device" list. So now I need to hunt down a friend who has a phone on the list (btw, there is no clear place in DJI documentation where the official list stays current for more than 3 months).
I will borrow a Pixel 2 unit from work and see if that makes any changes. That is the only way they will let me "send my documentation to the code group in Japan".

Has anyone found an "official place" for current phones for DJI? I see one for Mavir Air, but not one for Mavic Pro.
DJI's official list is a bit of a joke.
They rarely update it to include new devices and there are many very good devices that they never test at all.
 

DanMan32

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#18
I have yet to come across a phone/tablet that I don't always have to do the figure 8 to calibrate it's compass when using said compass. Google Maps relies more on GPS than it does the compass, since most of the time you have enough lateral movement that it can calculate orientation based on GPS delta.

You can lock the map to heads up north rather than orienting map top based on which way you are facing, or rather what the device compass says you are facing.

So, if you are knowingly flying north and the drone icon doesn't point in the same direction as the itty bitty compass on the map, then there is a problem with the app.
However if you are facing north as well as the drone flying north, but the map shows you flying right, the device may be believing you're facing west and telling the app to display west up. Again that's assuming you don't have north up locked.

You can easily check if you have north up locked in the app map by turning around. If the map turns with you, the map is not locked to north up. If it stays in place, then north is locked up.
 

Meta4

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#19
I have yet to come across a phone/tablet that I don't always have to do the figure 8 to calibrate it's compass when using said compass. Google Maps relies more on GPS than it does the compass, since most of the time you have enough lateral movement that it can calculate orientation based on GPS delta.
GPS data is position data.
It can tell Google Maps where your tablet is.
It can tell what direction it might be moving but it can't tell which way it is facing.
That's what the compass is for.
 

DanMan32

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#20
PS, you don't even have to be connected to the RC to view and use the map in the Go app. You can prove the DJI is misinformed by making sure the map doesn't show a lock (tap on it if it does to release the lock), and turn around. You'll see the map move with you, and even the tiny compass will turn. orientation wrong? Do the figure 8 or spin the device in all 3 axes. It should then pretty much show correct heading you are facing.

Now if they misunderstood you to say the device was feeding the RC compass info, then they are probably correct. I can't see any reason the RC needs to know which way you are facing. Only the app needs that.

My WiFi only Tab E doesn't have a compass (magneto sensor). That was annoying. That and poor performance was why I ended getting the Tab S3.
 
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