Hi.

So, today, I launched the drone from my outside porch, just for a few still shot I needed.
As always, I have my screen recording on, so I have the "whole" flight there.
I waited for the amount of locked GPS sattelites to allow home point detection, and I took the drone up. Sure enough, I immediately got the "home point updated" message.
But then, as the drone was moving around, I noticed a strange behaviour I've never widnessed before: The home point seems to be "attached" to the drone, as was moving along with it.
I have no idea how that happened. I didn't even think this was possible, but there it is: That behaviour is starting at 1:09, and continues throughout the flight.
Also, in 1:14, the green dot in the center of the compass, becomes cyan. I'm guessing this has to do with the reception of the GPS to the RC itself (why do I need to guess. A callout or on screen message would be much better).

DJI - will appreciate your input here.

Thank you.

Is it that the home point and drone are moving? Or could it be that the controller thinks it i.e. the controller, is moving i.e. it has a poor GPS lock? Did you actually move the drone horizontally?

Sean-bumble-bee Posted at 12-15 09:04
Is it that the home point and drone are moving? Or could it be that the controller thinks it i.e. the controller, is moving i.e. it has a poor GPS lock? Did you actually move the drone horizontally?

I was standing in a rather tight space, and was absolutely stationary. The drone was flying high above me, and the Home Point somehow got attached to it instead of to my RC. So strange.

Amit Dunsky Posted at 12-15 11:07
I was standing in a rather tight space, and was absolutely stationary. The drone was flying high above me, and the Home Point somehow got stuck to it instead of my RC. So strange.

You misunderstand my question, the controller must get information from somewhere to determine its position, if that information is lacking might the reported position of the controller wander?

Did you command the drone to move horizontally?

Notice that your controller is center of Attitude indicator. This is much more sensitive to very minor movements of the controller as it shows on the indicator, i.e., small movements of the controller appear as very large movements. Even more so when the controller and drone are close together. It's no big deal, try switching thr drone to center.

Sean-bumble-bee Posted at 12-15 11:15
You misunderstand my question, the controller must get information from somewhere to determine its position, if that information is lacking might the reported position of the controller wander?

Did you command the drone to move horizontally?

I think I do understand you question. You're implying the movement shown is actually the RC moving in relation to the home point, and not vice versa. Is that right?

Yes, I did made the drone move ever so slightly to the sides. But all in all, it was a "go straight  up, take pictures, come back down" kind of flight, while I myself wasn't moving more than meter. Practically stationary.

I've been flying this drone almost a hundred times. I'm not new to flying it. But still yet - I've never seen the home point moving in the compass view.

Mobilehomer Posted at 12-15 11:16
Notice that your controller is center of Attitude indicator. This is much more sensitive to very minor movements of the controller as it shows on the indicator, i.e., small movements of the controller appear as very large movements. Even more so when the controller and drone are close together. It's no big deal, try switching thr drone to center.

This is the mode I always use. I understand both modes, but this mode is my preferred. So this isn't a mistake. But I admit the moving home point got me confused.I wasn't worry, as I had the drone right above me, but I do need to understand what has happened, and I need to be able to trust that home point.

Amit Dunsky Posted at 12-15 11:30
This is the mode I always use. I understand both modes, but this mode is my preferred. So this isn't a mistake. But I admit the moving home point got me confused.I wasn't worry, as I had the drone right above me, but I do need to understand what has happened, and I need to be able to trust that home point.

Hi Amit,

if you like post your log on here, use this > https://www.phantomhelp.com/LogViewer/Upload/
Potst the uploaded link on here.

Log shows the LatLon of the homepoint for each record, so easy check to see changes or not...

If the position of the RC is changed due to bad gps location reception, as it it in the center, the HP and Drone arrow move in the same way....

cheers
JJB

Amit Dunsky Posted at 12-15 11:24
I think I do understand you question. You're implying the movement shown is actually the RC moving in relation to the home point, and not vice versa. Is that right?

Yes, I did made the drone move ever so slightly to the sides. But all in all, it was a "go straight  up, take pictures, come back down" kind of flight, while I myself wasn't moving more than meter. Practically stationary.

Regarding, "You're implying the movement shown is actually the RC moving in relation to the home point, and not vice versa. Is that right?"

No.
I am questioning if it is possible that the controller had insufficient GPS and or location services? Meaning that it could not accurately and reliably establish its position and that that inaccuracy permitted it to seemingly drift.

I have seen something similar shown in a flight track where the drone had poor GPS at the start of the flight and then, as it climbed, the GPS improved which allowed the drone to establish its position thereby, going by the flight track, causing the drone to jump instantly from an incorrect place to the correct place.

Amit Dunsky Posted at 12-15 11:30
This is the mode I always use. I understand both modes, but this mode is my preferred. So this isn't a mistake. But I admit the moving home point got me confused.I wasn't worry, as I had the drone right above me, but I do need to understand what has happened, and I need to be able to trust that home point.

"You're implying the movement shown is actually the RC moving in relation to the home point, and not vice versa. Is that right?"
This is exactly what is happening. You probably never paid attention to it before. This is one reason I don't use this view. The farther you go from home point, the less sensitive the display is to minor controller movement.

Isn't the HP determined by the drone and its the drone and the HP thats moving around, so perhaps its the drone that couldn't see enough of the sky?

It maybe a combination of both the HP and the RC compasses not seeing enough sky prior to take off

The home point seems to be "attached" to the drone, as was moving along with it.
I have no idea how that happened. I didn't even think this was possible
It did not happen and it's not possible.

The homepoint is recorded by the drone as soon as it gets good GPS location data.
It doesn't and cannot follow the drone around.
Your flight data will show that the homepoint did not change.

You are likely confusing the controller's location with the drone's homepoint.
And if you took off from  an area with poor GPS reception, that would explain what you saw.

Post your flight data for confirmation.

Bashy Posted at 12-15 18:25
Isn't the HP determined by the drone and its the drone and the HP thats moving around, so perhaps its the drone that couldn't see enough of the sky?

It maybe a combination of both the HP and the RC compasses not seeing enough sky prior to take off

so perhaps its the drone that couldn't see enough of the sky?
Pay attention ... he got homepoint before going very far and his drone was 50-70 metres up in clear air.

Labroides Posted at 12-15 19:36
so perhaps its the drone that couldn't see enough of the sky?
Pay attention ... he got homepoint before going very far and his drone was 50-70 metres up in clear air.

I thought it was obvious that I was referring to before take off

Hi, Amit Dunsky. Thank you for reaching out. Please note that we have forwarded your concern to our related team for further checking. We will write back as soon as we receive feedback from them. Thank you for your understanding and support.

Bashy Posted at 12-15 19:43
I thought it was obvious that I was referring to before take off

I thought it was obvious that he made it clear that he got a good homepoint and the flying at 50-70 metres his drone isn't still looking for a homepoint.

DJI Tony Posted at 12-15 20:01
Hi, Amit Dunsky. Thank you for reaching out. Please note that we have forwarded your concern to our related team for further checking. We will write back as soon as we receive feedback from them. Thank you for your understanding and support.

Why?
It's obvious that the issue was his mis-interpretation of what he observed.

Labroides Posted at 12-15 20:25
I thought it was obvious that he made it clear that he got a good homepoint and the flying at 50-70 metres his drone isn't still looking for a homepoint.

You also said (of which is the same as what i SAID!)

And if you took off from  an area with poor GPS reception, that would explain what you saw.

FYI, I didn't say it was still looking for the HP, not once did i say that, don't add words that are not there.

I also ASKED a question, I did not state anything, the question mark should have been OBVIOUS!

I then surmised that it might be a combination of both prior to taking off as only half of the sky was visible to both much the same as you did.  Then theres the MAYBE part, again, i didn't state anything as fact.

So climb off your high horse and drink ya milk.

Hi there. According to our engineers, the behavior is normal. Checking the camera view, when the distance between the aircraft and the home point is less than 1m, the aircraft icon and home point icon are closer; when it is more than 3m, they are a little far. Therefore, the home point is not "attached" to the drone but rather, it is because the drone is flying too close to the home point so the icons' distance is not so obvious. if possible, kindly do another test flight and make sure that the distance is more than 20 m from the home point, and check if the same behavior is observed. Should you have any concerns or inquiries, please do not hesitate to reach us here at DJI Forum. Keep safe.

Bashy Posted at 12-15 22:41
You also said (of which is the same as what i SAID!)

And if you took off from  an area with poor GPS reception, that would explain what you saw.

You also said (of which is the same as what i SAID!)
And if you took off from  an area with poor GPS reception, that would explain what you saw.
But I was suggesting that it was the GPS reception (of his phone or tablet) down on the ground that caused the issue.
Nothing related to the GPS receiver on his drone.

I also ASKED a question, I did not state anything, the question mark should have been OBVIOUS!
Yes ... you asked a question about something that was obviously not a factor.
Something I tried to explain to you.
But as usual, any effort at explaining even simple concepts to you is futile.

I then surmised that it might be a combination of both prior to taking off as only half of the sky was visible to both much the same as you did.
But I didn't think that at all.
If you could read and understand, you'd have worked that out.
And what you surmised, didn't and couldn't happen, because you have a poor understanding of how drones work.

Labroides Posted at 12-15 23:34
You also said (of which is the same as what i SAID!)
And if you took off from  an area with poor GPS reception, that would explain what you saw.
But I was suggesting that it was the GPS reception (of his phone or tablet) down on the ground that caused the issue.

Ok, you win, congratulations, have a nice day

DJI Tony Posted at 12-15 22:59
Hi there. According to our engineers, the behavior is normal. Checking the camera view, when the distance between the aircraft and the home point is less than 1m, the aircraft icon and home point icon are closer; when it is more than 3m, they are a little far. Therefore, the home point is not "attached" to the drone but rather, it is because the drone is flying too close to the home point so the icons' distance is not so obvious. if possible, kindly do another test flight and make sure that the distance is more than 20 m from the home point, and check if the same behavior is observed. Should you have any concerns or inquiries, please do not hesitate to reach us here at DJI Forum. Keep safe.

Thank you for the information. That rules out most of the assumptions raised here, and it is important to know.
Having said that, I will try two more test flights, in a different location: The first, with similar configuration, meaning going straight up, and maintaining the drone right above the RC. The second test flight will be the same, only I will then out some distance between the drone and the RC. Hopefully, this should clarify that behavior.

I'll update the post here with the results.

Labroides Posted at 12-15 19:36
so perhaps its the drone that couldn't see enough of the sky?
Pay attention ... he got homepoint before going very far and his drone was 50-70 metres up in clear air.

Exactly!
The drone and the RC were both in the same location. It is clear from the video, that the Home Point was updated immediately after takeoff. So essentially, at that point in time, both the drone and the RC are both in the same location, same height, and experiencing the same conditions. Being that the drone easily locked in the home point, I have no reason to believe the RC would struggle with the GPS location.

This is now confirmed with the reply from DJI, describing this as a normal behavior.  So we should probably all be aware of that!

JJB* Posted at 12-15 12:00
Hi Amit,

if you like post your log on here, use this > https://www.phantomhelp.com/LogViewer/Upload/

Here's the flight log .
As can bee seen: No problem with the GPS reception, nor the compass calibration.

Link here.

Amit Dunsky Posted at 12-16 05:04
Here's the flight log .
As can bee seen: No problem with the GPS reception, nor the compass calibration.

Please tick the share box on AIrdata and post another link.
This will make the actual data available rather than just a brief summary.

Have you updated everything?

Macked Posted at 12-16 05:40
Have you updated everything?

Updating won't make any difference as there is nothing wrong.

Amit Dunsky Posted at 12-16 05:04
Here's the flight log .
As can bee seen: No problem with the GPS reception, nor the compass calibration.

Hi Amit

Your HP was set at 00.03secs and wasn't updated again, see attachment.

Your Max Home distance was 4m and 70m Max overhead. Try flying further away from HP and see if the same thing happens while moving away from HP.

I don't think there is any thing wrong.

Your Drone only went up and down in altitude and did not fly anywhere. Those. it hung over the home point.
When you moved the drone a little horizontally at the end of the video, it moved relative to the home point on the radar.
The problem was in the very beginning, when the RC remote did not catch the satellites well, so it seemed on the radar that the drone was flying.

Apparently, GPS lock isn't the problem. Scroll up a page or two, and see DJI's reply: They claim this is an expected behavior, given the very short horizontal distance between the drone and the RC.

DJI Tony Posted at 12-15 22:59
Hi there. According to our engineers, the behavior is normal. Checking the camera view, when the distance between the aircraft and the home point is less than 1m, the aircraft icon and home point icon are closer; when it is more than 3m, they are a little far. Therefore, the home point is not "attached" to the drone but rather, it is because the drone is flying too close to the home point so the icons' distance is not so obvious. if possible, kindly do another test flight and make sure that the distance is more than 20 m from the home point, and check if the same behavior is observed. Should you have any concerns or inquiries, please do not hesitate to reach us here at DJI Forum. Keep safe.

Thank you for the information.
As this maybe an expected behavior, it  is still quite confusing, and actually - doesn't make too much sense. Once the Home Point has been updated, why would a close proximity shows at the RC as if the home point is moving? Unless I'm missing something here, It doesn't make sense.. I would expect that once the Home Point has been updated, it should remain stationary on screen and doesn't move.

Amit Dunsky Posted at 12-16 15:35
Thank you for the information.
As this maybe an expected behavior, it  is still quite confusing, and actually - doesn't make too much sense. Once the Home Point has been updated, why would a close proximity shows at the RC as if the home point is moving? Unless I'm missing something here, It doesn't make sense.. I would expect that once the Home Point has been updated, it should remain stationary on screen and doesn't move.

Once the Home Point has been updated, why would a close proximity shows at the RC as if the home point is moving? Unless I'm missing something here, It doesn't make sense.. I would expect that once the Home Point has been updated, it should remain stationary on screen and doesn't move.

Once the drione has recorded its updated homepoint, it cannot and does not change.
But if the controller is in a spot where GPS reception is poor, the GPS location for the controller will be approximate and vary, thus where it is plotted can appear to wander.
If you flew from an open location where the controller had good GPS reception, it should appear stable just like the drone.

If you tick the share box in Airdata and post a new link for the Airdata report, I can show you how the drone's homepoint never changed during the flight.

Amit Dunsky Posted at 12-16 15:35
Thank you for the information.
As this maybe an expected behavior, it  is still quite confusing, and actually - doesn't make too much sense. Once the Home Point has been updated, why would a close proximity shows at the RC as if the home point is moving? Unless I'm missing something here, It doesn't make sense.. I would expect that once the Home Point has been updated, it should remain stationary on screen and doesn't move.

it makes perfect sense,
Distance is measured between two points, if one point is thought to be moving IRRESPECTIVE of whether or not it is actually moving, then the distance between the two points will be shown as changing.
Now consider that one of those two points is nominated as the centre point of a diagram, that centre point is always the centre point thus, in the diagram, the other point has to move.
It is being suggested to you that the phone and controller's position was not accurately known and that its supposed coordinates / position are thought to have been changing.
Since the controller's position was the centre point of the diagram the drone was depicted as moving.

Labroides Posted at 12-16 15:43
Once the Home Point has been updated, why would a close proximity shows at the RC as if the home point is moving? Unless I'm missing something here, It doesn't make sense.. I would expect that once the Home Point has been updated, it should remain stationary on screen and doesn't move.

Once the drione has recorded its updated homepoint, it cannot and does not change.

You assume the RC experienced poor GPS reception. But in reality, the drone registered its home point while it was hovering less than a meter "away" from the RC. This is shown in the video. So if the drone was able to lock in its position, why would you assume the RC couldn't?

The shared link has full access to the flight's data. Here's a direct link to the full flight log.It will show that the Home Point was set and never changed. It is also shown that there was no problem with the GPS reception. I suppose this rules that out.

Having said that, I wish DJI would make the RC log data available. Correlating the Drone log with the RC log could prove quite useful when investigating inflight issues.

Sean-bumble-bee Posted at 12-16 17:26
it makes perfect sense,
Distance is measured between two points, if one point is thought to be moving IRRESPECTIVE of whether or not it is actually moving, then the distance between the two points will be shown as changing.
Now consider that one of those two points is nominated as the centre point of a diagram, that centre point is always the centre point thus, in the diagram, the other point has to move.

My compass view puts the RC in the center. Not the drone.
Once the home point has been updated, AND the RC is stationary (as was the case), it doesn't make sense that the compass view is showing it wandering all over.
The compass view shows three indications: The Home Point location, The RC location and the Drone location. So there is no sense in having the home point moving.

Amit Dunsky Posted at 12-16 23:46
My compass view puts the RC in the center. Not the drone.
Once the home point has been updated, AND the RC is stationary (as was the case), it doesn't make sense that the compass view is showing it wandering all over.
The compass view shows three indications: The Home Point location, The RC location and the Drone location. So there is no sense in having the home point moving.

"My compass view puts the RC in the center. Not the drone, " so, if the the system thinks that one or both the RC and/or the drone moves and the distance between them changes, please explain how you think the diagram should depict the situation?

Try a very simple experiment.
Go somewhere safe, launch the drone and let it hover at between one and two metres above the ground, point the camera at the ground and start recording video. Start a screen capture on the screen device. Taking the controller with you, walk away from the drone and leave the drone hovering over the launch point, what is shown happening on you "compass view"?

Amit Dunsky Posted at 12-16 23:39
You assume the RC experienced poor GPS reception. But in reality, the drone registered its home point while it was hovering less than a meter "away" from the RC. This is shown in the video. So if the drone was able to lock in its position, why would you assume the RC couldn't?

The shared link has full access to the flight's data. Here's a direct link to the full flight log.It will show that the Home Point was set and never changed. It is also shown that there was no problem with the GPS reception. I suppose this rules that out.

You assume the RC experienced poor GPS reception.
So if the drone was able to lock in its position, why would you assume the RC couldn't?
Mostly because you mentioned that you were " standing in a rather tight space".
Your phone/tablet or controller has a different receiver and antenna, possibly not as good as that in th drone.
Also it was difficult to properly understand what the issue was that you thought you discovered.
The drone was never more than 3.7 metres away (horizontally)  from the home point - it was virtually right above the home point so neither was moving relative to the other to any appreciiable degree.
On the scale of the compass view, the drone, home point and controller location would have been one dot if plotted accurately

It will show that the Home Point was set and never changed.
It does.
Home point when updated at 0:02.6 sec was   32.58325  34.95265
Home point at end of flight 9:01.6 was  32.58325  34.95265
The home point was the same for each of the 2700 lines of data, just as it should be.
Home points don't change during a flightunless you change them.

Having said that, I wish DJI would make the RC log data available. Correlating the Drone log with the RC log could prove quite useful when investigating inflight issues.
Not really.
The locations that matter in the flight data are those of the drone and the home point.
Where you might move with the controller during a flight makes no difference.
Including that data would only confuse things unnecessarily.

Sean-bumble-bee Posted at 12-17 00:16
"My compass view puts the RC in the center. Not the drone, " so, if the the system thinks that one or both the RC and/or the drone moves and the distance between them changes, please explain how you think the diagram should depict the situation?

Try a very simple experiment.

Because the Drone location, the RC location and the Home Point location are each represented separately on the compass. So, I understand when the drone location is moving. I understand the RC location is moving - I get that a lot when I'm changing location or even when changing my heading. But the home point location is irrespective to neither once it is set, thus shouldn't move in that specific compass view I use, unless the RC is moving away from it - which in this specific case it didn't.
It just doesn't make any sense, and I bet it is a bug.

Amit Dunsky Posted at 12-17 00:45
Because the Drone location, the RC location and the Home Point location are each represented separately on the compass. So, I understand when the drone location is moving. I understand the RC location is moving - I get that a lot when I'm changing location or even when changing my heading. But the home point location is irrespective to neither once it is set, thus shouldn't move in that specific compass view I use, unless the RC is moving away from it - which in this specific case it didn't.
It just doesn't make any sense, and I bet it is a bug.

When you are standing right beside the launch point, both are for all intents and purposes, the same point and can't be shown independently.
Forget about this whole thread, it's something about nothing.

Amit Dunsky Posted at 12-17 00:45
Because the Drone location, the RC location and the Home Point location are each represented separately on the compass. So, I understand when the drone location is moving. I understand the RC location is moving - I get that a lot when I'm changing location or even when changing my heading. But the home point location is irrespective to neither once it is set, thus shouldn't move in that specific compass view I use, unless the RC is moving away from it - which in this specific case it didn't.
It just doesn't make any sense, and I bet it is a bug.

Hi Amit

Just understand post #8....
Log will show RC LatLon position changing. (so why don`t you share your flightlog)

cheers
JJB