I’m having a problem where I have to re-calibrate the IMU on my Mavic 3 Cine almost every time I fly. If I don’t, my return-to-home function lands the drone 10 to 50 feet away from my landing pad. once I recalibrate the IMU, it lands in the right place. Sometimes I don’t have to re-calibrate for maybe a week or so. But one day it will be landing right on the landing pad, and the next day it will land on my roof.  All of these tests are from my deck, in the same location. There are no large metallic objects in the vicinity of the deck. I have three other DJI drones (Mavic pro, Air 2S, Mini 2) that never need their IMU recalibrated. Does anybody else have this problem? I have searched the Internet, but can't find anybody else experiencing this problem.

When the homepoint is 'wonky' are you certain the drone had sufficient GPS at take off to set the homepoint to the take off point?
I don't have a Mavic 3 but, with my DJI drones, I have the impression that even if the drone has a home point whilst on the ground it resets the homepoint immediately after take off.

If you take off with insufficient GPS the homepoint will be set to the place wherever the drone first gains sufficient GPS.
Then either
a) manually bring the drone back over head and reset the home point to the drone's position or,
b) if the controller knows its own location, the controller's location.
I prefer using a).

I probably should have stated that I do ensure that I have good GPS-lock, and that the controller tells me that "the home-point has been updated." And then I take-off, climb slowly straight up to about 50 feet before moving forward. The precision-landing system records its landing information at about 20 feet I believe. I have tested the RTH capabilities numerous times under fairly controlled conditions.

Then the next step is to post the flight log for an errant flight.
Just incase you do not know how to do that, go to https://www.phantomhelp.com/LogViewer/Upload/
where you will find suitable instructions, upload the log then paste the resulting URL here.

IMU has nothing to do with the accuracy of the drone on RTH, except to maintain correct attitude of the craft. it’s likely GPS is your issue. Are you waiting for homepoint lock ?

Im just wondering how you even thought IMU was the problem, are getting warnings to calibrate IMU ?

Calibrating the IMU fixes the problem -- every time. That is the only way I can get RTH to begin working again. I figured it was the IMU since the only things I can calibrate are the IMU and the compass. Calibrating the compass doesn't fix the problem. Calibrating the IMU does. The gps locks-in with about 25--27 satellites in approximately 30--60 seconds from a cold start. The homepoint appears to be correct on the map. The drone just can't always fly to it. And when the drone can't find the homepoint, the only way to get it to find it again is an IMU calibration. This gives me an idea for a test. Next time it can't find the homepoint, I'll land it manually, shut it off, start it up again, take-off straight up, and see what happens when I hit the RTH button. If it flies away from the launch pad, that may be an indication of a gps issue.

gary h Posted at 7-21 16:06
Calibrating the IMU fixes the problem -- every time. That is the only way I can get RTH to begin working again. I figured it was the IMU since the only things I can calibrate are the IMU and the compass. Calibrating the compass doesn't fix the problem. Calibrating the IMU does. The gps locks-in with about 25--27 satellites in approximately 30--60 seconds from a cold start. The homepoint appears to be correct on the map. The drone just can't always fly to it. And when the drone can't find the homepoint, the only way to get it to find it again is an IMU calibration. This gives me an idea for a test. Next time it can't find the homepoint, I'll land it manually, shut it off, start it up again, take-off straight up, and see what happens when I hit the RTH button. If it flies away from the launch pad, that may be an indication of a gps issue.

Just wondering, you say you fly from your Deck, is the Deck elevated or land level?

The deck is elevated 8 to 10 feet above the ground. I take off from the deck and land on the deck in the same location. I also have three other drones that don’t experience a problem when using the automated RTH function. I never have to calibrate the IMU with these drones when flying in the same location. I fly from this location a lot.

gary h Posted at 7-21 16:06
Calibrating the IMU fixes the problem -- every time. That is the only way I can get RTH to begin working again. I figured it was the IMU since the only things I can calibrate are the IMU and the compass. Calibrating the compass doesn't fix the problem. Calibrating the IMU does. The gps locks-in with about 25--27 satellites in approximately 30--60 seconds from a cold start. The homepoint appears to be correct on the map. The drone just can't always fly to it. And when the drone can't find the homepoint, the only way to get it to find it again is an IMU calibration. This gives me an idea for a test. Next time it can't find the homepoint, I'll land it manually, shut it off, start it up again, take-off straight up, and see what happens when I hit the RTH button. If it flies away from the launch pad, that may be an indication of a gps issue.

Calibrating the IMU fixes the problem -- every time.  That is the only way I can get RTH to begin working again
Calibrating the IMU or compass is 100% not related to RTH autolanding accuracy.

That is the only way I can get RTH to begin working again. I figured it was the IMU since the only things I can calibrate are the IMU and the compass. Calibrating the compass doesn't fix the problem. Calibrating the IMU does.
There's normally never any need to recalibrate either the compass or the IMU and if they needed recalibrating, you'd know about it, because the drone wouldn't fly properly and you'd have warnings on your screen.

The homepoint appears to be correct on the map. The drone just can't always fly to it. And when the drone can't find the homepoint, the only way to get it to find it again is an IMU calibration.
This can't be correct.
The drone records its homepoint and can always find it's way to that homepoint.
And the IMU has nothing to do with it.

This gives me an idea for a test.
Here's a much better idea.
You need to identify the actual cause of the perceived issue and address that.
The way to do this is to post the recorded flight data from one of the flights where you feel the drone can't fly to the homepoint.
That will show exactly where and when the homepoint was recorded and also show how close teh drone "thinks" it is to the home point when it comes home.
I'm pretty sure that it will reveal a simple explanation for what you have experienced and help you to avoid it in future.

To post your flight data ...
Go to: https://www.phantomhelp.com/LogViewer/Upload/
... where you'll find instructions to upload the data to that site and it will give a report
For help interpreting the data you can post a link for the report here.
Or just post the .txt file.

ps The elevation of the deck has nothing to do with the issue you've observed.

I'm using an RC Pro controller. I connected that to my windows PC, opened up both of the available drives. No files are visible on either drive, even though one of the drives says it is about 80% filled. The other drive is in fact empty. All of the folder icons appear as empty folders, and upon opening them, no files are visible. I tried to see if I could enable the visibility of the files via windows. I know there is data in the folders, but I cannot see any of it as of yet.

gary h Posted at 7-21 19:15
I'm using an RC Pro controller. I connected that to my windows PC, opened up both of the available drives. No files are visible on either drive, even though one of the drives says it is about 80% filled. The other drive is in fact empty. All of the folder icons appear as empty folders, and upon opening them, no files are visible. I tried to see if I could enable the visibility of the files via windows. I know there is data in the folders, but I cannot see any of it as of yet.

When you connect an Android device, by default the connection only allows charging.
You have to enable transferring files to get access to the files.
You get to the right menu item by swiping down from the top of the screen.
Perhaps that's the problem?

Here's what that looks like on an Android phone.
It should be similar on your controller.

I have seen such USB options on my Samsung Note 10 Android phone (although not by swiping down) these options don't appear on the RC Pro controller by swiping down. I looked through the settings within the RC Pro and couldn't immediately locate these option, but I'll keep looking. Although the RC Pro is an Android device, it does not contain all the options as an Android phone. The Android OS has been streamlined to contain only that which is essential as determined by DJI.

Labroides -- I flew the drone several times today and tested the RTH when landing. Every time it landed within 2--4 inches of the center of the drone's launch pad. I flew again just now, about three hours after the last successful flight and landing. The drone was about 100 feet north of its landing pad and I clicked on RTH. The drone proceeded to attempt an auto-landing 28.9 feet north of the landing pad. So I went into the settings of the RC Pro to see where the home point was set. According to the map, the home point was located correctly in the middle of the deck on the south side of the house, which is exactly where I took-off from, and from where I locked-in the home point. But that is not where the drone tried to land. It tried to land on the north end of the house, 28.9 feet from the home point. This time I did not perform an IMU calibration, but instead flew the drone to  about three feet above the landing pad and told the drone to update its home point to this location. I then climbed to about 50 feet in altitude and flew away to the south. Upon executing RTH again, the drone landed in the proper location. I repeated taking-off and landing several more times and all worked fine. I still haven't been successful in retrieving the controller logs, but will eventually figure it out. I suppose it's possible there is a problem with the GPS. The Mavic 3s have had GPS problems since their November 2021 launch, but all has supposedly been fixed with a firmware released in May 2022. The problem did not involve accuracy, but instead had to do with how long the drones were taking to lock-in a home point. Times were taking multiple minutes, up to maybe 5--10 or more. I haven't heard that anybody else is having an RTH accuracy problem with their Mavic 3s.

gary h Posted at 7-22 20:07
Labroides -- I flew the drone several times today and tested the RTH when landing. Every time it landed within 2--4 inches of the center of the drone's launch pad. I flew again just now, about three hours after the last successful flight and landing. The drone was about 100 feet north of its landing pad and I clicked on RTH. The drone proceeded to attempt an auto-landing 28.9 feet north of the landing pad. So I went into the settings of the RC Pro to see where the home point was set. According to the map, the home point was located correctly in the middle of the deck on the south side of the house, which is exactly where I took-off from, and from where I locked-in the home point. But that is not where the drone tried to land. It tried to land on the north end of the house, 28.9 feet from the home point. This time I did not perform an IMU calibration, but instead flew the drone to  about three feet above the landing pad and told the drone to update its home point to this location. I then climbed to about 50 feet in altitude and flew away to the south. Upon executing RTH again, the drone landed in the proper location. I repeated taking-off and landing several more times and all worked fine. I still haven't been successful in retrieving the controller logs, but will eventually figure it out. I suppose it's possible there is a problem with the GPS. The Mavic 3s have had GPS problems since their November 2021 launch, but all has supposedly been fixed with a firmware released in May 2022. The problem did not involve accuracy, but instead had to do with how long the drones were taking to lock-in a home point. Times were taking multiple minutes, up to maybe 5--10 or more. I haven't heard that anybody else is having an RTH accuracy problem with their Mavic 3s.

But that is not where the drone tried to land. It tried to land on the north end of the house, 28.9 feet from the home point.
RTH is very, very reliable.
It doesn't randomly land in odd places.
There will be a simple explanation waiting to be found in your flight data.

I still haven't been successful in retrieving the controller logs, but will eventually figure it out.
I don't have one of those controllers to check, but others have managed to get flight data from them so it must be possible.
Did you see these detailed instructions for some of DJI's other integrated tablet/controllers?
https://forum.phantomhelp.com/t/ ... o-your-computer/256
Yours should work in a similar way.

I suppose it's possible there is a problem with the GPS. ...
The Mavic 3 GPS issues were solved a couple of months back.
But they weren't about GPS accuracy.
If you have up-to-date firmware, your M3's GPS should be working as well as (or better than) any other DJI drone.

What's your launch point like with respect to having a clear skyview for satellite reception?
Is there a clear horizon everywhere you look or is much of the sky blocked by buildings, trees etc?
I don't like guessing, but what I suspect might be happening is that the drone isn't recording a homepoint before launch, or GPS is marginal there and it records a tentative homepoint and a little later updates that when it gets good GPS reception as it's flying out.
The recorded data will quickly show if it's that or if not, what is actually happening.

That link for the Phantom did not help. First of all, the directory structure on the RC Pro doesn't match. But even if it matched perfectly, upon connecting the controller to my computer, all the directories within the controller appear blank. I will look for info online about how others are retrieving their log data.

I do have up-to-date firmware. I update all drone and RC Pro firmware and the FLY app whenever updates are available.

My horizon is clear enough. I can get 17--25 satellites inside my house with three-feet of snow on my roof, and can record a home point in-doors in about a minute. Outdoors on the deck signals are stronger, number of satellites are greater, and home-point lock occurs in 30 to 60 seconds. My location is not a problem I also have a Mavic 2 Pro, a Mini 2, and an Air 2S. These three drones have no problem returning properly when using RTH. The example I provided today invalidates the theory that the drone isn't recording a home point before launch. In fact, it records the home point upon initial satellite lock, and then it updates it again as soon as the drone lifts-off straight up beyond the seven-meter height required for "precision landing" to properly capture an image via its sensors, of the launch pad against the deck floor. Also, upon reviewing the settings within the RC Pro, as to where the home point was recorded, while the drone was hovering 30 feet north of the launch pad, the map in the controller was showing me that the home point was still located where it was originally recorded, 30 feet to the south of the hovering drone, right in the middle of the deck,  where it was supposed to be. The RTH function was in fact sending the drone to where the home point was not.

regarding the logs' location, you might like to look at have a look at https://mavicpilots.com/forums/dji-rc-pro-controller.202/

do you sync your logs? If so an alternative approach that might work would be to install the app on a phone, log in to the app (using the same details that are used on the controller)  on that phone and then allow sync'ing on the phone's app, I believe  that will download logs that have been synced from the controller to DJI but which are not on the phone, to the phone

gary h Posted at 7-22 23:33
That link for the Phantom did not help. First of all, the directory structure on the RC Pro doesn't match. But even if it matched perfectly, upon connecting the controller to my computer, all the directories within the controller appear blank. I will look for info online about how others are retrieving their log data.

I do have up-to-date firmware. I update all drone and RC Pro firmware and the FLY app whenever updates are available.

Then we need to see what the recorded flight data shows to find out what's going on.
Without that, there's not much chance of a resolution.

gary h Posted at 7-22 23:33
That link for the Phantom did not help. First of all, the directory structure on the RC Pro doesn't match. But even if it matched perfectly, upon connecting the controller to my computer, all the directories within the controller appear blank. I will look for info online about how others are retrieving their log data.

I do have up-to-date firmware. I update all drone and RC Pro firmware and the FLY app whenever updates are available.

You need to post flight logs. Incidentally have you tried resetting homepoint after your drone establishes first home point this should set it to your position. Its lets say a temporary fix until you find out what’s going on.

The home point is being set in the proper place. It is being set in the middle of the deck. There is no need to manually reset it, because it always sets correctly. And then occasionally when executing RTH, the drone does not return to the established home point. It lands in some random location around my house.

Are you going to post the flight log?

I'm still trying to figure out how to get the flight logs out of the controller. A previous suggestion was to set the controller in its USB settings to "File Transfer." I just found those settings, and it is set for "File Transfer. However, all directories on the controller appear as empty folders. I did replay the graphical representation of the flight logs on the controller, and it appears that when I launch the drone, the home point is not in the same location as the drone. In this last flight I described, the home point started out over the roof of the house to the north. Then after the faulty attempt at RTH, the home point moved over to the deck. I'm still trying to find a way to get the logs out of the controller.


I just tried connecting my older, original smart controller to the computer to view the files. The same thing occured with the older controller. Only empty folders were visible. And this older controller was also set for "file transfer."

Update 1: I can see files on my Samsung Android phone, but I cannot see any files on my DJI Smart Controller, nor my DJI RC Pro controller.

Update 2: I just flew the drone again. I set the drone in the middle of the launchpad and started it. I switched over to map view, and with the drone sitting on the launchpad, the drone said "home point updated." But the home point was actually not where the drone was sitting on the deck. Instead, the home point locked-in about 30 feet NE of the drone's location. I then started the motors on the drone and began to take off. The drone again said "home point updated." This time the home point was correctly recorded in the middle of the deck. From now on I will check the drone's homepoint location before I take off, and before I land. This way I should be able to identify what is going on if/when the RTH fails again.

gary h Posted at 7-23 09:46
I'm still trying to figure out how to get the flight logs out of the controller. A previous suggestion was to set the controller in its USB settings to "File Transfer." I just found those settings, and it is set for "File Transfer. However, all directories on the controller appear as empty folders. I did replay the graphical representation of the flight logs on the controller, and it appears that when I launch the drone, the home point is not in the same location as the drone. In this last flight I described, the home point started out over the roof of the house to the north. Then after the faulty attempt at RTH, the home point moved over to the deck. I'm still trying to find a way to get the logs out of the controller.

However, all directories on the controller appear as empty folders.
Make sure that you are looking in the correct location.
For the current version of DJI Fly, you need to look in:  

Android\data\dji.go.v5\files\FlightRecord

You can also open a free Airdata account. And link to the flights there.

https://www.phantomhelp.com/LogViewer/0XFKXJPKV2BOW99BHYY3
I have posted the flight log. This doesn't seem to be as helpful as the looking at the animated log tool in the controller. That shows me that the drone appears to take off from the roof 30 feet to the north of where it actually takes off from. It also shows that the drone tries to land on the roof, 30 feet from where it was supposed to land. Then I see that I perform a home point reset, and then the home point moves to where it actually took off from, the deck, to the south of the house.

NOTE: There are several RTHs in this flight. The first one is the only problematic one (this one shows the drone launching from and landing on the roof. It did not actually launch from the roof, but it did try to land via RTH on the roof. I had to stop it and land it manually.) All the rest of the RTHs performed as they were supposed to, launching from and landing onto the deck.

gary h Posted at 7-23 16:56
https://www.phantomhelp.com/LogViewer/0XFKXJPKV2BOW99BHYY3
I have posted the flight log. This doesn't seem to be as helpful as the looking at the animated log tool in the controller. That shows me that the drone appears to take off from the roof 30 feet to the north of where it actually takes off from. It also shows that the drone tries to land on the roof, 30 feet from where it was supposed to land. Then I see that I perform a home point reset, and then the home point moves to where it actually took off from, the deck, to the south of the house.

Your drone shows marginal GPS location data after startup and did not record a homepoint until 10.6 seconds.
The flight data shows in the first RTH, the drone reached a point directly above the recorded homepoint at 5:46.4 and started descending.
At 5:57.2 it looks like you cancelled RTH with VPS indicating it was 20 feet above something and left the drone hovering.

At 7:10.2 you gave joystick input to fly the drone away from the recorded homepoint.
This took the drone 34 feet from the recorded homepoint, with VPS now showing the drone was 32 feet above something
You left it hovering there.

At 8:42.6, while in RTH, the homepoint was changed to somewhere 32.5 feet away from the original home point.
You flew around for a while and at 9:25.6 you initiated RTH and cancelled it at 9:57.4 with the drone 22 ft above the new home point.
You left it hovering until 12:05.0 when you resumed control and brought the drone down at the new home point.


.

gary h Posted at 7-23 16:56
https://www.phantomhelp.com/LogViewer/0XFKXJPKV2BOW99BHYY3
I have posted the flight log. This doesn't seem to be as helpful as the looking at the animated log tool in the controller. That shows me that the drone appears to take off from the roof 30 feet to the north of where it actually takes off from. It also shows that the drone tries to land on the roof, 30 feet from where it was supposed to land. Then I see that I perform a home point reset, and then the home point moves to where it actually took off from, the deck, to the south of the house.

Some more detail ....

Normally the drone's flight controller assesses the reliability of the location data from the GPS, and when it rates the location data reliability as 4/5 or better, it indicates the drone is ready to fly (the GPS icon on screen changes to white) and it records a home point.

In this flight, the FC assessed location data as 5/5 after 2.4 seconds and started recording distance (from home) but there is no indication of a homepoint being recorded until 10.6 seconds wnen you launched.

From 2.4 to 10.6 seconds, with the drone sitting at the launch point, the distance showing kept moving from 0 to 13 feet before the homepoint was recorded.
This suggests less than optimum GPS reception early in the flight.

You say that the drone tried to land 30 ft from where it was launched, but the data shows the same location at that landing as at launching.
This points to an inaccurate homepoint being recorded.
The reason isn't clear, but perhaps there is something about the launch point that makes it less than optimum for GPS reception?

Yes it does show the same launch point and landing point on the first return to home. But unfortunately, this launch point and landing point is on the slope of the roof behind me, to which I have no access. Clearly I did NOT launch the drone from a sloped roof ten feet above my head. I also did not land it in that location. This is the error that I periodically experience. Also, I’m in a residential area with other houses quite distant from me. I don’t know of anything that would be interfering with the GPS on the Mavic 3. This problem only affects the Mavic 3. My other three drones don’t have any problems with the GPS. This is what makes me think it is a problem with my particular unit.

gary h Posted at 7-23 20:01
Yes it does show the same launch point and landing point on the first return to home. But unfortunately, this launch point and landing point is on the slope of the roof behind me, to which I have no access. Clearly I did NOT launch the drone from a sloped roof ten feet above my head. I also did not land it in that location. This is the error that I periodically experience. Also, I’m in a residential area with other houses quite distant from me. I don’t know of anything that would be interfering with the GPS on the Mavic 3. This problem only affects the Mavic 3. My other three drones don’t have any problems with the GPS. This is what makes me think it is a problem with my particular unit.

Clearly I did NOT launch the drone from a sloped roof ten feet above my head. I also did not land it in that location.
Which is why I suggested a possible GPS issue at that spot.
It's unlikely that there's a problem with the GPS unit in the drone.
GPS works or it doesn't, but it doesn't give flaky data without some outside factor causing that.

How many times have you observed this issue?
Have you also launched this drone from the same spot without a problem?

Below is a better picture of the house as shown in the log viewer. You can clearly see the deck and the launch pad from which all flights originated. You can also see the roof, where the flight logs say the drone launched from. Needless to say, I don't climb up on my roof to launch the drone. And it wouldn't launch (or land) on such a sloped roof anyway.

Labroides Posted at 7-23 20:20
Clearly I did NOT launch the drone from a sloped roof ten feet above my head. I also did not land it in that location.
Which is why I suggested a possible GPS issue at that spot.
It's unlikely that there's a problem with the GPS unit in the drone.

This is an intermittent problem.  I have launched from this location hundreds of times from -20 degrees Fahrenheit, to +80 degrees Fahrenheit. Probably 95% of the time RTH works fine. Maybe 5% or less I experience this problem.

gary h Posted at 7-23 21:35
This is an intermittent problem.  I have launched from this location hundreds of times from -20 degrees Fahrenheit, to +80 degrees Fahrenheit. Probably 95% of the time RTH works fine. Maybe 5% or less I experience this problem.

Temperature has no effect on GPS reception.
But the amount of sky/horizon that's blocked by the house walls and roof might.
The sats are always moving across the sky so the distribution of sats in the sky will be different every hour and every day.
You need a wide spread for accurate location data.
If you happen to have a day when the drone can only get sats clustered in one part of the sky, that can account for marginal data accuracy.

The data you posted shows it was only picking up 15-16 sats at the launch spot.
That's quite low for the Mavic 3 which receives GPS signal from 3 different systems.
Looking at the most recent 10 flights I've made ... launching in the open, I'm picking up 24-30 sats within a few seconds.

I guess I'll just pay attention each time I launch and land to see if I can see an erroneous home point location on the map. Then I will at least know when it happens and will be able to manually update the home point. Something is causing this. I have to figure out if the drone has a problem, or if somehow it's my location.

gary h Posted at 7-24 09:20
I guess I'll just pay attention each time I launch and land to see if I can see an erroneous home point location on the map. Then I will at least know when it happens and will be able to manually update the home point. Something is causing this. I have to figure out if the drone has a problem, or if somehow it's my location.

Try some launches from a place where the drone has >75% of the horizon unobstructed and compare the sat numbers you are getting.

I will. I'm sure the numbers will be higher, because I can see the number of satellites increase as I climb in altitude. Seems like the drone should know when it has locked onto sufficient satellites for accurate position information. One thing I've wondered is if the number of satellites reported by the controller includes satellites from more than one constellation. If so, then 10 satellites should be plenty for accurate position information. With the U.S. system, three satellites will give you location along the "x" and "y" axis , but it takes four satellites to also give you height information on the "z" axis.  It would be nice if the controller would tell us which system we are locked-in to. Thanks for you help.

gary h Posted at 7-24 10:29
I will. I'm sure the numbers will be higher, because I can see the number of satellites increase as I climb in altitude. Seems like the drone should know when it has locked onto sufficient satellites for accurate position information. One thing I've wondered is if the number of satellites reported by the controller includes satellites from more than one constellation. If so, then 10 satellites should be plenty for accurate position information. With the U.S. system, three satellites will give you location along the "x" and "y" axis , but it takes four satellites to also give you height information on the "z" axis.  It would be nice if the controller would tell us which system we are locked-in to. Thanks for you help.

Seems like the drone should know when it has locked onto sufficient satellites for accurate position information.
The drone knows when the position information is acceptable and the GPS icon changes to white when that happens.
But it's not a simple matter of the number of satellites.
Lots of sats isn't enough unless you have a good spread.
Sats that are bunched don't count for much, and when you have a large part of the sky obstructed, you get more that are bunched up.

One thing I've wondered is if the number of satellites reported by the controller includes satellites from more than one constellation.
It's the total number from all constellations.

If so, then 10 satellites should be plenty for accurate position information.
That's a common misconception and gets repeated often here.
But the number is not very important.
In some situations, 10 will be more than enough, and in others it won't be enough.

It would be nice if the controller would tell us which system we are locked-in to.
It's receiving data from all available sats.

gary h Posted at 7-24 10:29
I will. I'm sure the numbers will be higher, because I can see the number of satellites increase as I climb in altitude. Seems like the drone should know when it has locked onto sufficient satellites for accurate position information. One thing I've wondered is if the number of satellites reported by the controller includes satellites from more than one constellation. If so, then 10 satellites should be plenty for accurate position information. With the U.S. system, three satellites will give you location along the "x" and "y" axis , but it takes four satellites to also give you height information on the "z" axis.  It would be nice if the controller would tell us which system we are locked-in to. Thanks for you help.

Hi,

In addition the Labroides analysis some figures to comfirm his findings

At 2.4 GPS data stored into drone, HP data, see green markings.
But GPS data fluctuates, see LAT LON (#3 #4 column)....M3 on the ground and only vertical take-off
That is why the distance to HP (column HD) is changing value.

At 10.6s HP updated (just in air), so the distance to zero as M3 is zero distance from HP setting.

Normally when the GPS icon turns from amber (enough sats for GPS lock) into White (GPS lock + HP is set) the Drone LAT LON values are steady figures. Not in this start of a flight.
See my charts of your data.
Cannot say more about Drone GPS LatLon after applying forward stick.

Question to be asked ; why aren`t the M3 GPS LatLon not steady ?  signal reflections near buildings can have this effect.

Cheers
JJB

JJB -- I'm not understanding all of what you wrote. What does the abbreviations "M3" and "HD" stand for?
Also, what software created these two tables? I downloaded the .KMZ file and loaded it into Google Earth. Very interesting 3D image of the flight, although I'm not quite sure how to interpret all the parts. Some might be what you are questioning in these two tables.

gary h Posted at 7-24 13:55
JJB -- I'm not understanding all of what you wrote. What does the abbreviations "M3" and "HD" stand for?
Also, what software created these two tables? I downloaded the .KMZ file and loaded it into Google Earth. Very interesting 3D image of the flight, although I'm not quite sure how to interpret all the parts. Some might be what you are questioning in these two tables.

M3 = Mavic 3 HP= Homepoint

JJB -- Thanks. What software package did you use to create those tables?

gary h Posted at 7-24 13:55
JJB -- I'm not understanding all of what you wrote. What does the abbreviations "M3" and "HD" stand for?
Also, what software created these two tables? I downloaded the .KMZ file and loaded it into Google Earth. Very interesting 3D image of the flight, although I'm not quite sure how to interpret all the parts. Some might be what you are questioning in these two tables.

Hi Gary,

wich part did you not fully understand? so i can try to explain better.

M3 = Mavic3, HD in my chart is HomeDistance.
In this column the actual GPS distance per record shown Drone to HomePoint.

I use my own analysis software, not only for showing data as in the log but all extra options and checks ; make its easier not to miss an 'error' in logs.Search for FRAP (name of the program) on this forum.
Soon an update with more checks in it.

FRAP makes its own kml files.....
Polar chart of your flight as an example.

cheers
JJB