My HOMEPOINT position (H) in DJI Go app shows me in wrong place, normal ?

[KONY]

that's even more disturbing when , like in my case, you hear that robotic voice telling you ''homepoint location has been recorded. ready to take off"

you would assume that it had recorded your actual precised location...

 

[msinger]

you would assume that it had recorded your actual precised location...

In your case, the home point was correctly marked according to your Mavic. I don't know why the home point is showing in the wrong location on the map. It seems to be showing in the location where your phone thinks it's located.

 

[KONY]

In your case, the home point was correctly marked according to your Mavic. I don't know why the home point is showing in the wrong location on the map. It seems to be showing in the location where your phone thinks it's located.

i understand that, but why the DJI Go app required me to switch ON the phone's GPS to display that MAP if MAVIC's GPS could be sufficient to display it ?

it seems to be different for you. Is that some specific ANDROID Vs IOS ?

I'm on android.

I'd rather only rely on Mavic's GPS if it's more reliable than what the phone would provide.

 

[msinger]

i understand that, but why the DJI Go app required me to switch ON the phone's GPS to display that MAP if MAVIC's GPS could be sufficient to display it ?

I'm not sure. I only have Android tablets. All of them have GPS. When I disable GPS via "Settings" --> "Location", I'm still able to see the maps as long as Wi-Fi is enabled. I don't see a prompt to turn on GPS in DJI GO.

I'd rather only rely on Mavic's GPS if it's more reliable than what the phone would provide.

The Mavic does not set its home point on startup using data from your mobile device. You can confirm that by viewing the recorded home point in your flight log.

 

[KONY]

ok thank you msinger, maybe something went wrong, next time i'll pay attention to this again and see if i can ignore the prompt to switch on the phone's GPS

 

[Rflush]

I have this happen to me very often, showing my home point a few metres away from where I am actually standing.
I think it's just a map error, when I initiated a RTH it will come back to my standing location, even if the map shows my homepoint is not where I am standing. The mavic will just go to the H that's on the map, and even if it shows somewhere different, it's always where I am standing.

 

[John Shaw]

So how do you pause and reset home ?
I had the same thing happen yesterday, I drove to a new location had rotors stopped but upon lift off I noticed it still had old location on map as home, 2 miles away. this was even after I recalibrated compass
I will admit I was not sure if I was doing calibration correctly but I did have "ready to go on" screen. I called it a day and gave up.

Clarification: You can do a reset of the home position with the Litchi app. I should keep my apps straight and clarify.

 

[Kilrah]

It looks like everything's correct but the map data is off.

I tend to trust what I see, so in such a circumstance I'd just fly 100m out, press RTH, and see if it comes at the right place. If yes the source of the problem is obvious.

 

[AndyT.hk]

indeed , i typed those in GOOGLE MAP and it directs to my exact location...then why the "internal DJI GO APP MAP" shows something else...which one is used for the RTH ?

Also you told me earlier that switching ON the phone's GPS does not matter because the Aircraft uses its own GPS but i noticed this : whenever, after switching on the Remote controler once, i clicked on the map at the left bottom on the screen of my smartphone, it would pop up a message asking me to switch on the phone's GPS.

Only after that it will display the map on DJI GO APP.

Tha's weird then

Having finally received my Mavic, I'm also having a few "home" issues. Looking at you Lat/Long in Aberdeen I was wondering if this is a China issue and tried switching the China GPS options. No change. I'm in the NT but the map shows me maybe 2km SE of where I actually live on the other side of the main road. So I'm kinda nervous about hitting RTH if it's going to runaway. I'm not sure if this is map shift or a co-ordinates issue. Reading this thread, I guess I need to extract the flight log and see what that tells.

Otherwise all going well and enjoying myself; maybe need to find a bit more room....

Cheers, Andy

 

[KONY]

yes definately check the coordonates like msinger proposed and past them in google map
also do the test suggested by the previous post #28, i'll do that too when i can fly again.

The good thing is you can STOP RTH procedure at any time and take control back of the MAVIC if it's going the wrong way

 

[AndyT.hk]

yes definately check the coordonates like msinger proposed and past them in google map
also do the test suggested by the previous post #28, i'll do that too when i can fly again.

The good thing is you can STOP RTH procedure at any time and take control back of the MAVIC if it's going the wrong way

I just need to find that CSV file cos the flight log doesn't seem to contain info. Or do I need everything connected?

 

[KONY]

u have to upload the text log file there :

https://www.phantomhelp.com/LogViewer/Upload/

then from the link u can download the CSV

the log text file can be obtained by diving into the DJI folder or your phone/tablet you used to fly

 

[AndyT.hk]

u have to upload the text log file there :

https://www.phantomhelp.com/LogViewer/Upload/

then from the link u can download the CSV

the log text file can be obtained by diving into the DJI folder or your phone/tablet you used to fly

(e.g. "DJIFlightRecord_2016-02-12_[15-33-10].txt")

That file is on my drone? I only see mov/jpg files. Or on my phone? I see the flight log list but they don't seem to open.

Meantime, gotta go to the movies with the family.

Thanks

 

[KONY]

i took that file from my phone

 

[Rflush]

Enter your device via the app without connecting to your drone, take a look at the map and see if the location is right. Mine always shows it's wrong, but it's just a visual error.

 

[JohnC]

I am sure this has been covered before, here goes anyway, GPS accuracy is dependent only many factors, including the GPS system itself & the quality of the recievers. Cloud cover, buildings and heavy radio interference can cause issues with it. The US Gov can also downgrade the accuracy of it if they so wish, these events are usually in a NOTAM (Notice to Air Men) which can be found on the internet if you have a look. In the UK, there are quite often GPS jamming trials, which again are NOTAM'd mainly around the tactical ranges in Northern England. All this can cause havoc with GPS receivers.

Not so long ago accuracy for GPS available for public use was limited to about 50-100 meters, the system was programmed to add mis timings into the data stream so that 'hostiles' could not use the system to attack the US and its allies. Only the approved military users knew when these mistimings would occur and therefor be able to filter them out to generate a high accuracy location.

If you recorded the position returns on a receiver in the late 80's your position created a wonderful Daisy pattern if you plotted it as the errors came and went.

For us drone pilots there are two factors at play with the equipment, the Drone records its location once it has a good 'lock' and then uses this as a viable home point, depending on how many GPS satellites it can 'see' will depend on how accurate the point will be, 3D positioning needs about 8, but 2D you can get away with 4 but the accuracy will be poor.

Your mobile device will also record a home position for you, based on its view of the GPS constellation, assuming your device has GPS capability and record this in the app as your position. All being well they will co-incide, but it is possible they may be off. I have seen posts where the user reports his position being several miles from the drones HP, usually this is down to the handheld device not having GPS and resolving its position based on access to Wi-Fi, iPads do this if they are not the cellular variety.

This is why your App lady tells you 'Your home position has been recorded, please check it on the map' as a prompt to verify you are happy with the recorded point and its accuracy, its one of the last checks I do before departing, if its wrong, or inaccurate then a loss is a very likely outcome. The real important bit is that the drone is shown in the right place on the map as that's where he is going if he gets separated from your controller. You position is largely irrelevant, unless you use dynamic home position (If you're a moving target, boats and the like).

Don't forget, you can manually record a new home position in the app if you are not happy with the one captured, ultimately that is where your MP is going to go if a RTN event occurs. Its worth checking its OK before you fly off. Just record it while it hovers and acquires the image of the take off point that it will use to precision land later (Rapid flashing green 'tail light').

 

[LukasBlecha]

That "scary video" is fake.

 

[4wd]

If the original post(er) is in China or HK there's a known issue where everything is offset, that's what the China maps setting if for.

 

[Rflush]

If the original post(er) is in China or HK there's a known issue where everything is offset, that's what the China maps setting if for.

Holy ****, you are right!

To the OP, turn off Calibrate Coordinates for Mainland China and it will fix this problem.

 

[AndyT.hk]

I am sure this has been covered before, here goes anyway, GPS accuracy is dependent only many factors, including the GPS system itself & the quality of the recievers.

Your mobile device will also record a home position for you, based on its view of the GPS constellation, assuming your device has GPS capability and record this in the app as your position. All being well they will co-incide, but it is possible they may be off. I have seen posts where the user reports his position being several miles from the drones HP, usually this is down to the handheld device not having GPS and resolving its position based on access to Wi-Fi, iPads do this if they are not the cellular variety.

This is why your App lady tells you 'Your home position has been recorded, please check it on the map' as a prompt to verify you are happy with the recorded point and its accuracy, its one of the last checks I do before departing, if its wrong, or inaccurate then a loss is a very likely outcome. The real important bit is that the drone is shown in the right place on the map as that's where he is going if he gets separated from your controller. You position is largely irrelevant, unless you use dynamic home position (If you're a moving target, boats and the like).

Don't forget, you can manually record a new home position in the app if you are not happy with the one captured, ultimately that is where your MP is going to go if a RTN event occurs. Its worth checking its OK before you fly off. Just record it while it hovers and acquires the image of the take off point that it will use to precision land later (Rapid flashing green 'tail light').

Thanks guys for your thoughts but I'm not convinced of the logic.

'Your home position has been recorded, please check it on the map'

Sure, but it's wrong and that could either be GPS position or map shift. Plus I can put a Garmin GLO next to the device and that knows exactly where I am. Further I'm not sure what this China issue is; there isn't a GPS issue particularly in Chinese airspace, some airports may not use WGS84 but that's not an issue with a Mavic. I have tried various combinations of the two China settings and cannot get my RTH position to where I am. Bit dark here now, I'll try again tomorrow.

Can you tell me what App reads the txt files from the Flight Log? They don't seem to open from the DJI Go 4 App and garble when opened on a PC. I just want to see what the recorded Mavic position is cos I know what my real one is.

Cheers, Andy