After trying 3 different Iphone models, 4 different drones... I figured out It's the DJI GO 4 app. It won't update to mobile device home-point if the accuracy of certain phones are reporting more than 15ft inaccuracy. DJI GO 4 app won't allow to update, Stating GPS Signal too Weak to update Current mobile Position, even though your gps signal on the phone may be spot on, if the phone GPS Module doesn't report within a certain perimeters that was set by DJI in the programming of the GO 4  app, then it won't let you use your dynamic home-point. Doesn't work in Active track either when when dynamic position is set on and  you go beyond the 180ft limit of aircraft take off point. The drone will stop in the air. I've reported this very issue several times dating back a year ago. All they have to do is allow the drone to update mobile home point gps location even when the newer Iphones are reporting a inaccuracy of 5 meters or more, although its not actually true. I know Iphone X works fine and the new Iphone XR, Test your phone GPS Accuracy and Download a gps accuracy app and see if your phone can come within 12ft of reported gps accuracy, if not, until DJI updates there firmware to include these perimeters, we are all out of luck. My friend has the Iphone X and it doesn't do it with his, I had the Iphone 6s, the 8plus and now I have the XS MAX and every phone I have had, has this issue, even with 4 different drones. Only way to fix, is to have another mapping app open and toggle back and forth between the Go4 app and the google map, Maps or Here Maps and let it refresh your position. Then switch back to GO4 and click on the Person Icon in the settings to update mobile position. Then home point will be updated...But it will only do it for a minute or so at a time, then you have to toggle back and forth again and again and  keep refreshing your maps app to allow your position to refresh.  It fucking sucks. Especially if you want your drone to follow you while your riding a bike or moving and cannot continually keep stopping and keep toggling back and forth between the apps so that your damn drone can keep following you in active track after you go beyond 180ft from last updated position. Havent tested it yet on the Follow me mode. Hope this helps, and if someone can get through to DJI, Let them know that many many many people are having issues with this. I did everthing to figure it out, almost a year now, this is the best solution. And DJI, quit asking everyone if they have there damn location turned on in the IOS settings. ITS NOT THAT! GET IT FIXED!!

I tested it today, it will work also when you just have a gps accuracy app open that is pulling in a fresh coordinate, but with that said, you still have to toggle out of DJI Go4 app, switch to the gps app and then back to the DJI GO4 app. Somehow this is refreshing the DJI GO4 app accuracy good enough to be able to set the new home point location mobile device. I'm trying to figure out a way to have a app running constantly thats receiving a new update of ordinates that automatically refreshes dji GO4. I even have a apple watch series 4 and was seeing if running a app on the watch would help refresh the mobile device, but apple doesn't allow the iphone to use the watch gps as a so called Bluetooth GPS Receiver. So I'm just going to get a cheap android Tablet and fly with that until DJI gets there heads out of eachothers asses.

That is definitely DJI solution for mountain bicycles. As far as I know, you can easily found some alternatives for such equipment over the internet. On that purpose you can visit some kind of reviews at specialized blogs like Bestadviser (<a href>http://bestadviser.net/reviews/mountain-bikes-reviews/top-mountain-bikes-helmets-and-clothing-review/</a> ) for example. Of course, I can't guarantee that the quality will be the same, but anyway you will spend less money, don't know what decision is right, that is up to you.

Jasette Posted at 4-3 12:55
That is definitely DJI solution for mountain bicycles. As far as I know, you can easily found some alternatives for such equipment over the internet. On that purpose you can visit some kind of reviews at specialized blogs like Bestadviser (<a href>http://bestadviser.net/reviews/mountain-bikes-reviews/top-mountain-bikes-helmets-and-clothing-review/</a> ) for example. Of course, I can't guarantee that the quality will be the same, but anyway you will spend less money, don't know what decision is right, that is up to you.

I just ordered a Huawei Mediapad T3 8" for $99 from Amazon. Did a lot of research before ordering this tablet, 80% of people who used this aporoves it for flying with mavic pro. I hate having to use Android device since i spent $1,199 on a iPhone XS Max that i thought for sure wouldn't have any issues with dji go4 weak gps signal issue. Thanks Dji for making me have to buy another product because you can't figure your ... out. You owe me $100.

Aaron Rupp Posted at 2019-4-3 20:50
I just ordered a Huawei Mediapad T3 8" for $99 from Amazon. Did a lot of research before ordering this tablet, 80% of people who used this aporoves it for flying with mavic pro. I hate having to use Android device since i spent $1,199 on a iPhone XS Max that i thought for sure wouldn't have any issues with dji go4 weak gps signal issue. Thanks Dji for making me have to buy another product because you can't figure your ... out. You owe me $100.

Did you ever get this resolved?  I have the Mavic Pro and iPhone Xs Max - having the exact same issue with Dynamic Home Point - says GPS signal is too weak?  Got this video this weekend:

https://drive.google.com/open?id=1q7Czpn7EHx1FwiR_tlkrwdkHp3fo56_u

Activer Track is supper cool - but it just stops when we hit the range from original start point

I can confirm too I have the very same issue with DJI Go 3 on iOS with an P3P. I've searched back in my flights history, and found that all flights up to April 9th 2019 still had the RC GPS position, then on my next flight from April 25th 2019 until the present day, the RC GPS position didn't appear anymore on the map.
If you guys report that all works fine on Android, then it's just an iOS bug, isn't it ? Why woudn't it be solved ?

LE: the trick with Google Maps app running in background and a flip-flop back'n'forth to it, doesn't bring to me the RC GPS position on the map.

Hopes & dissapointments...
Following my complaint in the above post, in a time frame of 1 hr a strange but positive event happened, the tablet has started to show again its gps position as a lighblue dot on the DJI Go 3 app map.

Today I had the opportunity to fly and check the new behaviour.
Unfortunately the tablet gps position is not recorded as RC position, when trying to establish the tablet position as the AC home point position, the system returns the same warnings "Mobile Device GPS Signal Weak. It's location cannot be acquired." & "Home Point not recorded."

More, the gps position is remaining on the DJI Go map just for my iPhone and iPad Air 2, both devices having iOS 13.5.1.
On my older tablet iPad mini 2 (that I'm using since years to fly the drone, but it cannot be updated further than iOS 12.4.7), the lightblue dot dissapears in 1-2 seconds after the usb cable is connected to the device.

So the issue is still unsolved for iOS users...

When your GPS Signal Not Found, first you must try to restart your device and then check if it solved your issue or not.
If not, then try some troubleshooting methods in the below mentioned post to get rid of this problem: https://recover-androiddata.com/pokemon-go-gps-signal-not-found-android/

Quest-So Posted at 2020-7-20 06:48
Hopes & dissapointments...
Following my complaint in the above post, in a time frame of 1 hr a strange but positive event happened, the tablet has started to show again its gps position as a lighblue dot on the DJI Go 3 app map.

Indeed, it is still a problem with DJI Mavic 2 Pro and iPhone 7 as well as with iPhone 11.
No chance to set Home point to Me.
I noticed this problem about a year ago, there was no rush at that time, but now it becomes an issue as I need this functionality.
I paid for something which is not working.

After trying so many things eventually got rid of the issue by granting location access to the maps app. https://thegeekpage.com/how-to-fix-gps-not-working-on-iphone/