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Two more Mavic Air questions

Music One

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Thanks for all the info on my other post about the Homepoint. Firstly re that again, I went out twice flying yesterday and on both occasion the controller spoke to me saying Home Point updated and I hadnt touched anything. It showed my position on the map spot on. Can that happen. And my second question, which sounds silly but its just for my info. Living near hills & mountains there are unlimited places for me to go off and practice with the camera etc. If I took off on the top of a hill and then flew out into the valley, how does the mavic air decide how high it is, when the ground suddenly appears hundreds of feet below and I have a max altitude setting off say 150ft. Hope that makes sense. Any, sorry for so many questions.
 
Thanks for all the info on my other post about the Homepoint. Firstly re that again, I went out twice flying yesterday and on both occasion the controller spoke to me saying Home Point updated and I hadnt touched anything. It showed my position on the map spot on. Can that happen. And my second question, which sounds silly but its just for my info. Living near hills & mountains there are unlimited places for me to go off and practice with the camera etc. If I took off on the top of a hill and then flew out into the valley, how does the mavic air decide how high it is, when the ground suddenly appears hundreds of feet below and I have a max altitude setting off say 150ft. Hope that makes sense. Any, sorry for so many questions.

The sounds is actually coming from your mobile device and it’s just letting you know that it has locked it current gps position and is now using that as the home point. I doesn’t always announce it especially if flying multiple batteries using the same home point.

The Mavic Air uses its barometer and GPS location information to determine its altitude from the home point. That’s actually what it’s showing you as the “height” in the app and that’s what the RTH height is also based on. It’s not based on distance to the ground as the Mavic can’t measure that more than 30m above ground.

Now if the aircraft is within 30m of ground it will show the height above ground as measured by the bottom sensors in the app but that is for your reference only and separate from the main “height” it shows which is just the height above the home point.

I was flying in the mountains this weekend and was at the top of a canyon. I took off
 
Thanks for all the info on my other post about the Homepoint. Firstly re that again, I went out twice flying yesterday and on both occasion the controller spoke to me saying Home Point updated and I hadnt touched anything. It showed my position on the map spot on. Can that happen.
Home Point Updated is different from Home Point Recorded.
It means that GPS was not 5/5 when the HP was recorded and the drone has updated the HP when it got better GPS quality.
And my second question, which sounds silly but its just for my info. Living near hills & mountains there are unlimited places for me to go off and practice with the camera etc. If I took off on the top of a hill and then flew out into the valley, how does the mavic air decide how high it is, when the ground suddenly appears hundreds of feet below and I have a max altitude setting off say 150ft. Hope that makes sense. Any, sorry for so many questions.
Your drone won't know that the ground is hundreds of feet below (because it has no sensors that can detect thet).
It will only know it's height relative to the launch point.
And it won't matter because it's a flying machine - not a stay-close-to-the-ground machine.
 
ps ... the VPS sensors have a range of 10 metres - not 30 metres as mentioned earlier.
 
ps ... the VPS sensors have a range of 10 metres - not 30 metres as mentioned earlier.
Negative. The aircraft is only able to use downward vision position to hold its position up to 8m. However, it’s actually able to detect objects below it up to 30m. Remember the ultrasonic sensor is down there too. 73165
 
I went out twice flying yesterday and on both occasion the controller spoke to me saying Home Point updated and I hadnt touched anything
Assuming the GPS signal strength is good at the beginning of the flight (the ideal scenario), the home point will be marked when you start the motors. When that happens, the DJI GO app usually announces it and you'll see an "H" symbol in the location where the home point was marked. After that point, the home point should not move unless you manually reset it.

If you believe the home point was automatically reset, then your TXT flight log should explain what happened. You can upload and view that flight log online here.

Living near hills & mountains there are unlimited places for me to go off and practice with the camera etc. If I took off on the top of a hill and then flew out into the valley, how does the mavic air decide how high it is, when the ground suddenly appears hundreds of feet below and I have a max altitude setting off say 150ft.
When the aircraft is sitting on the ground at the takeoff point, the altitude will show 0 feet at the bottom of DJI GO. When you fly above that point, the altitude will increase and display a positive number. When you fly below that point, the altitude will decrease and show a negative number.

If you fly 50 feet below the takeoff point into the valley (for example), the altitude would show around -50 feet at the bottom of DJI GO. In order to hit the max altitude of 150 feet from that location, you'd need to ascend 50 feet to get up to 0 feet and then ascend another 150 feet to get to the max altitude.
 
Negative. The aircraft is only able to use downward vision position to hold its position up to 8m. However, it’s actually able to detect objects below it up to 30m. Remember the ultrasonic sensor is down there too.
So it can measure distance to the ground to the grand total of 8 metres (rather than 10 metres like most other DJI drones).
 
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