Probably a stupid question about height but here goes.....

[Meta4]

perhaps the settings for our drones for use in the UK are different to yours in the USA but if i try to alter the max height in the app with it all connected up as you say then it just reverts back to 120 mtrs

No, it's the same all over the world.
It's not a UK thing and it's not a legislative thing.
Have your drone connected and you can adjust the MAX Altitude Limit all the way up to 500 metres.

 

[old man mavic]

No, it's the same all over the world.
It's not a UK thing and it's not a legislative thing.
Have your drone connected and you can adjust the MAX Altitude Limit all the way up to 500 metres.

I just tried it and yes you are correct this stupid old man mavic didn't realise that he had to touch the up arrow on his screen after changing the setting lesson learned thanks for your help and advice we learn something every day and I am not to proud to admit when I have got it wrong

 

[tcope]

Another reason to turn off VPS over water: position stability prefers VPS over GPS, and may see moving waves/ripples as stationary patterns. This may cause the quad to drift some with the current. However when it then sees GPS drift, it tries to counter correct it's position.

That is not correct. GPS always trumps either VPS.





I've tested it, if you have a GPS signal the downward Vision System does nothing. I've also tested altitude control and after the Phantom 3, VPS does not change altitude when not in Active Track mode.

 

[tcope]

It has been advised to turn the sensors off when flying low over water as it will not always read the height accurately.

That is a throwback to the P3, when downward sensors controlled the altitude (even then, it was questionable). The downward sensors on the P4 and Mavics no longer control/adjust altitude unless in Active Track mode.

 

[DanMan32]

That is not correct. GPS always trumps either VPS.

View attachment 63483

View attachment 63484

I've tested it, if you have a GPS signal the downward Vision System does nothing. I've also tested altitude control and after the Phantom 3, VPS does not change altitude when not in Active Track mode.

I suggest trying VPS over a treadmill with distinguishable markings on the track.
Or fly 5-10' over a rug outdoors and slowly pull the rug.
Your first exhibit actually tends to support my statement as it focuses on VPS even with GPS. Your 2nd one is inapplicable since it focuses on GPS loss.
Really it doesn't really make it clear either way, only that it's best used indoors where you're likely to not have good GPS.

 

[DanMan32]

That is a throwback to the P3, when downward sensors controlled the altitude (even then, it was questionable). The downward sensors on the P4 and Mavics no longer control/adjust altitude unless in Active Track mode.

Actually at very low distance to ground, such as 2" out a ground gently sloping up, it does. I discovered that going across my front lawn from my house to the street.
I thought that might have been implied terrain mode, but it only works very low to the ground, and only up, not down.

Also note when you are in VPS range, you get two altitudes: one based on barometer, other based on, depending on model, ultrasonic or IR sensors.

 

[tcope]

Or fly 5-10' over a rug outdoors and slowly pull the rug.

Have done it. Flannel blanket with large lines all across it. Hovered the drone and pulled the blanket around. Drone never moved.

Your first exhibit actually tends to support my statement as it focuses on VPS even with GPS.

It mentiones that VPS helps maintain stability indoors (no GPS) and even when GPS is not available (no GPS). So VPS takes over when conditions are such that there is no GPS.

Your 2nd one is inapplicable since it focuses on GPS loss.

It is actually spot on for that reason. As I mentioned, VSP does not override GPS. So VPS only works when there is no GPS.

 

[tcope]

Actually at very low distance to ground, such as 2" out a ground gently sloping up, it does. I discovered that going across my front lawn from my house to the street.

What you are actually seeing is the forward sensor avoiding the ground. So yes... at something around 2" the forward sensors will move the drone upward instead of stopping it. Any higher (and faster than a slow crawl) and the drone will stop. But again. this is a function of the forward sensors.[/QUOTE]

 

[jagraphics]

Not at all.
That would only be true if the earth is pancake-flat (and it isn't).

Oh yes it is. I have seen the videos on Youtube and the earth is a flat disk......
They have proof and everything!





Must get the Flat Earthers to fund me on an expedition to get some drone footage of the edge of the disk.

 

[Tom2770]

The max altitude limit is 500 meters. You can increase it above the default 400 feet in DJI GO.

Yes, the Mavics can go to 500 meters (1642 ft). However, the FAA has us limited to 121 meters (400 ft) higher than the point the AC was launched from.

 

[Congoblue]

Yes, the Mavics can go to 500 meters (1642 ft). However, the FAA has us limited to 121 meters (400 ft) higher than the point the AC was launched from.

No, the FAA (and CAA in the UK where I am) say it's 400ft above ground level at the drone's position, which may not be the same thing if you are standing on the side of a mountain.

 

[Meta4]

Yes, the Mavics can go to 500 meters (1642 ft). However, the FAA has us limited to 121 meters (400 ft) higher than the point the AC was launched from.

Height above launch point is irrelevant.
No country in the world has rules about height from launch point.
Consider this scenario .. two drones flying a few metres apart:

By your reasoning, one of those drones is in breach of regulations.
How can that be when they are essentially in the same place?

 

[urikita]

The height mentioned in the picture GPS properties is above see lever, right?
Is there a way to know the height above home-point of each picture after the shot has been taken?

Thank you !

 

[Jackcutrone]

Indeed it is height AGL for the FAA regs. Different concept than DJI’s limits though that is an attempt by DJI to accommodate the FAA regs

 

[inno]

The height mentioned in the picture GPS properties is above see lever, right?
Is there a way to know the height above home-point of each picture after the shot has been taken?

Thank you !

yes, if you use airdata or can access your flight logs by some other means it will show height above home point as well as sea level

answer to your first question, sorry. not sure. never questioned or need that number. but again check out the log file just match it to home point or sea level.

safe flying!

 

[old man mavic]

Height above launch point is irrelevant.
No country in the world has rules about height from launch point.
Consider this scenario .. two drones flying a few metres apart:

By your reasoning, one of those drones is in breach of regulations.
How can that be when they are essentially in the same place?

a question for you Meta4 as we all know 400 ft AGL is the important measurement when flying our UAV and i know that if i was pilot (A) in your picture and was at 100 ft and i then flew out to where Pilot (B) was standing i would then be more than 400 ft AGL my question is how would i know from the height info shown on the GO4 app screen,that i was at 500 ft above AGL would the height change as i flew out to reflect this change i am aware that if you drop down lower than your initial take off point then a negative height is shown on the screen but that does not really tell me my AGL height

 

[Meta4]

a question for you Meta4 as we all know 400 ft AGL is the important measurement when flying our UAV and i know that if i was pilot (A) in your picture and was at 100 ft and i then flew out to where Pilot (B) was standing i would then be more than 400 ft AGL my question is how would i know from the height info shown on the GO4 app screen,that i was at 500 ft above AGL would the height change as i flew out to reflect this change i am aware that if you drop down lower than your initial take off point then a negative height is shown on the screen but that does not really tell me my AGL height

That's just one of the many things you just have to use common sense for.
If you were flying a Cessna, you probably wouldn't have a radar altimeter and would have the same problem.
The plane pilot would look at his charts, do some mental arithmetic, estimate by eye etc.

In your case, if you are close to the hill, it's not a big issue as real aircraft aren't going to be flying there.
If you were to fly far out, estimating would be one way or planning by checking heights in Google Earth so you knew how far to descend to maintain a safe altitude.

 

[MichiganMavic]

Height above launch point is irrelevant.
No country in the world has rules about height from launch point.
Consider this scenario .. two drones flying a few metres apart:

By your reasoning, one of those drones is in breach of regulations.
How can that be when they are essentially in the same place?

I had this scenario in Maui when I was flying from sea level and followed the terrain up the side of a mountain. The Mavic reached 1643’ and the “ Reached Maximum Height” read on top of my screen.
That sucked because I was following the grade approximately 25’ above.

 

[virasMavic]

then if you are in the uk it is set to 120 meters in the app around 396 ft this is the max you can fly in the uk under the present rules and it will not go any higher it is geofenced at that height.if you take it up you will see it stop when the max height is reached that height is from where you are standing.when you launched as you correctly said but if you had taken off from a cliff top or high point overlooking a valley then as you flew out from your take off point you would have to descend to keep 400 ft AGL

This is the most accurate description of the Max Altitude flying limit. A graph also, should be quite helpful to those who have some misunderstanding!!! Congratulations!!!!

 

[old man mavic]

That's just one of the many things you just have to use common sense for.
If you were flying a Cessna, you probably wouldn't have a radar altimeter and would have the same problem.
The plane pilot would look at his charts, do some mental arithmetic, estimate by eye etc.

In your case, if you are close to the hill, it's not a big issue as real aircraft aren't going to be flying there.
If you were to fly far out, estimating would be one way or planning by checking heights in Google Earth so you knew how far to descend to maintain a safe altitude.

thats what i thought so really the height shown on the app is not of much use. just one more point, when the flight logs are saved to the cloud do those logs show the real height that the mav was flown at during a particular flight with relation to the ground or is it only the height above the take off point i only ask because could those flight logs be used to prosecute you if you were accused of flying above 400 AGL at some point during your flight