jivago Posted at 4-29 04:53
This problem happens when start point of mission is far away from take off point and its height was less than take off point. Therefore mission planing software decides not to go high enough to reach flight height.

Maybe it's for saving power or mistake of programmers!

I have just purchased the P4 RTK and have worked through how to add a DSM and fly Terrain-aware missions. I am flying highly forested and hilly terrain and many of my missions are multi-battery. On my third terrain-aware mission, the first waypoint of the second-battery flight was lower than my takeoff location. The set height was 80 m, but the drone only took off to 65 m. Fortunately obstacle avoidance kicked in and the drone stopped before hitting the tree it was ready to hit. Since this was my fist time experiencing this, I did not expect the drone to fly below 80 meters. For my P3 drones, I always used Maps Made Easy Map Pilot for DJI software and never had this issue before.

This is a very serious application/programming error! If I would have lost my drone because of this issue, I would insist that DJI fully replace the drone.

Has DJI offered any feedback, response, or explanation on this issue? Has anyone damaged or totaled their drone as a result of this issue? This seems like an overtly easy problem to solve and it should have been solved long ago or not been a problem in the first place when the GS RTK App was released with terrain-awareness.

Hi
Your are completely right , but till now, DJI hasn't released any update for fixing this bug.

jivago Posted at 7-11 04:10
Hi
Your are completely right , but till now, DJI hasn't released any update for fixing this bug.

Have any one experienced issues due to the resolution of the DSM? Would you recommend using only a coarse-res DSM (e.g. SRTM)?

xabierr,

I am a fan of lower res DSMs to manage battery life and flight time. I keep it off the rocks and get a fairly consistent height above the ground.   

xabierr Posted at 7-15 22:43
Have any one experienced issues due to the resolution of the DSM? Would you recommend using only a coarse-res DSM (e.g. SRTM)?

I use low resolution DSM and have seen no issue on that.

Good morning everyone.
Sorry if the wording of this text is not quite right.
I'm using google translator.
The DSM generated by a previous P4RTK flight can now be used.
My workflow of is as follows:
1. Make an inspection flight at 180 to 250 meters to generate in the DSM in Metashape.
2. Then I export this DEM with Global Mapper with a resolution of 1 m or 5 m according to the variability of the terrain that my study area presents. (I generate my DSM in WGS84 along with prj, tfw files)
3. Then I upload it as usual and do the Terrain Awareness Filght flight mode.

* The flight height is adequate, when changing the battery it is positioned at the same height at which the first flight ended.

RenzoTM Posted at 8-24 20:51
Good morning everyone.
Sorry if the wording of this text is not quite right.
I'm using google translator.

RenzoTM,

Workflow looks good. Just remember to use ellipsoidal instead of orthometric height for the file uploaded to the RTK controller.

Skyveyor112 Posted at 8-26 03:17
RenzoTM,

Workflow looks good. Just remember to use ellipsoidal instead of orthometric height for the file uploaded to the RTK controller.

And as noted, lower XY resolution can be desirable in some cases, especially for larger areas.
(And don't fly at that AGL in the USA w/o a waiver!   )

patiam Posted at 8-26 15:10
And as noted, lower XY resolution can be desirable in some cases, especially for larger areas.
(And don't fly at that AGL in the USA w/o a waiver!   )

Hi
Maybe someone will find this link useful.
Quickly generate DSM with ellipsoidal heights.

https://portal.opentopography.or ... TSRTM.082016.4326.1

GEORobson Posted at 10-28 12:00
Hi
Maybe someone will find this link useful.
Quickly generate DSM with ellipsoidal heights.

Nice resource!

AntDX316 Posted at 2020-6-11 22:45
Can't you just manually fly at the target altitude then resume mission?

sure. once you know of this bug its not a problem. The problem is that unless you read this forum there is no way to know about this bug, except finding it out by yourself in the field.

I did a mission where the resuming point after battery change was lower than my take off. The drone lifted only 1 meter and then proceeded to go to the waypoint., it missed my car and a building just by luck. There was no time to react and take over manual control.

Yes, this error is unacceptable. In https://forum.dji.com/forum.php?mod=viewthread&tid=241299 I am asking if there will be any other firmware update for the P4R and the D-RTK 2 to solve this and many other serious problems.

Phantom 4 RTK receives the wrong terrain when flying in shape
In the present time, almost most of the 4 rtk phantom drones when flying over the terrain according to the PPK method receive a lower altitude than the set value.  At first I thought due to wrong DSM but I tried many ways but same result.  I tried updating to the latest version for both the plane and the controller but the result is still the same.  Does anyone have a solution to this problem?  Thank you very much
P/s:
I've been cruising for over 2 years using the PPK method and it's been great. But recently, suddenly, the plane didn't fly the way it used to. However when same altitude or using DBase the plane is stable
I think the Chinese satellite has corrected the signal to cause such an incident.
Fly to 1 altitude or use DBase no problem=>
- Flying in 1 altitude, it receives the ground altitude at the take-off position
- Using DBase, it's always rectified for the plane, so it doesn't affect.
Looking forward to a solution