JJB*
 Core User of DJI
Flight distance : 13955751 ft
Netherlands
Offline
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Hi AlxFlyMore,
Had a look at your log and video.
Flying low above water is a risk, as piloting a drone always have a sharp look out especially when software is in control of a drone (Quickshot mode).
Sensors can get confused over water reflections, bad signals ect.
Your started a Quickshot mode at :
26.2 feet baro height, 12.5 feet VPS height, distance away 36.1 feet
Quickshot ends at : 60.4 baro height, VPS height: out of range, distance 163.4 feet.
Craft flying back to begin position.
At 49.2 feet craft raises nose to reduce speed (that time approx 14 fs/s), baro height 30.5, VPS height 11.5.
At 40.2 feet speed almost zero, 4 feet from starting point and baro height 26.9.
So great returning to starting position.
My question (for DJI) is wich sensor is used for a Quickshot mode. My guess is the baro height info for flying away (plus higher) and returning back to in starting position.
If the VPS height is not used at all than it does explain why it went into the water.
I mean if you start a QS at altitude above VPS range it uses solely the baro height sensor, don`t think (not sure ofcourse) QS mode uses VPS height when within range and switching to baro height (out of VPS range) and switchin back to VPS heigt if in range again....
Baro height sensor is accurate within few feet, and changes a bit depending the flight conditions. Largest baro pressure changes are at low altitude, minor hysteresic effects on sensors are normal.
Flying back to start position QS ends at 26.2 feet, same as starting height your QS.
VPS height there 5.9 feet, so about 6 feet actual height (if sensored corerct) lower than the start, IMO all within tolerances.After ending QS the VPS height indicates 1.0, 0.7, 0.3, 0.0, drone pitched down and got some speed. Guess due to reflections of teh water starts to correct its position in P-GPS mode.
For the difference or comparison between baro height and VPS height take into account the take off position (at takeoff baro height is set to zero as reference) and the actual baro height of the sea wich is ofcourse lower. So the DJI reply about height difference is not correct.
If only you had looked at your drone all time....just pushing it up a bit on time and you had saved your MP2.
cheers
JJB
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