Comparing Precision of Autopilots for Survey Missions - DJI Phantom 4


Here at SPH Engineering we have a fleet of various drones we use for diverse research and development projects as well as testing new releases of UgCS.

When it comes to using drones for land surveying, mapping or 3D reconstructions, flight precision plays an important role. This is why we decided to test the precision of different drones to see how well they compare to one another. For that we prepared a short photogrammetry mission in UgCS to see how well does the actual flight trajectory correspond to survey lines.

In the first part we tested the DJI Phantom 4 using different turn types: first flight with Stop and Turn, second - Adaptive Bank. See the flight comparison in the video below:


 

We will try and publish one drone test per week. Next-up will be the DJI Naza-M V2.

Below are the KML files from the test route and the flight paths. You can import and view them in Google Earth.

Test Route
Phantom 4 Adaptive Bank Turn
Phantom 4 Stop and Turn

Get the newest version of UgCS here: www.ugcs.com


Safe flights,
UgCS Team




Views: 754

Comment by Marc Dornan on March 17, 2017 at 11:04am

Well a Phantom 4 must be better than a Naza M V2. How about a Pixhawk 1/2 with a high quality M8 GPS and latest Arducopter?

Comment by Alexey Dobrovolskiy on March 19, 2017 at 3:40am

Phantom 4 is much better than Naza. We already did that test and were surprised by results...

We will test almost all our fleet, we have in operational condition at the moment:

- Mikrokopter Quadro XL
- Microdrones MD4-200
- Kestrel Indago 

- 3DR Pixhawk (Arducopter)

- DJI Naza-M V2 
- DJI WooKong-M
- DJI A2 
- DJI Phantom 3 Pro 
- DJI Inspire 
- DJI Phantom 3 Standard
- DJI Phantom 2
- DJI Phantom 4
- 3DR Iris (PX4)
- 3DR Iris (ArduCopter)
- DJI A3 
- 3DR Pixhawk with RTKite RTK board
- Drotek Dropix on same frame as original 3DR Pixhawk - it will be interesting to see difference between two autopilots with same software (ArduCopter - we should use same version)
- Micropilot MP2128

Comment by Mark Fink on April 6, 2017 at 5:57am

Is the Phantom 4 (Pro?) able to take pictures faster than the Inspire 1 Pro? The Inspire is limited by the SDK, (thanks for providing that information on another post), to one frame every five seconds. If the Phantom 4 can shoot at a faster rate, then it should be able to fly missions at a faster rate as well. 

If I recall correctly, the Inspire 1 Pro doesn't allow for adaptive banked turns, which also slows missions down considerably. Don't get me wrong, I really like the image quality of my Inspire 1 Pro, but maybe it's not the right tool for photogrammetry.

Mark

Comment by Alexey Dobrovolskiy on April 7, 2017 at 4:03am

Hi Mark, according specs Phantom 4 Pro can make still photos with 2s interval (http://www.dji.com/phantom-4-pro/info#specs).

Inspire supports adaptive bank turns but it will miss part of waypoints and camera actions in these waypoints will not be triggered.

If you need to fly quick your photogrammetry area I recommend you to set camera by time action at beginning of your photogrammetry grid.

Comment by Mark Fink on April 7, 2017 at 6:45am

Hi Alexey,

I'll do some testing today with adaptive bank turns. If it is just missing the waypoints at the end of each leg of the route, I can adjust by pushing the waypoints out just a little farther so I have enough coverage.

I had tried the camera by time action, but it is still limited to one photo per five seconds. Setting this to a faster rate drops frames. Unless UGCS has been updated to allow this outside of the DJI SDK limitations. That would be great!

Comment by Alexey Dobrovolskiy on April 12, 2017 at 2:52pm

Hi Mark,

you can use overshot parameter in Photogrammetry tool. In our test we used 20m overshot but it seems that 10m will be enough.

Regarding frame rate - it's not SDK or UgCS limitation. It's camera's own limit. It needs time to save megatons of data from the sensor...

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