Servers by jDrones

Autonomous grid with terrain following

(wkf94025) #1

I am curious if it’s possible to use MP and ArduPlane to quickly lay out a rectangular grid (“lawnmower pattern”) for autonomous flight for geo-tagged images for feeding into Pix4D. I’m a big fan of ArduPilot and MP on fixed wing, but also a recent new fan of Phantom 3/4 and Pix4D Capture for autonomous grid mapping. It’s so easy to design and execute a mission for geo-tagged image grid, from Android phone or iPad, using a <$500 P3S. Though that whole ecosystem is fixed-altitude, and quads can’t cover the 1,200 acres I want to cover, with altitudes ranging between sea level and 400’. If I use ArduPlane and a MyTwinDream (massive endurance), can MP design a grid mission where the altitude at each photo is consistently about 120’ above local terrain?


(David) #2

Sure can. Mission planner is awesome. For elevation data mission planner uses SRTM, which is trypically accurate to around 10m. However, coverage decreases as you get closer to the poles.

In mission planner check verify height and it will reference SRTM data to calculate altitudes are each point.

(wkf94025) #3

Thanks David. Follow-on question: do I need to manually set the altitude of each point manually, or can I drag a rectangle, and tell MP to automatically set target altitude at each waypoint to be ___ m/ft above LOCAL terrain?


(David) #4


Set the default altitude to the distance you want to fly above the terrain, ensure you check verify height, create a polygon around the area of interest, and select grid. Mission planner will read the terrain elevation under each point and add your defualt to get a mission altitude. The altitudes in your flight plan should vary but maintain a constant hieght above the terrain.

(wkf94025) #5

Excellent. Thanks. Just flew a Phantom 4 Pro into a granite cliff at 35mph on Friday because DroneDeploy lacks terrain awareness, and got confused about terrain it had already flown on the previous battery. I look forward to the day when terrain awareness is a basic capability of all flight control systems.


(David) #6

Haven’t used drone deploy in quite some time. But we regularly use mapsmadeeasy. For an additional $25 bucks it will use SRTM data to keep you off the rocks. Keep in mind SRTM data is only accurate to 10m

(wkf94025) #7

Question for Mr. Oborne, or anyone else who might know the answer to this question: is it possible for me to provide elevation data to MP as an overlay on the default source (SRTM?). Reason I ask is two-fold: (1) as I get more and more into Pix4D, and map large properties repeatedly in the search for accurate elevation data, I have preliminary contour maps that are quite granular, and within a few meters of accurate in Z. I could feed one of these prelim results to MP prior to next mission, for good terrain data for terrain following during a mapping mission; (2) some of my missions are in Mexico, and I’m not sure if the default terrain elevation data there is as good as in the US.

Lack of this ability is not a show stopper, I just need to be more careful in setting waypoint elevations to try to maintain a steady AGL throughout the map footprint.

I am also about to integrate Reach RTK GPS on a MyTwinDream, and have a notion of using real time corrections to GPS position for some very tight formation flying between two RTK-enabled aircraft.


(Michael Oborne) #8

yes you can use your own elevation data in place of srtm. Currently DTED and geotiff elevation data is supported.
have a look here for more info Developer UnConference - Michael Oborne