Thanks to Andrew Maris for helping me test the auto-tracking feature of the DJI Phantom 4 Drone. Andrew was kind enough to try and “loose the drone” by sprinting underneath it. The drone did a good job not loosing him.
What is Active Tracking?
The active tracking mode is system that will allow the drone to try and follow a subject around. It allows you to select and draw a square around a moving subject on your DJI app, and the drone will “lock on” to this target and follow it around.
A couple of pointers for using the “active tracking mode”
The system is basically an image recognition algorithm. As such, it relies on good contrast and decent lighting conditions. Since Andrew was wearing a red shirt on a green soccer pitch, the system had no problems keeping track.
In other tests, where the subject is a similar color and brightness as the background, the system looses its subject much more often. And of course if the subject is briefly obscured (by a tree, or under a bridge), or even when another similar looking subject passes through the frame in close proximity, the system gets confused.
Also, in order for the drone to track optimally, you need to allow it to fly backwards, a setting you can adjust in the DJI app. This means object collision avoidance will work only while it is moving forward, and therefore it’s more risky as the drone can easily “back into” obstructions, causing a potential crash. So the auto-track mode is best done in an open area.
Also, the does not accommodate altitude changes, so if you are running up a hill, the Phantom will not adjust it’s altitude along with you.
Altitude and subject movement speed matters as well, if you are trying to auto-track a fast moving subject at 10 feet, it will move through the visual frame more quickly than when the drone is at 25 feet, and therefore tracking performance is better at a slightly higher altitude. However, go too high and the subject will be relatively small in the overall frame, and the visual tracking system cannot always keep up.
Tracking Alternatives Using Autoflight Logic’s “Follow Mode”
If tracking a moving subject up and down a terrain is required, there is an alternative outside the native DJI app. More advanced flight modes can be configured in Autoflight Logic, and these are not based on optical tracking, but on tracking a paired and GPS connected iPhone running the Autoflight Logic app in what they call a “connected airspace”. Here is a brief tutorial: