This Drone Knows Where It Is Without GPS

A major challenge with any autonomous vehicle is giving it the ability to know where it is — both on the planet in general and relative to other things. That’s particularly true with drones, as wind and even minor indoor air currents will inevitably push them far off course. That’s why the LiteWing Drone Positioning Module exists and it doesn’t need GPS to do its job.

GPS has problems. On its own, it is very inaccurate. On top of that, GPS hardware is pricey, power-hungry, and weighty — all big problems for drones. GNSS helps with the accuracy issue, but not the rest. The LiteWing Drone Positioning Module doesn’t use GPS or GNSS at all and instead relies on lightweight, low-cost, and efficient sensors to help the drone track its own position.

The LiteWing Drone Positioning Module uses two sensors: an optical flow sensor and a VL53L1X ToF (time-of-flight) sensor.

A ToF sensor is a particular kind of distance sensor that works by pulsing a light (typically infrared to avoid interference) and measuring the time it takes to see a reflection. Cut that time in half and multiply it by the speed of light in that medium (air) to get a linear distance. In this case, the ToF sensor lets the drone keep track of its altitude by measuring the distance to the ground.

An optical flow sensor is what you’d find in an optical mouse. It captures images at an extremely fast rate and uses the movement of pixels in frame between images to calculate distance traveled. Here, that points at the ground so the drone can keep track of how it moves horizontally.

Put the two together and you get onboard position tracking in 3D space. The demonstration in the video is impressive and the LiteWing Drone Positioning Module seems to be very accurate within the indoor space.

Whether or not it works well outdoors at higher altitudes is yet to be seen, but this would be useful even just for indoor navigation. But this approach isn’t new for drones. The benefit here is that it is part of the open source LiteWing platform and it can be integrated into any drone.