Sense and Avoid Sensor Selection

Hi Everyone!

For this week's research assignment, I chose the DJI Phantom 4 to discuss its sensor suite for collision avoidance technology.

I chose this small UAV because it is considered the leader in commercial UAVs for aerial photography and video.  It's flagship model, the Phantom 4, was recently released for the mass market in Spring 2016 and it contains small improvements on speed and battery life over its predecessor but primarily boasts its novel sense and avoid system which separates it from the rest of its rival small UAVs.

DJI Phantom 4

The DJI Phantom 4 costs approximately $1399 USD.  Its take-off weight is 1380g, travels a max speed of 20 m/s, operates at a maximum ceiling of 6,000 metres and can last for up to 28 minutes of flight.  The Phantom 4 is powered on a single LiPo4S battery with 5350 mAh capacity and takes approximately 1 hour for a full charge at maximum power of 100W.

Dual Under-Carriage Sensors

The sense and avoid system have a range of up to 50 metres and has 60 degrees of viewing angle. It has two forward facing optical cameras and two sonar and optical cameras underneath for ground detection.  The minimum separation distance between obstacles is programmed at around 2 metres, so any intentional or accidental collision courses would be prevented.  The main limitation of this small UAV sensor system is the lack of overhead sensors and rear facing sensors.

Dual Forward Facing Sensors

The technical process that governs the entire sense and avoid system is focused around its flight controller which acts as the brain to compute and analyze all of the inputs gathered from its front and under-carriage sensors.  The computer algorithm calculates incorrect data and invalidates it to determine obstacles, then cross-references it with its positional data gathered by its proprioceptive sensors such as its dual INUs for inertial status and its barometer for altitude reading.  The GPS also acts to determine its position relative to its environmental settings and the flight controller outputs the requisite manipulations to coordinate adjustments to its 4 motors, resulting in a mid-air side-stepping of any potential obstacles.

Phantom 4 Sense and Avoid Path

Although expensive, this compact sUAS is the leader in aerial photography drones currently available in the market.  It is a leader in sense and avoid technology and boasts the follow-me function without the operator having to carry and transponder device.  It is a great asset whose collision avoidance technology could be leveraged for other unmanned systems.