At a foundational level, autonomous flight requires reliable and efficient obstacle avoidance. On resource constrained systems like drones, that can often mean a tradeoff between capability and weight. For many platform builders, finding a low SWaP and powerful solution could come with compromises.
Ascend Engineering collaborated with Sony Electronics to eliminate the need for compromises by doing the integration work to make Sony’s AS-DT1 into a first-class citizen in the PX4 Autopilot ecosystem. The Sony AS-DT1 is the smallest and lightest 3D LiDAR sensor in its class. It includes a SPAD-based direct Time-of-Flight module that weighs about 46 grams, ranges up to 40 meters, and holds ±5 cm accuracy even on low-reflectivity targets in full daylight.
Ascend wrote the sony_asdt1 driver and upstreamed it to PX4, connecting the sensor to the flight controller over a standard serial port. That means no companion computer is required. The driver publishes the sensor’s 576-point depth grid directly into PX4’s obstacle_avoidance topic, piping it into the PX4’s collision prevention system directly. This is a huge win for open source obstacle avoidance. 
The integration will feel almost native to PX4. All five of the sensor's range modes, covering 20,30, and 40 meter configurations, different frame rates, and point densities, are configurable. Setup is stress free as users just have to enable the driver in the board configuration, assign a serial port, and reboot. The driver handles the rest.
“It’s exciting to be able to bring the Sony AS-DT1 to the PX4 ecosystem and make quality obstacle avoidance easily available to builders making commercial-grade products on top of open source,” said Andrew Brahim, Principle Engineer at Ascend Engineering who led the project. “Obstacle avoidance should not be hard and it was a pleasure working with Sony to make it that much easier.”
The majority of work on the driver was conducted by Sean Hickey, Software Engineer at Ascend Engineering, and upstreamed to the distance sensors section PX4 Github repo. For those interested in integrating the AS-DT1 themselves, you can find both the sensor information, and the driver reference in the PX4 docs.
For more information on the AS-DT1 LiDAR Depth Sensor visit Sony’s website here.