A lightweight, laser-based sensor system that augments an onboard autopilot with accurate altitude and attitude measurements, enabling automated landing of uncrewed aerial vehicles (UAVs).
Development status: completed system-level simulation; exp. proof-of-concept in lab (1-Hz meas rate)
The primary application would be in the original design or upgrading of UAV avionics and sensing equipment.
The sensor, composed of laser illuminators, a digital imaging unit (e.g., a camera or line scan imager), and a microcomputer, derives relative altitude and attitude from angle measurements. Below about 10 meters, the sensor's measurement accuracy is roughly proportional to the local height above terrain.
During the landing approach, a UAV requires accurate real-time (low-latency) data regarding its height above and attitude relative to the local terrain. This invention provides these measurements, enabling autopilot-controlled landing on an uninstrumented, unsurveyed planar landing strip. Removing human intervention during this hazardous phase of UAV operation will reduce the risks and increase the value of UAV operations to end users.
Single-point measurement systems can provide inaccurate altitude estimates due to local terrain slope or uncompensated attitude of the aircraft. Radar, Lidar, and other advanced altimeter systems require equipment that is complex, expensive, and heavy. This invention uses a simple arrangement of laser illuminators and a digital imaging unit to project and measure multiple points on the terrain. This provides real-time, accurate measurements of the aircraft's altitude and attitude with minimal added weight and cost.
Performance specs: operating parameters: 1 to 10 m range; plus or minus 15 degrees roll or pitch; less than 3% alt error; approx. 1 degree roll or pitch error [experimentally validated]
Radio-controlled hobby aircraft could employ this system. It may also be used for other vehicle-based distance measurement applications with a required range up to 30 meters.