A vision based sense and avoid system for small unmanned helicopter

Sense and Avoid (SAA) has been identified as one of the crucial technologies for integrating UAV into civil airspace, and vision based SAA is regarded as a promising solution. In this paper we described our vision based SAA system consisted of onboard vision detection system and Groud Control Station (GCS) to fulfill the intruder detection and avoid maneuver control tasks. To realize the small intruder detection in collision scenario, we adopt a CMO filter based method for pre-processing as well as a HMM filter for target detection. The adopted algorithms are modified and immigrated on a high performance DM8168 onboard computer for efficiency consideration. Due to the depth missing problem of vision sensor, we developed a relative angle based avoidance strategy to perform the collision avoid of intruders. In the end, the proposed system is tested on real flight scenario to demonstrate its capability for small intruder collision avoid.