Using image sensor and tracking filter time-to-go to avoid mid-air collisions

摘要

The present invention provides a collision avoidance system (5) for deciding whether an autonomous avoidance manoeuvre should be performed in order to avoid a mid-air collision between a host aerial vehicle (1) equipped with the system (5) and an intruding aerial vehicle. The system comprises at least one electro-optical sensor (3) for capturing consecutive images of an intruding vehicle such that the vehicle manifests itself as a target point in said images. It also comprises image processing means (7) for estimating the azimuth angle, elevation angle and a first time-to-collision estimate of the time to collision between the host vehicle and the intruding vehicle. The first time-to-collision estimate is estimated based on scale change in the target point between at least two of said consecutive images. The system (5) further comprises a tracking filter (12) which is arranged to estimate a second time-to-collision estimate using the azimuth angle, the elevation angle and the first time-to-collision estimate estimated by the image processing means (7) as input parameters. Furthermore, the system (5) comprises collision avoidance means (15) arranged to decide whether or not an avoidance manoeuvre should be performed based on any of at least one parameter, of which at least one is indicative of said second time-to-collision estimate. By using the first time-to-collision estimates from the image processing means (7) as input parameters to the tracking filter (12), the uncertainty in the second time-to-collision estimates outputted by the filter is reduced. By allowing the decision as to whether or not an avoidance manoeuvre should be performed to be based on said second time-to-collision estimates, a safe and robust collision avoidance system (5) is provided.