Abstract: A horizontal miss distance filter system (220) is provided for inhibiting resolution alert messages from an air traffic alert and collision avoidance system (210) to a pilot's display (230). The horizontal miss distance filter employs a parabolic range tracker (10) to derive a range acceleration estimate (11) utilized to discriminate intruder aircraft (110) having non-zero horizontal miss distances. The horizontal miss distance calculated from the range data provided by the parabolic range tracker is compared with a bearing based horizontal miss distance provided by a bearing based tracker (22). The smaller of the two calculated horizontal miss distances defines a projected horizontal miss distance which is compared with a threshold value. Any resolution alert for intruder aircraft whose projected horizontal miss distance is greater than the threshold will be inhibited unless it is determined that the encounter involves a maneuver of one of the aircraft.

Abstract: A technique is disclosed for multiple sensor tracking which distributes data association and filtering processing among multiple processing entities but coordinates the track estimates such that track states and covariances represent the equivalent of a centralized estimate. The object of the invention is to establish and maintain a single system track for a single aircraft in a distributed processing environment. This is achieved through communication of track information among processing entities which process a single sensor's inputs. Continued updating and re-broadcasting of process data are performed between the multiple sensor's processing entities.

Abstract: A laser-based target discriminator system for discriminating desired objects from other objects and clutter in an image scene is disclosed. The system is operative to scan a pulsed laser beam a plurality of times across an image area, the scans covering different juxtaposed strip portions of the image area. Range differential signals are derived from the sensed information of successive laser pulsed echoes of each scan corresponding to the image elements thereof. From the range differential signalling, a binary image map of the image area is generated and converted into a second topological image map having index codes which are derived from predetermined groupings of the binary values of the first image map. Clusters of contiguous image elements are identified from the second image map based on the derived codes of the indices thereof. Desired clusters may be discriminated from the identified clusters based on measured predefined parameters thereof.