Abstract: A wideband direction finding (WBDF) aperture employs a limited number of extreme wideband end-fire antenna elements capable of covering a wide frequency bandwidth. Arranging variable sized antenna elements in a specific pattern, the WBDF aperture enables direction finding capability covering an extreme wide frequency band. The pattern arrangement of variable sized elements offers the signal discernment to limit ambiguities in signal angle of arrival. This small form factor design enables the WBDF aperture to be mounted on the surface of a missile, munition, or small UAS wing or fuselage. The WBDF aperture offers a combination of differing sized antenna elements arranged in a specific pattern, combined with direction finding and signal tracking to provide an unambiguous relative azimuth and elevation angle of the target.

Abstract: A wideband direction finding (WBDF) aperture employs a limited number of extreme wideband end-fire antenna elements capable of covering a wide frequency bandwidth. Arranging variable sized antenna elements in a specific pattern, the WBDF aperture enables direction finding capability covering an extreme wide frequency band. The pattern arrangement of variable sized elements offers the signal discernment to limit ambiguities in signal angle of arrival. This small form factor design enables the WBDF aperture to be mounted on the surface of a missile, munition, or small UAS wing or fuselage. The WBDF aperture offers a combination of differing sized antenna elements arranged in a specific pattern, combined with direction finding and signal tracking to provide an unambiguous relative azimuth and elevation angle of the target.

Abstract: A tracking system controls an aimed device (32) to keep it aimed at a target (34). A control system (10) determines when the tracker has lost its lock on the target (34) by comparing the target's instantaneous acceleration with its median acceleration. When the difference exceeds a predetermined threshold, the system searches backwards through a chronological buffer until it finds position data which antedate the receipt of inaccurate position data from the tracker. A second-order filter such as a Kalman filter is used to provide estimated target states. The difference between a time updated output from the second-order filter (16) and the present measured state from the tracking device is low pass filtered to provide a measurement of the instantaneous acceleration of the target. The buffer (20) stores position, velocity, and median acceleration values covering a span of time at least about twice as long as the time required to determine that a breaklock has occurred.

Abstract: A tracking system controls an aimed device (32) to keep it aimed at a target (34). A control system (10) determines when the tracker has lost its lock on the target (34) by comparing the target's instantaneous acceleration with its median acceleration. When the difference exceeds a predetermined threshold, the system searches backwards through a chronological buffer until it finds position data which antedate the receipt of inaccurate position data from the tracker. A second-order filter such as a Kalman filter is used to provide estimated target states. The difference between a time updated output from the second-order filter (16) and the present measured state from the tracking device is low pass filtered to provide a measurement of the instantaneous acceleration of the target. The buffer (20) stores position, velocity, and median acceleration values covering a span of time at least about twice as long as the time required to determine that a breaklock has occurred.