Abstract: A proximity radar is described in which a signal phase modulated in accordance with a pseudorandom sequence is transmitted from an antenna, and a return signal reflected from a target is received by this antenna. The return signal is correlated with a signal identical to the transmitted signal but delayed by a selected time interval. The delay imposed on the transmitted signal as fed to the correlator is alternately given the two values n.t and n'.t where n' is less than n and the time interval n.t corresponds to the time taken by the signal to travel to and return from the target when the radar is at a predetermined distance from the target, which distance is to be detected. The correlator output is fed through an amplifier circuit including an automatic gain control circuit when the delay is n'.t and the automatic gain control circuit is inoperative when the delay is n.t.

Abstract: In a doppler VOR, a plurality of antennas (1) are arranged equidistantly on a circle (20). Two opposite antenna pairs on the circle are simultaneously activated by a commutator (13) in a manner to simulate as uniform a rotation of two opposite antennas as possible. Reciprocal power dividers (12) are disposed in the lines (15) between the commutator and the antennas. They couple out a given portion of the transmitter signal and transfer it to the two next antennas but one (I, V) in relation to an active antenna (III). These two antennas (I, V), the active antenna (III), and the two intermediate antennas (II, IV), which act as parasitic elements, form an antenna group. Since two adjacent antennas are active simultaneously, two antenna groups are active simultaneously. Their radiation patterns are approximately elliptical.

Abstract: A tracking servo compensator is disclosed for radar systems which steer their antenna beams using a servomechanism that physically moves the antenna. The disclosed tracking servo compensator permits switching between trackers (e.g. from area to point track) and from one tracked target to another without undesirable transients that could cause loss of track. Rate aiding and target range estimates are provided when tracker base motion is known. The compensator works by providing a servo signal that continually monitors the error in estimated track point line-of-sight angular velocity independent of which tracker is employed or the target being tracked. When base motion is known, this signal is used to update the target range estimate so that an accurate rate aiding signal is available. The servo provides smooth controlled-speed transitions between track points during mode switching, and provides an input for manual slewing of the tracker platform during offset track conditions.

Abstract: A split gate, leading edge range tracking apparatus for use in coherent radar seekers is substantially balanced in noise. The early and late gate widths and channel gains are chosen to provide leading edge tracking while avoiding range drift during target fade. A relationship is derived whereby the ratio of the early and late gate widths equals the square root of the ratio of the late and early gate channel gains.