Abstract: A radar sensor/processor for intelligent vehicle highway systems. The radar sensor/processor provides the range, speed, identity of, and selective communications with, vehicles equipped with a transponder in a first cooperative interrogator/transponder mode, and provides information on the range and speed of vehicles without a, or with an inoperative, transponder in a second noncooperative mode. The interrogator includes a first direct digital synthesizer, with an associated first input binary tune register, for producing a sine wave output, a multiplier for multiplying the sine wave output to produce an X-band signal, and a bi-phase single sideband modulator which modulates the X-band signal with data to be transmitted. The interrogator receiver receives a returned transponder reply signal, and includes a balanced mixer for downconverting the reply signal.

Abstract: An ultra-wideband impulse radar system for use on an airborne platform includes circuitry for coherently integrating the signals to improve signal-to-noise ratio so as to enhance the detection capability of the system, and for motion compensation of the signals to correct for inadvertent modulations of received signals due to buffeting or vibration of the airborne platform which may otherwise corrupt the filtering and signal integration processes. The inclusion of velocity filters and coherent integration despite the lack of phase information in the signals is accomplished by exploiting the time-delay properties of the received impulse signals, in which the observable pulse repetition frequency of the received signals differs from the transmitted pulse repetition frequency by virtue of the relative velocity between signal reflecting elements and the radar platform.

Abstract: Capability is provided using coherent synthetic aperture radar (SAR) techniques for substantially extending the useful range for producing 3 scaled high resolution orthogonal image projections on a CRT of a translating ship under the influence of rotational motions arising from sea state conditions, for the purpose of ship classification and weapon delivery from an airborne platform at long stand-off ranges. This advantage is brought about by determining image coordinates on the basis of range, doppler, and doppler rate measurements of individual scatterers and from ship angular rotational velocities derived from a weighted multivariate regression solution to doppler processed interferometric azimuth and elevation angle measurements of all significant ship target scatterers. In this manner, the image degradation suffered by plotting angular measurements directly, whose location accuracies are known to deteriorate rapidly with increased range due to high signal-to-noise requirements, is circumvented.

Abstract: Distortions inherent in the formation of a range/doppler image by an airborne Synthetic Aperture Radar (SAR) of a ship under the influence of roll, pitch, and yaw motions characteristic of sea state conditions are removed in conjunction with a least squares linear regression solution to doppler processed interferometric azimuth angle data derived from ship radar reflections, resulting in a scaled high resolution range/doppler image representative of the true range/cross range (azimuth) distribution of the ship, so that continuous automatic tracking of a cursor imbedded in a single designated resolution cell of the ship's displayed image, essential to carrying out precision standoff command weapon guidance to that selected ship target cell, can be accomplished.

Abstract: In an airborne radar system, moving ground targets are identified on a cathode ray tube (CRT) display and their motion tracked to allow precise delivery of air-to-ground weapons. Target location errors, due to the effect of target motion upon the doppler frequency of the received signals, and consequent angle measurement ambiguities introduced by the presence of clutter are significantly reduced. The target's radial velocity with respect to the electrical boresight of the system antenna is determined and a corresponding frequency adjustment is made to the processed signal in order to accurately locate the target on the display to lie in precise correspondence to its displayed stationary surroundings.

Abstract: Distortions inherent in the formation of a range/doppler image by an airborne Synthetic Aperture Radar (SAR) of a ship under the influence of roll, pitch, and yaw motions characteristic of a sea state conditions, are removed by the formation of a scaled range/azimuth image generated with the use of an interferometer antenna in conjunction wth the SAR. A least squares linear regression solution to doppler processed interferometric azimuth angle data derived from ship radar reflections permits the determination of aircraft to ship relative rotational motion essential to the development of such an improved high resolution radar image, so that continuous automatic tracking of a cursor imbedded in a single designate resolution cell of the ship's displayed image essential to carrying out precision standoff command weapon guidance to that selected ship target cell, can be accomplished.

Abstract: Capability is provided for producing 3 scaled high resolution orthogonal image projections on a CRT of a ship under the influence of translational as well as rotational motions arising from sea state conditions, for the purpose of ship target identification and classification, and the subsequent carrying out of stand-off command weapon guidance to a designated resolution cell of the ship from an airborne platform. Doppler processed interferometric azimuth and elevation angle measurements of the ship scatterers derived from a coherent synthetic aperture radar are combined in a weighted multivariate regression fit using digital signal processing techniques to provide measures of ship translational and rotational motions essential to providing focussed high resolution imagery and precision standoff weapon delivery to the designated ship target resolution cell. The invention also provides a capability for scaling the cross-range (doppler) dimension of Inverse SAR Profile Imagery.