Abstract: A multibeam radar system. A matrix or inverse matrix indicating the characteristics of beams of ultrasonic waves or radio waves are previously created for each individual scanning direction (channel) and stored in a memory. Physical quantities corresponding to the intensities of echo signals and to the distance to an object are detected, and temporarily stored in another memory together with the corresponding scanning directions. Those of the temporarily stored data items which represent physical quantities corresponding to the same distance are arranged in rows or columns corresponding to the scanning directions. Inverse calculation processing, or deconvolution processing, is performed according to the matrix or inverse matrix indicating the beam characteristics. In this way, the reception level is corrected.

Abstract: A method for determination of positions of measurement objects from a number of measurements of the directions to the measurement objects made at separate points in time. During the initial measurements of the directions to the measurement objects, a number of assumed areas, within which the measurement objects are assumed to be located, are established along the direction to each measurement object. Subsequent measurements of the directions to the measurement objects are performed from at least two different measurement stations, which between the points in time are moved along different paths. In connection with the measurement of the directions to the measurement objects, the positions of the assumed areas are compared with the expected appearances of the measurement objects, and the assumed areas which exhibit the best correlation to the expected appearances of the corresponding measurement object are assumed to represent the positions of the measurement objects.

Abstract: An imaging radar system for generating images of objects disposed behind an obscuring structure. The system comprises a low power, frequency tunable, continuous wave transmitter and an antenna array coupled to the transmitter that includes a transmit antenna and a plurality of receive antennas. A radar receiver is coupled to the antenna array, and a computer processor is coupled to the radar receiver that comprises a digital signal processor and a computer. A radar display is coupled to the computer for displaying the images of the objects disposed behind an obscuring structure. A power source is coupled to the antenna array, the transmitter, the radar receiver, and the computer processor for providing power thereto. Time difference of arrival processing is performed in the computer for providing radar angle scanning upon receipt of radar return signals from the objects using the antenna array.

Abstract: An error-free tracking system is disclosed which can operate with a scanning sensor. Beginning with an initialized trajectory for an object, predictions are made with respect to future object position and the sensor produces an error signal representing an error between sensor position (predicted target position) and actual target position at the measurement time. From a sequence of error signals, trend information is extracted and, on the basis of the trend information, the gain of a trajectory correction algorithm is adjusted. Based on the corrected trajectory, a new position estimate is determined. This further estimate is then used for another measurement to produce a further error signal in order to provide for tracking the object or target.

Abstract: A time-sharing FM radar system. A plurality of beam radiating and receiving means, an FM signal generating means, a transmitting unit, a receiving unit, and a direction detecting means are configured to minimize power consumption and interference between channels. The beam radiating and receiving means are arranged to radiate partially overlapping beams in space and to receive return beams. The FM signal generating means generates an FM signal. The transmitting unit includes a plurality of transmitting switching circuits each comprised of a plurality of amplifiers. Each amplifier corresponds to one of the beam radiating and receiving means, and is configured to intermittently amplify and distribute a portion of the FM signal generated by the FM signal generating means to its corresponding beam radiating and receiving means. The receiving unit includes a plurality of receiving switching circuits and a single mixer.

Abstract: A lower-frequency compact radar system for wide-angle surveillance. Direction-finding receive antennas consisting of colocated orthogonal electric and magnetic dipoles provide target angles from the radar. The size of this antenna unit is reduced to the point where internal noise is comparable to external to achieve maximum compactness. High sensitivity is achieved with an efficient class of pulsed/gated, linearly swept-frequency waveforms that are generated and processed digitally. For backscatter radars, close to 50% duty factors are realized. The rules for waveform design and processing overcome problems of range/Doppler aliasing and/or blind zones. After mixing in the receiver, processing bandwidths are much less than RF signal bandwidths, so that simple, inexpensive personal computers are used for real-time signal processing. Digital FFT algorithms determine target range and Doppler, and DF algorithms determine its angles.

Abstract: A frequency modulated-continuous wave (FM-CW) radar system for detecting a range, relative speed, and direction to a target. To this end, a beat signal generator, first and second signal distributors, a beat signal frequency detector, a beat signal amplitude level detector, and at least one pair of antennas are provided. Each antenna of each pair has the same directivity, is set to radiate a beam in a slightly different direction from the beam radiated by the other antenna, and is set to receive a return beam from a target. The first signal distributor distributes an FM signal having a frequency varying with time to each of said antennas successively and repeatedly. The second signal distributor distributes a reference FM signal to a first set of input terminals of the beat signal generator successively and repeatedly.

Abstract: A frequency modulated-continuous wave (FM-CW) radar system for detecting a range, relative speed, and direction to a target. To this end, a beat signal generator, first and second signal distributors, a beat signal frequency detector, a beat signal amplitude level detector, and at least one pair of antennas are provided. Each antenna of each pair has the same directivity, is set to radiate a beam in a slightly different direction from the beam radiated by the other antenna, and is set to receive a return beam from a target. The first signal distributor distributes an FM signal having a frequency varying with time to each of said antennas successively and repeatedly. The second signal distributor distributes a reference FM signal to a first set of input terminals of the beat signal generator successively and repeatedly.

Abstract: A continuous emission radar device for determining, at short range, the relative positions of a missile and a vehicle to which the device is fitted, includes a transmitting circuit connected to a transmitting antenna for emitting a continuous signal modulated by a pseudo-random binary sequence delivered at a clock frequency fH, and three receiving circuits connected respectively to three receiving antennae which receive echos of the emitted signal from the missile, a first receiving circuit generating the clock frequency and slaving it to the missile vehicle distance, and the other two receiving circuits determining the phase shift between the echo received by the first antenna and each of the echos received by the other two antennae, these three parameters being transmitted to a device for calculating the position of the missile in relation to the vehicle.

Abstract: A radar target locating and tracking apparatus utilizing a data processor unit to process a dual-interleaved pulse train radar waveform to provide unambiguous target location. The data processor utilizes coarse range, fine range and Doppler signals which are derived from the transmitted non-ideal waveform to resolve ambiguities in target location.

Abstract: A pulse radar apparatus is provided with a transmitter (1), a transmitting antenna (2) and a receiving antenna system (3) with a first and a second receiving channel (4 and 5) coupled thereto. The receiving antenna system (3) comprises N stacked receiving antennas (A.sub.0, A.sub.1, . . . , A.sub.N-1). The first receiving channel (4) comprises N receiving circuits (B.sub.0, B.sub.1, . . . , B.sub.N-1), each connected to a corresponding receiving antenna (A.sub.0, A.sub.1, . . . , A.sub.N-1) and each processing the particular echo signal into two orthogonally phase-detected and digitized video signal components, and a beamformer (14) to derive from said components the orthogonal components I.sub.k, Q.sub.k of the video signal determined jointly by the N receiving circuits in accordance with a receiving beam pattern k corresponding with a specific elevation interval. The second receiving channel (5) comprises N receivers (B.sub.0, B.sub.1, . . . , B.sub.

Abstract: A radar having a multiplicity of receive beams stacked in elevation and a target height extractor especially for use therein are disclosed. In operation, a set of range sweeps corresponding to an azimuth scan of the stacked receive beams across a detected target is established. A range cell interval corresponding to the detected target is estimated for each range sweep of the set. A target range measurement is computed from a set of estimated range intervals. Only the radar receive beam echo information corresponding to the estimated range cell interval for each range sweep of the established set is used by the height extractor to compute a corresponding set of elevation angles. A target elevation angle is formed as the weighted average of this computed set. Only one height computation is performed for each established set of range sweeps based on a function of factors including the computed target elevation angle and computed range measurement of the corresponding established set of range sweeps.

Abstract: A system for simultaneously locating a plurality of targets and distinguishing the targets from noise which utilizes phase detector techniques to generate complex voltage signals and obtain phase information. Spectral analysis is performed on the complex voltage temporal functions to generate doppler frequency functions. Both spectral phase functions and spectral amplitude functions are generated from the doppler frequency functions. Spectral phase functions are analyzed using interferometry techniques to determine if a potential target has a common locational source from returns of a plurality of sensors. A zenith angle is also generated using interferometry techniques to provide locational information of the multiple targets. Range gating and two frequency range detection methods provide high resolution range information as to the location of the targets. High resolution range information and two dimensional zenith angle information are used to provide an image of the targets.