Mark Resources, Inc.

Richard L Mitchell

August W Rihaczek

It is common practice in modern radar to utilize some type of downconversion to an intermediate frequency or baseband before analog-to-digital conversion takes place. Several microwave components are needed for this downconversion process, including a tunable local oscillator, bandpass filters, amplifiers, and other signal conditioning devices. The present invention eliminates many microwave components in the radar receiver by sampling the received signal directly, without downconversion or mixing. The manipulation of the received signals that was formerly done with microwave hardware is now done in a digital signal processor. In addition to simplifying the receiver hardware, this invention will also lead to better utilization of the frequency band, less interference from adjacent bands, improvements in system reliability and stability, reduction in system operation and maintenance costs, and will facilitate future system modifications and upgrades.

Direct sampling of received signals in radar

An all-solid-state marine radar technology based on a non-rotating cylindrical array antenna is described. Multiple transmit/receive (T/R) modules are used to form the antenna beam, which allows the beam sequencing, the dwell time in each beam position, the resolution, and the beam shape to be varied in order to make best use of the available energy. Waveforms with a high duty ratio can be used on transmit in order to make efficient use of solid-state power amplifiers. High resolution in both range and Doppler provides high measurement accuracy and superior performance in clutter. Alternate embodiments, including continuous waveform embodiments are disclosed.

Marine radar based on cylindrical array antennas with other applications

An all-solid-state marine radar technology based on a non-rotating cylindrical array antenna is described. Multiple transmit and receive modules are used to form the antenna beam, which allows the beam sequencing, the dwell time in each beam position, the resolution, and the beam shape to be varied in order to make best use of the available energy. Waveforms with a high duty ratio can be used on transmit in order to make efficient use of solid-state power amplifiers. High resolution in both range and Doppler provides high measurement accuracy and superior performance in clutter. Alternate embodiments, including continuous waveform embodiments are disclosed.

A non-scanning radar for detecting and tracking multiple moving objects. The transmit antenna continuously illuminates the entire surveillance volume, which can even be omni-directional (hemispherical). Multiple receive antennas are employed, each covering part of the surveillance volume. Receivers are used in combination to measure angles of incidence via interferometry on objects that are resolved in range and Doppler. Very long processing times are used to compensate for the reduced antenna gain compared to any radar that scans. By continuously illuminating the surveillance volume, there is no hard limit to the number of objects that can be simultaneously tracked. The primary application for this technology is detection and tracking of such objects as bullets, artillery projectiles, mortar shells, and rockets, and determining the location of the weapon that fired them. Numerous other applications are also described.

Radar system for continuous tracking of multiple objects

Radar for detecting and tracking short range airborne targets using a non-scanning beam to illuminate the entire search space, and processing the return signals from a plurality of spaced apart receive antennas. Target angle in one plane may be determined by coherent processing of the returns from the plurality of receive antennas. Spacing the receive antennas apart in three dimensions allows determining of two angles, such as azimuth and elevation. Processing of the returns may be coherent or noncoherent, or returns may be processed both coherently and noncoherently. Programmability of the processing algorithms and parameters provide flexibility in applications, as well as flexibility based on such things as the target type and its range. Exemplary applications are disclosed.

Non-scanning radar for detecting and tracking targets

A concept is described for broadening the beam of a phased array radar antenna to provide continuous illumination of all radar targets within the search space, and this beam is compressed upon reception to realize the angular resolution that is possible with the antenna. The process is analogous to pulse compression. The advantages of the long dwell times provided by this concept include superior clutter suppression performance, more accurate tracking of targets, and the ability to analyze the target returns for reliable discrimination, classification and identification. The broad beam also reduces the power seen by an intercept receiver, for increased covert operation. This is all accomplished without any sacrifice in power. Various embodiments are disclosed.

Beam compression radar

Apparatus and methods are disclosed in which a radar target can be electronically disguised to appear like another target. The technique is based on the generation of a desired synthetic target signature that is superimposed on the normal radar echo for the simulation platform. The simulation system consists of multiple antennas with tapped delay lines and signal modulators to provide the means of generating the desired target signal that is extended in angle and range. It is possible to utilize very realistic models of the desired target; the necessary information can be collected on a high-resolution measurement range. The general technique works against any pulsed radar in a monostatic geometry. A modified technique for operation against continued wave and bistatic radars is also discussed. The applications of the technique include the testing of missileborne guidance radars against cooperative targets and electronic countermeasures (ECM) applied to a target vehicle to deceive the radar. In either case, the physical target will be electronically augmented so that it appears like an entirely different target to the radar.

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Palos Verdes, CA, United States of America

Richard L Mitchell