Electronics & Space Corporation

Thomas L Grettenberg

David Lamper

A waveform generator (12') is responsive to a reference clock signal input for producing an output waveform which is a linear FM waveform. A reference clock signal is supplied to the generator which performs a double integration to obtain the phase of the output signal. The phase resulting from the double integration is used to obtain the sine of the phase using a lookup table. The sine of the phase is input to digital-to-analogue (D/A) converter, and the output from the D/A converter is filtered using a bandwidth matched to the bandwidth of the transmitted signal. The generator is useful in radar systems for area mapping and target identification.

Waveform generator

A method of providing motion compensation (i.e. phase, doppler frequency, and range closure correction) for wide band synthetic aperture radar (SAR) or classification/identification radar modes is disclosed. An improved radar system employing the method is also disclosed. The method involves dividing the motion compensation into both a focusing function and a range closure function. Either or both these functions is achieved by modifying the transmitted signal. For stretch waveform processing systems, the method involves generating both the transmitted and reference signals. The radar system includes a waveform generator capable of implementing the various motion compensation techinques when the transmitted waveform is a linear FM waveform.

Radar system employing a method for motion and range closure compensation

A method of signal processing for use in high duty factor radars for detecting targets at ranges both shorter and longer than a minimum range defined by a transmitted pulse having a defined pulse length. A coded pulse coherent array waveform is transmitted and a return signal which is a waveform reflected off a target is received. The reflected waveform is sampled and time shifted by adding data to its beginning and end. The vector is then processed (pulse compressed) to obtain target information. Target information can now be obtained which is normally in a 'blind zone', because the distance of the target from the radar is such that it appears during an interval when sampling is not done because of waveform transmission.

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St. Louis, MO, United States of America

Thomas L Grettenberg