US 5,339,080 AGranted

Earth-penetrating synthetic image radar

AssigneeColeman Research Corporation

InventorsWilliam J. Steinway, James E. Thomas, Carl R. Barrett, Buddy G. Beck

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Abstract

An earth-penetrating synthetic image radar system includes a frequency generator, a transmitter, a microprocessor-based timing and frequency controller, a reference receiver, a parallel polarized receiver, an orthogonal polarized receiver, a digitizer, a calibration processor, a position measurement reference, and an image processor. A plurality of frequency synthesizers are utilized within a single frequency generator to transmit a fast-stepped synthetic image containing a series of discrete frequencies. A switch is used to select between the outputs of the synthezisers for control of the transmitter's frequency output. With a first synthesizer of a frequency f.sub.1 selected, a second synthesizer is being directed digitally to change to the next step in the frequency stepping sequence, frequency f.sub.2. The synthesizers are switched into use by the frequency generator in a ping-pong manner; the first synthesizer handling all the odd-number frequencies, the second handling all even-number frequency selections.

Claims3

Dependent claims

A frequency-stepped radar imaging system for gathering data related to at least one characteristic of a subject area, comprising:

frequency generator means for generating a stepped-frequency synthetic radar image, said frequency generator further comprising a plurality of frequency synthesizer means, each capable of outputting a signal at a discrete frequency;
control means for alternately controlling each of said plurality of frequency synthesizer means so that said plurality of frequency synthesizer means alternately step through a series of discrete frequencies;
switching means for alternately selecting said signal output from each of said frequency synthesizer means as a local oscillator signal;
transmitter means for transmitting a radar signal related in frequency to said local oscillator signal;
reference receiver means for creating a reference signal related to said local oscillator signal;
transmission signal receiver means for receiving said radar signal transmitted by said transmitter means;
and,
means for extracting from said reference receiver means and said transmission receiver means said data related to said at least one characteristic of said subject area.

5 more elements

Dependencies are inferred from the claim text.