Earth-penetrating synthetic image radar

• US 5,339,080 A
• Filed: 04/08/1993
• Issued: 08/16/1994
• Est. Priority Date: 04/08/1993
• Status: Expired due to Fees

• Current Assignee: CyTerra Corp. (L3Harris Technologies, Inc.)
• Original Assignee: Coleman Research Corp. (L3Harris Technologies, Inc.)
• Inventors: Thomas, James E., Beck, Buddy G., Barrett, Carl R., Steinway, William J.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US08/043,715
• Time in Patent Office: 495 Days
• Field of Search: 342/25, 342/22, 342/129
• US Class Current: 342/22
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 7/4065 involving a delay line

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 f₁ selected, a second synthesizer is being directed digitally to change to the next step in the frequency stepping sequence, frequency f₂. 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.

Claims

1. 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.

2. The frequency-stepped radar imaging system according to claim 1, wherein said data related to said at least one characteristic of said subject area comprises data indicating the presence or absence of a container holding hazardous waste.

3. The frequency-stepped radar imaging system according to claim 2, wherein said hazardous waste comprises carbon tetrachloride.