US 5,325,095 A · Stepped frequency ground penetrating radar

Abstract

A stepped frequency ground penetrating radar system is described comprising an RF signal generating section capable of producing stepped frequency signals in spaced and equal increments of time and frequency over a preselected bandwidth which serves as a common RF signal source for both a transmit portion and a receive portion of the system. In the transmit portion of the system the signal is processed into in-phase and quadrature signals which are then amplified and then transmitted toward a target. The reflected signals from the target are then received by a receive antenna and mixed with a reference signal from the common RF signal source in a mixer whose output is then fed through a low pass filter. The DC output, after amplification and demodulation, is digitized and converted into a frequency domain signal by a Fast Fourier Transform. A plot of the frequency domain signals from all of the stepped frequencies broadcast toward and received from the target yields information concerning the range (distance) and cross section (size) of the target.

Claims18

Dependent claims

A stepped frequency ground penetrating radar system comprising:

a) RF signal generating means for generating an RF signal;
b) transmitting means including means for forming in-phase and quadrature RF signals from said RF signal and transmitting said in-phase and quadrature RF signals to a target spaced from said transmitting means;
c) receiving means for receiving reflected RF signals from said target and for mixing said reflected RF signals with a reference RF signal from said same RF signal generating means;
and
d) signal processing means for processing said signals to provide data indicating the depth and size of said target.

2 more elements

A stepped frequency ground penetrating radar system comprising:

a) RF signal generating means including:
i) means for generating a first RF signal;
ii) means for generating a second RF signal;
ii) means for controlling said RF signals, comprising a phase locked loop;
and
iii) means for dividing each of said RF signals into a first RF signal portion to be transmitted and a second RF signal portion to act as a first reference RF signal;
and
iv) first mixer means for mixing together said second RF signal portion of each of first and second RF signals to form said first RF reference signal;
b) transmitting means for transmitting a first portion of each of said first and second RF signals to a target spaced from said transmitting means comprising:
first isolator means for providing spectral purity in said first portion of said first RF signal;
means for forming an in-phase signal and a quadrature signal from said first portion of said first RF signal;
iii) second isolator means for providing spectral purity in said first portion of said second RF signal comprising a second RF reference signal;
iv) second mixer means for mixing said in-phase and said quadrature RF signals with said first portion of said second RF signal from said second isolator means comprising said second reference signal;
v) amplifier means for amplifying said signal from said second mixer means;
and
vi) first antenna means for transmitting said amplified signal to said target;
c) receiving means for receiving a reflected RF signal from said target comprising:
i) second antenna means for receiving reflected signals, including said in-phase and quadrature RF signals, from said target;
ii) third mixer means for mixing said reflected signal from said target with said first RF reference signal portion from said first mixer;
iii) low pass filter means for filtering the output from said third mixer;
iv) amplifier means for amplifying the output signal from said low pass filter means;
v) means to demodulate the amplified output signal from said low pass filter means;
and
d) signal processing means for processing said signals to provide data indicating the depth and size of said target.

21 more elements

Dependencies are inferred from the claim text.

Stepped frequency ground penetrating radar

Life of this patent

Stepped frequency ground penetrating radar

Life of this patent

Abstract

Claims18