Radar apparatus and method for detecting small slow moving targets
OwnerJames C. Lawlessinventor
Life of this patent
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Abstract
Radar method and apparatus for detecting small, slow moving targets in the presence of high background clutter that includes a balanced bridge structure to achieve a null balance with the target and background clutter. Radar return signals from background objects as well as the targets are viewed by the radar as a composite single signature return. The invention uses a phase shifter to achieve a null balance even though the background clutter consists of many components at varying distances from the radar.
Claims18
Radar apparatus for detecting at least one small, slow moving target comprising:
- a radio frequency (RF) source having an RF signal as output;
- a phase shifter for producing a phase adjustment in a first portion of the RF signal, the phase adjustment chosen to initially cause a difference signal representing a position change of the at least one target to be substantially zero;
- an antenna arrangement for transmitting the phase adjusted RF signal to at least one target and receiving a reflection of the phase adjusted RE signal from at least one target;
- and
- a mixer for comparing a remainder of the RF signal with the reflection of the phase adjusted RF signal to produce the difference signal.
Radar apparatus for detecting at least one small, slow moving target comprising:
- a radio frequency (RF) source having an RF signal as output;
- a first phase shifter for producing a phase adjustment in a first portion of the RF signal, the phase adjustment chosen to initially cause a difference signal representing a position change of the at least one target to be substantially zero;
- a second phase shifter for modulating the phase of the phase adjusted RF signal at a modulation frequency;
- a modulator for controlling the modulation frequency;
- an antenna arrangement for transmitting the modulated phase adjusted RF signal to the at least one target and receiving a reflection of the modulated phase adjusted RF signal from the at least one target
- a mixer for comparing a remainder of the RF signal with the reflection of the modulated phase adjusted RF signal to produce the difference signal.
A method of radar detecting at least one small, slow moving target comprising:
- (a) generating a radio frequency (RF) signal;
- (b) producing a phase adjustment in a first portion of the RF signal, the phase adjustment chosen to initially cause a difference signal representing a position change of the at least one target to be substantially zero:
- c) transmitting the phase adjusted RF signal to at least one target;
- (d) receiving a reflection of the phase adjusted RF signal from at least one target;
- and
- (e) comparing a remainder of the RF signal with the reflection of the phase adjusted RF signal to produce the difference signal.
Dependencies are inferred from the claim text.