Radar system for manmade device detection and discrimination from clutter

• US 20090135046A1
• Filed: 11/28/2007
• Published: 05/28/2009
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Steele, Daniel W., Rotondo, Frank S., Houck, Jeffrey L.
• Granted Patent: US 7,830,299 B2
• Time in Patent Office: Days
• US Class Current: 342/27
• CPC Class Codes: G01S 13/5242 with means for platform motion or scan motion compensation, e.g. airborne MTI
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter

Abstract

A radar system for detecting the presence of threat providing electronic manmade devices placed in a given area of operation comprising: a radar transmitter for transmitting a radar signal designated as a probe signal to the given area of operation to cause said threat providing devices to produce anomalous energy signals, a radar receiver for receiving a reflected radar signal from said area of operation including said anomalous energy signals, designated as Target Anomalous Response (TAR) signals, a circuit responsive to the received signal for processing the signal to detect the (TAR) anomalous energy signals indicative of a threat producing device.

Claims

1. A radar system for detecting the presence of at least one threat providing passive electronic device placed in a given area of operation comprising:

a radar transmitter for transmitting a radar signal designated as a probe signal to said given area of operation to cause said at least one threat providing device to produce anomalous energy signals,

a radar receiver for receiving a reflected radar signal from said area of operation including said anomalous energy signals, designated as Target Anomalous Response (TAR) signals,

means responsive to said received signal for processing said signal to detect said (TAR) anomalous energy signals indicative of said at least one threat producing device.

2. The radar system according to claim 1, wherein said probe signal contains two carrier frequencies separated by a known frequency to cause said at least one threat providing device to generate a family of anomalous energy signals with each signal in said family separated from a neighbor signal by said known frequency.

3. The radar system according to claim 2, wherein said at least one threat providing electronic device includes a radio receiver having electronic circuitry containing one or more non-linear devices responsive to said probe signal to cause said threat providing electronic device to produce TAR signals.

4. The radar system according to claim 2, wherein said at least one threat providing electronic device includes a radio transmitter associated with an antenna, wherein said antenna receives said probe signal to mix with the threat transmitted signal to produce said TAR signals.

5. The radar system according to claim 1 wherein said means responsive to said received signal includes a correlator for processing said received signal to provide amplified TAR signals.

6. The radar system according to claim 1, wherein said radar receiver includes a bank of filters, each filter having a different frequency bandwidth to selectively propagate a different frequency TAR signal at a filter output.

7. The radar system according to claim 1, wherein said radar transmitter is an airborne transmitter.

8. The radar system according to claim 1 wherein said radar transmitter is a surface transmitter.

9. The radar system according to claim 1, further including an interceptor positioned to receive said reflected radar signals from said area of operation and to process said signals to provide TAR signals.

10. A method of detecting manmade devices as those employed to create threats and destruction using electronic circuits located on unmanned vehicles, present in an area of operation, said method comprising the steps of:

transmitting radar probe signals into said area of operation to cause said electronic circuits to produce anomalous RF energy signals designated as Target Anomalous Response (TAR) signals,

receiving reflected radar probe signals and said TAR signals from said area of operation,

processing said received signals to isolate said TAR signals,

determining said threat by responding to said processed TAR signals.

11. The method according to claim 10, wherein said electronic circuits into which said transmitted probe signals enter cause said receiver to produce TAR signals indicative of the presence of said radio receiver.

12. The method according to claim 10, wherein said electronic circuits include a radio transmitter associated with an antenna where said transmitted probe signals cause said radio transmitter to produce TAR signals indicative of the presence of said radio transmitter.

13. The method according to claim 12, wherein said electronic circuits includes an active transmitter associated with an antenna, wherein RF power from said active transmitter mixes with said probe signal to produce high power level TAR signals.

14. The method according to claim 10, further including the step of:

filtering said received signals via a plurality of filters to provide a plurality of TAR signals.

15. The method according to claim 10, wherein the step of transmitting radar probe signals includes simultaneously transmitting two carrier signals separated by a known frequency to cause said electronic circuits to produce a family of TAR signals with each signal component separated form its neighbor by the carrier frequency separation within the probe signal.

16. The method according to claim 10, further including the step of processing said received signals with a signal correlator to provide additional detection sensitivity, wherein said transmitted probe signal is suppressed by said correlator.

17. The method according to claim 10, further including the step of storing said isolated TAR signals indicative of a particular threat.

18. The method according to claim 16, wherein said signal correlator applies correlation gain to said TAR signals while suppressing other received signal components.

19. The method according to claim 10, wherein the step of transmitting said radar probe signals includes transmitting from an aircraft.

20. The method according to claim 10, wherein the step of transmitting said radar probe signals includes transmitting from a surface ground station.

21. A radar system for detecting the presence of at least one threat providing passive electronic device placed in a given area of operation comprising:

a first radar subsystem including;

a first transceiver operative in a first mode for transmitting a first waveform radar signal and in a second mode for receiving return signals;

a second radar subsystem remote from said first radar subsystem and including;

a transmitter operative for transmitting a second waveform radar signal;

a communication link between said first and said second radar subsystems for synchronizing transmission of said first and second waveform radar signals;

wherein said first and second waveform signals cause said at least one threat providing device to produce anomalous energy signals, and

a signal processor responsive to said returned signals for processing said signals to detect said (TAR) anomalous energy signals indicative of said at least one threat producing device.

22. The radar system of claim 21, wherein said first radar subsystem is mobile and said second radar subsystem is fixed.

23. The radar system of claim 21, wherein said first radar subsystem is airborne and said second radar subsystem is a fixed terrestrial subsystem.

24. The radar system of claim 21, wherein said signal processor is contained within said first radar subsystem.

25. The radar system of claim 22, wherein said signal processor compensates for Doppler shift associated with the mobile platform.