Radar system for manmade device detection and discrimination from clutter

• US 7,830,299 B2
• Filed: 11/28/2007
• Issued: 11/09/2010
• Est. Priority Date: 11/28/2007
• Status: Expired due to Fees

• 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.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Bythrow; Peter M
• Application Number:
  US11/998,179
• Publication Number:
  US 20090135046A1
• Time in Patent Office: 1,077 Days
• Field of Search: 342 13- 20, 342/22
• US Class Current: 342/22
• 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, said radar receiver including a bank of filters, each filter having at least one of a different frequency range and resolution that is matched to a given TAR signal such that each filter selectively propagates a different frequency TAR signal from said reflected radar signal at its output, and

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 transmitter is an airborne transmitter.

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

8. 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.

9. 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, and

detecting said threat by analyzing said processed TAR signals,

wherein the step of processing said received signals includes filtering said received signals via a plurality of filters, each of said filters set to a bandwidth matching that of a possible TAR, the output of said filters providing a plurality of TAR signals.

10. The method according to claim 9, wherein said electronic circuits into which said transmitted probe signals enter include a radio receiver and cause said receiver to produce TAR signals indicative of the presence of said radio receiver.

11. The method according to claim 9, 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.

12. The method according to claim 11, 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.

13. The method according to claim 9, 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.

14. The method according to claim 9, 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.

15. The method according to claim 9, further including the step of storing said isolated TAR signals indicative of a particular threat.

16. The method according to claim 14, wherein said signal correlator applies correlation gain to said TAR signals while suppressing other received signal components.

17. The method according to claim 9, wherein the step of transmitting said radar probe signals includes transmitting from an aircraft.

18. The method according to claim 9, wherein the step of transmitting said radar probe signals includes transmitting from a surface ground station.

19. A radar system for detecting the presence of at least one threat providing 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, said receiver further comprising a reference generator for generating a synthesized TAR reference signal,

a correlator responsive to said TAR signals and said synthesized TAR reference signal for providing a signal correlation time record, and

means responsive to said signal correlation time record for processing said record to detect said at least one threat producing device.

20. The radar system of claim 19, wherein the reference generator generates said synthetic TAR reference signal by filtering an un-TARed portion of said received signal and modulating said un-TARed portion with a replica of said probe signal.