MOVING-ENTITY DETECTION

• US 20090262005A1
• Filed: 02/24/2009
• Published: 10/22/2009
• Est. Priority Date: 04/14/2005
• Status: Active Grant

• Current Assignee: L3harris Fuzing and Ordnance Systems Incorporated
• Original Assignee: L-3 Communications CyTerra Corporation (L3Harris Technologies, Inc.)
• Inventors: Mackey, Todd, McNeill, James, Dyson, Tim
• Granted Patent: US 9,063,232 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01S 13/38 wherein more than one modulation frequency is used
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 13/9029 specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G01S 7/038 Feedthrough nulling circuits
• CPC Class Codes: G01S 7/35 Details of non-pulse systems
• CPC Class Codes: G01S 7/4004 of parts of a radar system

Abstract

A system and method for enabling transmission of a stepped-frequency radar signal can involve a first antenna and a second antenna. The system can also involve receiving circuitry configured to receive detected reflections from the antennas and to generate data including information associated with frequency and phase shifts. The system can further involve a processor configured to receive the generated data from the receiving circuitry and to analyze the generated data to determine information associated with a moving object located at a side of a wall opposite to the system by differentiating reflections of the transmitted signal detected with the first antenna from reflections of the transmitted signal detected with the second antenna.

Claims

1. A method for detecting entities based on movement, the method comprising:

transmitting a stepped-frequency radar signal from a first side of a wall to a second side of the wall;

detecting reflections of the transmitted signal with a first antenna at a first detection location and with a second antenna at a second detection location;

generating data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location and with the second antenna at the second detection location; and

analyzing the generated data to determine information associated with a moving object located beyond the second side of the wall, the analysis including differentiating reflections of the transmitted signal detected with the first antenna at the first detection location from reflections of the transmitted signal detected with the second antenna at the second detection location.

2. The method of claim 1 wherein the second detection location

is spaced along at least a first axis from the first detection location, the method further comprising:

detecting the reflections of the transmitted signal with a third antenna at a third detection location, the third detection location being spaced along at least a second axis from the first or second detection locations, wherein the second axis is perpendicular to the first axis.

3. The method of claim 2 wherein:

generating the data includes generating data associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first, second, and third antennas;

determining the information associated with a moving object includes analyzing the data associated with the frequency shifts to identify a presence of the moving object; and

differentiating the reflections of the transmitted signal includes using differences between the phase shift of reflections as detected with the first, second, and third antennas to determine a location of the moving object defined by multiple spatial dimensions.

4. The method of claim 3 further comprising rendering, on a display screen, an indication of the determined location of the identified moving object relative to location of the display screen in the multiple spatial dimensions.

5. The method of claim 1 wherein transmitting the stepped-frequency radar signal includes:

transmitting a first stepped-frequency radar signal at the first side of the wall to the second side of the wall; and

concurrently transmitting a second stepped-frequency radar signal at the first side of a wall to the second side of the wall.

6. The method of claim 5 wherein:

transmitting the first stepped-frequency radar signal includes transmitting the first stepped-frequency radar signal at a first transmit location; and

concurrently transmitting the second stepped-frequency radar signal includes concurrently transmitting the second stepped-frequency radar signal at a second transmit location.

7. The method of claim 6 further comprising:

differentiating the reflections of the first transmitted signal transmitted at the first transmit location with reflections of the second transmitted signal transmitted at the second transmit location; and

analyzing the data from the differentiated reflections to account for differences between the data associated with the phase shifts of the first and second transmitted signals which results from the spatial difference between the first and second transmit locations.

8. The method of claim 1 wherein:

transmitting the stepped-frequency radar signal includes beginning transmission of the stepped-frequency radar signal with a system at a first system location and moving the system during transmission of the stepped-frequency radar signal from the first system location to a second system location;

detecting the reflections of the transmitted signal includes detecting reflections of the transmitted signal during the movement of the system from the first system location to the second system location; and

analyzing the generated data includes determining the information associated with the moving object located beyond the second side of the wall based upon the reflections detected during the movement of the system from the first system location to the second system location.

9. The method of claim 8 further comprising determining system motion as reflections of the transmitted signal are detected during the movement of the system from the first system location to the second system location, wherein:

generating the data includes generating data for detected reflections which includes information associated with frequency and phase shifts and associated with a corresponding system motion as determined when the reflection was detected; and

analyzing the generated data includes generating a synthetic aperture radar image using the data including information associated with frequency and phase shifts and associated with a corresponding system motion.

10. The method of claim 9 wherein:

determining the system motion as reflections of the transmitted signal are detected during the movement of the system includes sampling output of an inertial sensor within the system; and

generating the data includes generating a packet of data for reflections received at each of multiple system locations between the first and second system locations, each packet including the information associated with frequency and phase shifts and output of the sampled inertial sensor at the time the reflection was detected.

11. The method of claim 1 further comprising:

identifying a transmit-to-receive leakage signal resulting from the transmission of the stepped-frequency radar signal;

generating a cancellation waveform configured to remove effects of the identified transmit-to-receive leakage signal; and

using the generated cancellation waveform to remove effects of transmit-to-receive leakage signal of subsequent transmissions.

12. The method of claim 1 further comprising:

after transmitting the stepped-frequency radar signal, determining the stepped-frequency radar signal should be altered; and

transmitting an altered stepped-frequency radar signal based upon the determination that the stepped-frequency radar signal should be altered.

13. The method of claim 12 further comprising generating the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having one or more of the transmitted frequencies removed.

14. The method of claim 12 further comprising generating the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having the order of the transmitted frequencies changed.

15. The method of claim 1 wherein the first antenna is a forward looking antenna and the second antenna is a backwards looking antenna.

16. A system for detecting entities based on movement, the system comprising:

transmission circuitry configured to enable transmission of a stepped-frequency radar signal;

a first antenna configured to detect reflections of the transmitted signal at a first detection location of the system;

a second antenna configured to detect reflections of the transmitted signal at a second detection location of the system;

receiving circuitry configured to receive the detected reflections from the first and second antennas and to generate data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location of the system and with the second antenna at the second detection location of the system; and

a processor configured to receive the generated data from the receiving circuitry and to analyze the generated data to determine information associated with a moving object located at a side of a wall opposite to the system, the analysis including differentiating reflections of the transmitted signal detected with the first antenna at the first detection location of the system from reflections of the transmitted signal detected with the second antenna at the second detection location of the system.

17. The system of claim 16 wherein the receiving circuitry is a part of the processor.

18. The system of claim 16 wherein the second detection location of the system is spaced along at least a first axis from the first detection location of the system, the system further comprising:

a third antenna configured to detect reflections of the transmitted signal at a third detection location of the system, the third detection location of the system being spaced along at least a second axis from the first or second detection locations of the system, wherein the second axis is perpendicular to the first axis.

19. The system of claim 18 wherein:

the receiving circuitry is configured to receive the detected reflections from the third antenna and to generate data associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first, second, and third antennas;

to determine information associated with the moving object, the processor is configured to analyze the data associated with the frequency shifts to identify a presence of the moving object; and

to differentiate reflections of the transmitted signal, the processor is configured to use differences between the phase shift of reflections as detected with the first, second, and third antennas to determine a location of the moving object defined by multiple spatial dimensions.

20. The system of claim 19 wherein the processor is configured to enable rendering, on a display screen, of an indication of the determined location of the identified moving object relative to the system in the multiple spatial dimensions.

21. The system of claim 16 wherein the transmission circuitry is configured to enable transmission of a first stepped-frequency radar signal and a second stepped-frequency radar signal concurrently.

22. The system of claim 21 further comprising:

a first transmit antenna configured to transmit at a first transmit location of the system; and

a second transmit antenna configured to transmit at a second transmit location of the system,

wherein to enable transmission of the first and second stepped-frequency radar signals concurrently, the transmission circuitry is configured to enable the concurrent transmission of the first stepped-frequency radar signal with the first transmit antenna and the second stepped-frequency signal with the second transmit antenna.

23. The system of claim 22 wherein:

the receiving circuitry is configured to differentiate reflections of the first transmitted signal transmitted at the first transmit location of the system with reflections of the second transmitted signal transmitted at the second transmit location of the system; and

the processor is configured to account for differences between the data associated with the phase shifts of the first and second transmitted signals which results from the spatial difference between the first and second transmit locations of the system.

24. The system of claim 16 wherein:

the transmission circuitry is configured to enable the transmission of the stepped-frequency radar signal to begin at a first system location and to continue during movement of the system from the first system location to a second system location;

the receiving circuitry is configured to receive the detected reflections of the transmitted signal during the movement of the system from the first system location to the second system location; and

the processor is configured to determine the information associated with the moving object located at the side of the wall opposite to the system based upon the reflections detected during the movement of the system from the first system location to the second system location.

25. The system of claim 24 further comprising a motion sensor configured to determine system motion as reflections of the transmitted signal are detected during the movement of the system from the first system location to the second system location, wherein:

the receiving circuitry is configured to generate data for detected reflections which includes information associated with frequency and phase shifts and information associated with a corresponding system motion as determined by the motion sensor when the reflection was detected; and

the processor is configured to generate a synthetic aperture radar image using the data including information associated with frequency and phase shifts and information associated with a corresponding system motion.

26. The system of claim 25 wherein:

the motion sensor is an inertial sensor; and

to generate data for detected reflections which includes a corresponding system motion, the receiving circuitry is configured to sample output of the inertial sensor and to generate a packet of data for reflections received at multiple system locations between the first and second system locations, each packet including the information associated with frequency and phase shifts and output of the sampled inertial sensor at the time the reflection was detected.

27. The system of claim 16 wherein the processor is configured to:

identify a transmit-to-receive leakage signal resulting from the transmission of the stepped-frequency radar signal;

generate a cancellation waveform configured to remove effects of the identified transmit-to-receive leakage signal; and

use the generated cancellation waveform to remove effects of transmit-to-receive leakage signal of subsequent transmissions.

28. The system of claim 16 wherein the processor is configured to:

after the transmission of the stepped-frequency radar signal, determine the stepped-frequency radar signal should be altered; and

enable the transmission circuitry to transmit an altered stepped-frequency radar signal based upon the determination that the stepped-frequency radar signal should be altered.

29. The system of claim 28 wherein the processor is configured to enable generation of the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having one or more of the transmitted frequencies removed.

30. The system of claim 28 wherein the processor is configured to enable generation of the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having the order of the transmitted frequencies changed.

31. The system of claim 16 wherein the first antenna is a forward looking antenna and the second antenna is a backwards looking antenna.

32. The system of claim 16 wherein:

the first antenna is a transceiver; and

to enable transmission of the stepped-frequency radar signal, the transmission circuitry is configured to enable transmission of the stepped-frequency radar signal with the first antenna.

33. A system for detecting entities based on movement, the system comprising:

transmission circuitry configured to enable transmission of a stepped-frequency radar signal;

a first antenna configured to detect reflections of the transmitted signal at a first detection location of the system;

a second antenna configured to detect reflections of the transmitted signal at a second detection location of the system;

receiving circuitry configured to receive the detected reflections from the first and second antennas and to generate data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location of the system and with the second antenna at the second detection location of the system; and

processing means to analyze the generated data to determine information associated with a moving object located at a side of a wall opposite to the system, the analysis including differentiating reflections of the transmitted signal detected with the first antenna at the first detection location of the system from reflections of the transmitted signal detected with the second antenna at the second detection location of the system.