Method and system for in-air ultrasonic acoustical detection and characterization

• US 6,987,707 B2
• Filed: 11/12/2003
• Issued: 01/17/2006
• Est. Priority Date: 11/12/2002
• Status: Expired due to Fees

• Current Assignee: General Dynamics Mission Systems Inc. (General Dynamics Corporation), Technology Focus LLC
• Original Assignee: General Dynamics Advanced Information Systems Incorporated (General Dynamics Corporation)
• Inventors: Cox, Michael, Reed, Francis A., Borrell, Ronald A., Feintuch, Paul L.
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US10/712,805
• Publication Number:
  US 20050058021A1
• Time in Patent Office: 797 Days
• Field of Search: 367/87, 367/93, 367/99, 367/103, 736/25, 736/28
• US Class Current: 367/99
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/523 for presence detection burglar, theft or intruder alarms G08B13/00, e.g. G08B13/16
• CPC Class Codes: G01S 15/66 Sonar tracking systems
• CPC Class Codes: G01S 15/87 Combinations of sonar systems
• CPC Class Codes: G01S 7/52006 with provision for compensating the effects of temperature
• CPC Class Codes: G01S 7/539 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G08B 13/1618 using ultrasonic detection means

Abstract

A system and method are presented for determining the detection and location of persons and objects using ultrasonic acoustic sensors. The system allows detection of stationary and moving persons and other objects, through atmospheric conditions, to a distance of at least 300 feet. The invention further provides for enhanced signal processing through the use of arrays of transmitters and receivers, where one or more transmitter arrays may be oriented substantially perpendicularly to one or more receiver arrays, allowing high directionality and good rejection of reverberations, background noise, clutter and objects not of interest.

Claims

1. An object detection system for detecting and identifying targets, including:

a first module having a plurality of acoustic transmitters configured to generate a concatenated ultrasonic wavetrain including a first waveform configured to illuminate a target moving at a first speed and a second waveform configured to illuminate a target either moving at a second speed substantially slower than the first speed or being stationary, the wavetrain being transmitted in air and in a predetermined direction;

a second module having at least one acoustic receiver configured to receive reflected ultrasonic waves originating from the first module after reflection from a target; and

target identification logic coupled to the second module and configured to generate an output representative of the target.

2. The detection system of claim 1, wherein the first module includes a plurality of acoustic transmitters and the second module includes a plurality of acoustic receivers.

3. The object detection system of claim 2, wherein:

the acoustic transmitters are positioned in a generally collinear configuration oriented in a first direction;

the acoustic receivers are positioned in a generally collinear configuration oriented in a second direction;

the first direction and the second direction are nonparallel to one another.

4. The object detection system of claim 3, wherein the first direction is substantially perpendicular to the second direction.

5. The object detection system of claim 1, wherein the target identification logic is configured to reduce background noise in the generated output.

6. The object detection system of claim 1, wherein the target identification logic is configured to reduce reverberation in the generated output.

7. The object detection system of claim 1, wherein the first and second modules are configured to minimize energy received at the second module from directions other than a predetermined direction targeted by the transmitter.

8. The object detection system of claim 1, wherein the second module includes at least a first said acoustic receiver and a second said acoustic receiver wherein the first said acoustic receiver is positioned above the second said acoustic receiver.

9. The object detection system of claim 1, further including feature extract logic configured to generate signals representative of at least one physical characteristic of the target.

10. The object detection system of claim 1, wherein the first and second modules are configured to reduce energy from directions other than a predetermined direction targeted by the transmitter.

11. The object detection system of claim 1, further including logic configured to identify targets based upon clusters derived from the reflected acoustic waves.

12. The object detection system of claim 1, wherein the produced ultrasonic waves include concatenated waves of different types.

13. The object detection system of claim 12, wherein the identification logic is configured to reduce reverberation in the generated output.

14. The object detection system of claim 12, wherein the first and second modules are configured to minimize energy received at the second module from directions other than a predetermined direction targeted by the transmitter.

15. The object detection system of claim 12, further including logic configured to correlate data of multiple pings to improve the received data.

16. The object detection system of claim 12, wherein the identification logic is configured to provide cluster analysis of over-resolved echo return from a single object.

17. An area detection system including a plurality of object detection systems for detecting and identifying targets, each object detection system including:

a first module having a plurality of acoustic transmitters configured to generate a concatenated ultrasonic wavetrain including a first waveform configured to illuminate a target moving at a first speed and a second waveform configured to illuminate a target either moving at a second speed that is substantially slower than the first speed or being stationary, the wavetrain being transmitted in air and in a predetermined direction;

a second module having at least one acoustic receiver configured to receive reflected ultrasonic waves originating from the first module after reflection from a target; and

target identification logic coupled to the second module and configured to generate an output representative of the target.

18. The area detection system of claim 17, wherein the generated ultrasonic waves from the respective object detection systems are configured to substantially overlay at a predetermined stand-off range.

19. The area detection system of claim 17, further including integration logic configured to receive the generated outputs from each of the object detection systems and to generate an integrated output representing targets in a predetermined area.

20. The area detection system of claim 19, wherein the integrated logic is configured to eliminate multiple representations of generated ultrasonic waves reflected from a single target.

21. An object detection system including:

(a) a first module having a plurality of acoustic transmitters configured to generate a concatenated ultrasonic wavetrain including a first waveform configured to illuminate a target moving at a first speed and a second waveform configured to illuminate a target either moving at a second speed substantially slower than the first speed or being stationary, the wavetrain being transmitted in air and in a predetermined direction;

(b) a second module having a plurality of receivers configured to receive reflected ultrasonic waves originating from the first module after reflection from a target;

(c) first logic configured to identify targets based upon clusters derived from reflected acoustic waves;

(d) second logic configured to minimize energy received at the second module from directions other than a predetermined direction targeted by the transmitter; and

(e) third logic configured to generate signals representative of at least one physical characteristic of the target and

wherein the acoustic transmitters are positioned in a generally collinear configuration oriented in a first direction;

wherein the acoustic receivers are positioned in a generally collinear configuration oriented in a second direction which is substantially perpendicular to the first direction.

22. A method of acoustically detecting objects, the steps including:

generating a concatenated ultrasonic wavetrain including a first waveform configured to illuminate a target moving at a first speed and a second waveform configured to illuminate a target either moving at a second speed that is substantially slower than the first speed or being stationary, the wavetrain being transmitted in air and in a predetermined direction;

transmitting the generated ultrasonic wavetrain through air towards a target;

receiving ultrasonic waveforms from a set of at least one acoustic receiver configured to receive reflected ultrasonic waves originating from the first module after reflection from the target; and

processing ultrasonic waveforms with target identification logic coupled to the at least one acoustic receiver and configured to generate an output representative of the target.

23. The method of claim 22, further comprising the steps of:

determining whether the received ultrasonic waves are false alarms.

24. The method of claim 22, wherein the ultrasonic waves are received by an array of receivers.

25. The method of claim 22, wherein the ultrasonic waves are generated by an array of transducers.

26. The method of claim 22, wherein the ultrasonic waves are generated by a single transducer.

27. The method of claim 22, wherein the step of processing the received ultrasonic waves includes identifying targets based upon clusters derived from reflected acoustic waves.