System and method for improving microwave detector performance using ranging microwave function

• US 7,705,730 B2
• Filed: 03/07/2007
• Issued: 04/27/2010
• Est. Priority Date: 03/07/2007
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Royer, Gregory
• Primary Examiner(s): Nguyen; Tai T
• Application Number:
  US11/715,037
• Publication Number:
  US 20080218339A1
• Time in Patent Office: 1,147 Days
• Field of Search: 340/552, 340/567, 340/554, 340/522, 340/506, 340/540, 340/541, 340/545.3, 342/28, 342/161, 342/162
• US Class Current: 340/552
• 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 13/886 for alarm systems alarms with electrical actuation G08B13/22
• CPC Class Codes: G01S 7/2922 by using a controlled threshold
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field
• CPC Class Codes: G08B 29/26 by updating and storing reference thresholds

Abstract

Embodiments of the present invention are directed to a method and system for use of ranging MW to decrease MW intrusion detector false alarms. A Doppler microwave system may be provided that is capable of detecting an object range and adjusting the sensitivity of an alarm stage of a MW detector to account for object size and range. Multiple range limited MW stages may be configured for different ranges to determine the general range of the moving object. Based on signal levels present on these MW stages, an approximate object range may be determined. The sensitivity of the MW alarm stage is then adjusted based on a MW alarm state sensitivity vs. object range function that is optimized to alarm on humans and ignore small animals and insects. The method and system may be used in detection systems incorporating a MW sensor.

Claims

1. A microwave intrusion detector, the system comprising:

a multistage microwave sensing system configured to generate at least one output signal indicative of a presence of a moving object, the multistage microwave sensing system including multiple range bins for classifying microwave signals including a microwave alarm stage bin for determining an alarm state of the microwave intrusion detector a processor coupled to the multistage microwave sensing system to receive the at least one output signal;

a memory accessible by the processor;

a range determination module stored in the memory for execution by the processor to determine an estimated target range based on a state of each of the multiple range bins;

a microwave alarm stage bin sensitivity calculation module stored in the memory for execution by the processor to determine an optimal microwave alarm stage bin sensitivity level based on the estimated target range and an alarm relay operable to trigger an alarm based upon the alarm state indicating a security violation.

2. The system of claim 1, further comprising dynamically adjusting a microwave alarm stage bin sensitivity level to a predetermined threshold upon determination of the target range.

3. The system of claim 1, wherein the multiple range bins comprise at least a short range bin and a long range bin.

4. The system of claim 3, wherein the multiple range bins further comprise an insect range bin and a mid-range bin.

5. The system of claim 4, further comprising a long range bin that functions as the microwave alarm stage bin.

6. The system of claim 5, wherein the insect range bin is capable of detecting insects in an immediate vicinity of the intrusion detector.

7. The system of claim 6, wherein when the insect range bin detects a target, the microwave alarm stage bin sensitivity determination mechanism determines that the optimal microwave alarm stage bin sensitivity level is a low sensitivity and a microwave alarm trigger requires high amplitude pulses.

8. The system of claim 6, wherein when the insect range bin detects a target, the microwave sensitivity determination mechanism triggers a time delay, beginning at insect range bin target detection, and terminating at some fixed time after clearance of the insect range bin, wherein alarm stage bin microwave signals are ignored during the time delay.

9. The system of claim 5, wherein the short range bins detects crawling intruders under or in the vicinity of the intrusion detector.

10. The system of claim 5, wherein a target within the short range bin and not within the insect range bin triggers an increase in microwave alarm stage bin sensitivity to alarm upon detection of crawling intruders.

11. A method for minimizing false alarms due to small animals and insects in a coverage area of a microwave intrusion detector system, the method comprising:

providing a multistage microwave sensing system configured to transmit and receive microwave signals, the received microwave signals being indicative of a detected target, the multistage microwave sensing system including multiple range bins for classifying the received microwave signals, the multiple range bins including a microwave alarm stage bin to determine an alarm state of the microwave intrusion detector system;

providing a processor coupled to the multistage microwave sensing system;

determining a target range for a detected target from received microwave signals with the processor;

adjusting an alarm threshold of the microwave alarm stage bin with the processor based on the determined target range, wherein the alarm threshold is at a first level when the detected target is a short range target and second level when the target is a longer range target, such that the first level may be higher or lower than the second level depending on MW sensitivity in a short range and a long range and triggering an alarm based upon the alarm state indicating a security violation.

12. The method of claim 11, further comprising dynamically adjusting the microwave alarm stage bin sensitivity to a predetermined sensitivity upon determination of the target range.

13. The method of claim 11, further comprising determining whether to trigger an alarm based on the state of the microwave alarm stage bin.

14. The method of claim 11, wherein determining the target range comprises providing multiple range bins for the microwave sensing system.

15. The method of claim 14, further comprising providing an insect range bin capable of detecting insects in an immediate vicinity of the intrusion detector.

16. The method of claim 15, further comprising adjusting microwave alarm stage bin sensitivity to a low sensitivity when the insect range bin detects intrusion, such that the microwave alarm stage bin requires high amplitude pulses to trigger an alarm.

17. The method of claim 15, further comprising, when the insect range bin detects a target, triggering a time delay, beginning at insect range bin target detection, and terminating at some fixed time after clearance of the insect range bin, wherein alarm stage bin microwave signals are ignored during the time delay.

18. The method of claim 15, further comprising providing a short range bin for detection of crawling intruders under or in the near vicinity of the intrusion detector.

19. The method of claim 18, further comprising triggering an increase in microwave alarm stage bin sensitivity upon detection of a target within the short range bin and not within the insect range bin to facilitate detection of crawling intruders.

20. A method for improving false alarm immunity for a microwave intrusion detector, the method comprising:

providing a multistage microwave sensing system configured to transmit and receive microwave signals, the received microwave signals being indicative of a detected target, the multistage microwave sensing system including multiple range bins, the multiple range bins including a microwave alarm stage bin to determine an alarm state of the microwave intrusion detector system;

providing a processor coupled to the multistage microwave sensing system;

classifying a received microwave signal into a range bin with the processor;

estimating a target range based on a range bin state comparison;

determining an optimal microwave alarm stage bin sensitivity based on the estimated target range and triggering an alarm based upon the alarm state indicating a security violation.

21. The method of claim 20, further comprising dynamically adjusting the microwave alarm stage bin sensitivity level to a predetermined threshold upon determination of the target range.

22. The method of claim 20, further comprising providing an insect range bin capable of detecting insects in an immediate vicinity of the intrusion detector.

23. The method of claim 22, further comprising adjusting the microwave alarm stage bin threshold to a low sensitivity when the insect range bin detects intrusion, such that a microwave alarm trigger requires high amplitude pulses.

24. The method of claim 22, further comprising, when the insect range bin detects a target, triggering a time delay, beginning at insect range bin target detection, and terminating at some fixed time after clearance of the insect range bin, wherein alarm stage bin microwave signals are ignored during the time delay.

25. The method of claim 22, further comprising providing a short range bin for detection of crawling intruders under or in the near vicinity of the intrusion detector.

26. The method of claim 25, further comprising triggering an increase in microwave alarm stage bin sensitivity upon detection of a target within the short range bin and not within the insect range bin to facilitate detection of crawling intruders.

27. The method of claim 20, further comprising designating a long range bin covering the entire detector area as a microwave alarm stage bin.

28. The method of claim 27, further comprising adjusting long range bin sensitivity based on a sensitivity and object range function that is optimized for triggering an alarm based on human detection and avoiding alarms based on detection of insects and small animals.