Intrusion detection and tracking system

• US 8,836,344 B2
• Filed: 07/22/2011
• Issued: 09/16/2014
• Est. Priority Date: 07/27/2010
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Habib, Toni S., Habib, Wassim S., Lung, Teh-Kuang
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): HOQUE, FARHANA AKHTER
• Application Number:
  US13/188,596
• Publication Number:
  US 20120025849A1
• Time in Patent Office: 1,152 Days
• Field of Search: 324/647, 324/616, 340/567, 342/126, 455/404.2
• US Class Current: 324/647
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

In one aspect, a method to detect an object in an area includes forming a wireless network among a plurality of nodes, each of the nodes being configured to generate an electromagnetic field (EMF) in the area and determining changes in the EMF between two nodes based on: a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value, a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and a third difference in link quality values between a previously determined link quality value and a currently determined link quality value. The method further comprises detecting the object based on the changes in the EMF.

Claims

1. A method to detect an object in an area, comprising:

forming a wireless network among a plurality of nodes, each of the nodes being configured to generate an electromagnetic field (EMF) in the area;

determining changes in the EMF between two nodes based on;

a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value,

a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and

a third difference in link quality values between a previously determined link quality value and a currently determined link quality value; and

detecting the object based on the changes in the EMF;

wherein the received signal strength values and link quality values are values in a frame formatted and transmitted in accordance with a communications protocol.

2. The method of claim 1 wherein the first difference in received signal strength values comprises a difference in received signal strength indicator (RSSI) values between a previously determined RSSI value and a currently determined RSSI value,

wherein the second difference in received signal strength values comprises a difference in RSSI values between the currently determined RSSI value and an average RSSI value, and

wherein the third difference in link quality values comprises a difference in link quality indicator (LQI) values between a previously determined LQI value and a currently determined LQI value.

3. The method of claim 1 wherein determining changes in the EMF comprises determining a measurement value (MV) at a first node based on a signal received at the first node from a second node, the MV being equal to:

|kΔ

₁|+|lΔ

₂|+|mΔ

₃|,

where, k, l and m are constants, Δ

₁ is the first difference in received signal strength values, Δ

₂ is the second difference in received signal strength values and Δ

₃ is the third difference in link quality values.

4. The method of claim 3, further comprising transmitting the measurement value from the first node to an access point if the measurement value is above a measurement value threshold.

5. The method of claim 4, further comprising transmitting a detection from the access point to a controller if a number of measurement values received at the access point in a cycle exceeds a detection threshold.

6. The method of claim 5 wherein transmitting a detection comprises transmitting a detection of one of a human, a vehicle and an airplane.

7. The method of claim 5, further comprising tracking the object at the controller in response to detections received from the access point.

8. The method of claim 1, further comprising disposing the plurality of nodes throughout a building.

9. The method of claim 1, further comprising disposing a first node on a first building and disposing a second node on a second building.

10. The method of claim 1, further comprising correlating the object detected by determining changes in the EMF with a detection by the sensor.

11. The method of claim 10 wherein correlating the object detected by determining changes in the EMF with a detection by the sensor comprises correlating the object detected by analyzing changes in the EMF with a detection by a chemical, radiological, biological, and nuclear (CRBN), explosives, and/or firearm materials (CBRNE) sensor.

12. The method of claim 1, further comprising:

receiving, at one or more of the plurality of nodes, data from a beacon; and

correlating the object detected with the data from the beacon.

13. The method of claim 12 wherein receiving data from the beacon comprises receiving at least one of a beacon ID and vital data collected by a wearer of the beacon.

14. The method of claim 13 wherein the vital data comprises body temperature, heart rate, oxygen supply level, surrounding hazardous fumes, and/or gasses measured by sensors integrated into the beacon.

15. A system to detect an object in an area comprising;

a plurality of nodes, each node comprising at least one processor and configured to generate an electromagnetic field (EMF) in the area;

wherein each node is configured to determine changes in the EMF between two nodes based on a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value, a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and a third difference in link quality values between a previously determined link quality value and a currently determined link quality value, wherein the system detects an object based on changes in the EMF;

wherein the received signal strength values and link quality values are values in a frame formatted and transmitted in accordance with a communications protocol.

16. The system of claim 15 wherein the first difference in received signal strength values comprises a difference in received signal strength indicator (RSSI) values between a previously determined RSSI value and a currently determined RSSI value,

wherein the second difference in received signal strength values comprises a difference in RSSI values between the currently determined RSSI value and an average RSSI value, and

wherein the third difference in link quality values comprises a difference in link quality indicator (LQI) values between a previously determined LQI value and a currently determined LQI value.

17. The system of claim 15 wherein determining changes in the EMF comprises determining a measurement value (MV) at a first node based on a signal received at the first node transmitted by a second node, the MV being equal to:

|kΔ

₁|+|lΔ

₂|+|mΔ

₃|,

where, k, l and m are constants, Δ

₁ is the first difference in received signal strength values, Δ

₂ is the second difference in received signal strength values and Δ

₃ is the third difference in link quality values.

18. The system of claim 17, further comprising an access point,

wherein each node is further configured to transmit the measurement value from the first node to the access point if the measurement value is above a measurement value threshold,

wherein the access point is configured to transmit a detection of an object to a controller if a number of measurement values received at the access point in a cycle exceeds a detection value threshold, and

wherein the controller is configured to track the object in response to detections received from the access point.

19. The system of claim 15, further comprising a controller configured to correlate an object detected with a detection from the sensor,

wherein the sensor is a chemical, radiological, biological, and nuclear (CRBN), explosives, and/or firearm materials (CBRNE) sensor.

20. The system of claim 15, further comprising a controller configured to correlate an object detected with data from a beacon,

wherein the data from the beacon comprises at least one of a beacon ID and vital data collected by a wearer of the beacon, and

wherein the vital data comprises body temperature, heart rate, oxygen supply level, surrounding hazardous fumes and/or gasses measured by sensors integrated into the beacon.

21. An article comprising:

a non-transitory machine-readable medium that stores executable instructions to detect an object, the instructions causing a machine to;

determine changes in the EMF between two nodes based on a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value, a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and a third difference in link quality values between a previously determined link quality value and a currently determined link quality value;

wherein the received signal strength values and link quality values are values in a frame formatted and transmitted in accordance with a communications protocol.

22. The article of claim 21 wherein the instructions causing the machine to determine changes in the EMF comprises instructions causing a machine to determine a measurement value (MV) at a first node based on a signal received at the first node from a second node, the MV being equal to:

|kΔ

₁|+|lΔ

₂|+|mΔ

₃|,

where, k, l and m are constants, Δ

₁ is the first difference in received signal strength values, Δ

₂ is the second difference in received signal strength values and Δ

₃ is the third difference in link quality values.

23. The article of claim 21 wherein the first difference in received signal strength values comprises a difference in received signal strength indicator (RSSI) values between a previously determined RSSI value and a currently determined RSSI value,

wherein the second difference in received signal strength values comprises a difference in RSSI values between the currently determined RSSI value and an average RSSI value, and

wherein the third difference in link quality values comprises a difference in link quality indicator (LQI) values between a previously determined LQI value and a currently determined LQI value.