Real-time method for establishing a detection map for a network of sensors

• US 8,265,870 B1
• Filed: 01/20/2010
• Issued: 09/11/2012
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Koch, Mark W., Nguyen, Hung D., Giron, Casey, Rondeau, Daniel M., Russell, John L.
• Primary Examiner(s): EL CHANTI, HUSSEIN A
• Application Number:
  US12/690,630
• Time in Patent Office: 965 Days
• Field of Search: 701/450
• US Class Current: 701/450
• CPC Class Codes: G01V 1/24 Recording seismic data

Abstract

A method for establishing a detection map of a dynamically configurable sensor network. This method determines an appropriate set of locations for a plurality of sensor units of a sensor network and establishes a detection map for the network of sensors while the network is being set up; the detection map includes the effects of the local terrain and individual sensor performance. Sensor performance is characterized during the placement of the sensor units, which enables dynamic adjustment or reconfiguration of the placement of individual elements of the sensor network during network set-up to accommodate variations in local terrain and individual sensor performance. The reconfiguration of the network during initial set-up to accommodate deviations from idealized individual sensor detection zones improves the effectiveness of the sensor network in detecting activities at a detection perimeter and can provide the desired sensor coverage of an area while minimizing unintentional gaps in coverage.

Claims

1. A method for establishing a detection map of a dynamically configurable sensor network, the method comprising:

defining an initial perimeter;

deriving from the initial perimeter an initial placement map for a plurality of sensor units, the initial placement map comprising a plurality of initial placement sites for sensor units, wherein each sensor unit has an expected detection zone around the sensor unit'"'"'s initial placement site and wherein a combination of the expected detection zones forms a detection map corresponding to a detection perimeter;

positioning a first sensor unit using a mobile deployment unit equipped with a location-identification means at a first actual placement site proximate to a first initial placement site and incorporating a location of the first sensor unit into the detection map;

determining a first measured detection zone of the first sensor unit at least in part by detecting an activity of the mobile deployment unit;

modifying the detection map by replacing in the detection map the expected detection zone of the first sensor unit with the first measured detection zone;

positioning a second sensor unit using the mobile deployment unit at a second actual placement site proximate to an adjacent initial placement site and incorporating a location of the second sensor unit into the detection map;

determining a second measured detection zone of the second sensor unit at least in part by detecting the activity of the mobile deployment unit;

replacing a second expected detection zone of the second sensor unit with the second measured detection zone in the detection map;

determining whether a region of the detection map corresponding to a region between the first and second sensor units provides a minimum probability of detection within the region between the first and second sensor units;

if the minimum probability of detection is not provided, repositioning the second sensor unit using the mobile deployment unit, redetermining the second measured detection zone of the second sensor unit at least in part by detecting the activity of the mobile deployment unit to obtain a replacement second measured detection zone, replacing the second measured detection zone with the replacement second measured detection zone in the detection map, and determining whether the region of the detection map corresponding to the region between the first and second sensor units provides a minimum probability of detection within the region between the first and second sensor units;

if the minimum probability of detection is provided, positioning a third sensor unit using the mobile deployment unit at a third actual placement site proximate to a next adjacent initial placement site, determining a third measured detection zone of the third sensor unit at least in part by detecting the activity of the mobile deployment unit, and replacing a third expected detection zone with the third measured detection zone in the detection map; and

repeating the steps of positioning sensor units, determining measured detection zones, replacing expected detection zones with measured detection zones in the detection map, determining provision of the minimum probability of detection between adjacent sensor units, and optionally repositioning sensor units until the detection map comprising measured detection zones of the detection perimeter of the dynamically configurable sensor network has been established.

2. The method of claim 1, wherein detecting an activity of the mobile deployment unit using the first sensor unit comprises:

obtaining sensor data from the first sensor unit at a measurement time;

determining whether the sensor data indicates a detection of the activity of the mobile deployment unit by the first sensor unit;

determining a signal-generating location of the mobile deployment unit at the measurement time; and

incorporating the signal-generating location into the detection map as part of the first measured detection zone.

3. The method of claim 1, further comprising:

determining a location for the actual placement site of the sensor unit using the location-identification means of the mobile deployment unit or using a location-identification means associated with the sensor unit; and

communicating the location of the actual placement site to a base unit for incorporation into the detection map.

4. The method of claim 3, further comprising:

determining whether the actual placement site is an acceptable placement site and instructing the MDU to reposition the sensor unit if the actual placement site is not one of the acceptable placement sites.

5. The method of claim 3, wherein the location-identification means employs a method of retrieving GNSS data or a pulsed triangulation method.

6. The method of claim 3, wherein the base unit comprises a computer, a means for establishing communication with the sensor unit, and optionally a location-identification means.

7. The method of claim 6, wherein the base unit is co-located with the mobile deployment unit.

8. The method of claim 6, wherein the base unit performs at least one of the steps of:

determining a location of the initial placement site wherein the location is proximate to the detection perimeter;

determining whether the actual placement site is one of the acceptable placement sites;

analyzing a combination of actual placement sites and unoccupied initial placement sites to determine if the detection perimeter will encompass a desired region and directing relocation of at least one of a site selected from the actual placement sites and an unoccupied initial placement site if the detection perimeter does not encompass the desired region; and

determining whether an overlap of adjacent measured detection zones provides the minimum probability of detection at a corresponding portion of the detection perimeter.

9. The method of claim 1, wherein the mobile deployment unit is a living being or a robotic device.

10. The method of claim 1, wherein the location-identification means is a differential GPS unit.

11. The method of claim 1, further comprising:

deriving a modified placement map comprising actual placement sites and unoccupied initial placement sites, wherein at least one of the unoccupied initial placement sites is moved to produce a combination of detection zones that provides a better probability of detection along at least part of the detection perimeter, and

replacing the initial placement map with the modified placement map for guiding placement of sensor units.

12. The method of claim 1, further comprising combining measured detection zones of at least two proximate sensor units to form a combined detection zone for including in the detection map for determining whether a region of the detection map provides the minimum probability of detection.

13. The method of claim 1, wherein the sensor unit comprises at least two sensing modalities and further comprising:

determining a modality detection zone for each sensing modality; and

determining the measured detection zone of the sensor unit by combining the modality detection zones.

14. The method of claim 13, wherein providing the minimum probability of detection is provided by exceeding a modality minimum probability of detection for the at least two sensing modalities.

15. The method of claim 1, wherein the sensor unit comprises at least one sensor selected from the group consisting of a seismic sensor, an acoustic sensor, an optical sensor, a chemical sensor, and a radiation sensor.

16. The method of claim 1, wherein the detection perimeter is discontinuous.

17. The method of claim 1, wherein the expected detection zone corresponds to a region around the initial placement site where a value of a sensor probability of detection function equals or exceeds an initial minimum probability of detection.

18. The method of claim 1, wherein the step of determining each measured detection zone is performed by a corresponding sensor unit.

19. The method of claim 1, wherein the measured detection zone is at least partially measured and partially calculated using a sensor probability of detection function.

20. A method for establishing a detection map of a dynamically configurable sensor network, the method comprising:

determining a first measured detection zone of a first sensor unit of a sensor network at least in part by detecting an activity of a mobile deployment unit equipped with a location-identification means, wherein the sensor network comprises a plurality of sensor units that form a detection perimeter by combining a plurality of detection zones, wherein each sensor unit has a sensor placement site and a presumed detection zone, wherein a combination of the presumed detection zones forms a detection map;

modifying the detection map by replacing in the detection map the presumed detection zone of the first sensor unit with the first measured detection zone;

determining a second measured detection zone of a second sensor unit proximate to the first sensor unit at least in part by detecting the activity of the mobile deployment unit;

replacing the presumed detection zone of the second sensor unit with the second measured detection zone in the detection map;

determining whether a region of the detection map corresponding to the region between the first and second sensor units provides a minimum probability of detection within the region between the first and second sensor units;

if the minimum probability of detection is not provided, repositioning the second sensor unit to a replacement second sensor placement site using the mobile deployment unit, redetermining the second measured detection zone of the second sensor unit at least in part by detecting the activity of the mobile deployment unit to obtain a replacement second measured detection zone, replacing the second measured detection zone with the replacement second measured detection zone in the detection map, and determining whether the region of the detection map corresponding to the region between the first and second sensor units provides the minimum probability of detection within the region between the first and second sensor units;

if the minimum probability of detection is provided, determining a third measured detection zone of a third sensor unit at least in part by detecting the activity of the mobile deployment unit, and replacing a third presumed detection zone of the third sensor unit with the third measured detection zone in the detection map; and

repeating the steps of determining measured detection zones, replacing corresponding presumed detection zones with measured detection zones in the detection map, determining provision of the minimum probability of detection between adjacent sensor units, and optionally repositioning sensor units until the detection map comprising measured detection zones of the sensor network has been established.