Detection of movable objects

• US 9,229,102 B1
• Filed: 08/08/2013
• Issued: 01/05/2016
• Est. Priority Date: 12/18/2009
• Status: Active Grant

• Current Assignee: L3harris Fuzing and Ordnance Systems Incorporated
• Original Assignee: L-3 Communications Security & Detection Systems, Inc. (Leidos Holdings, Inc.)
• Inventors: Wright, Donald Charles, Sentelle, Christopher Gary, May, Jeffery Carter, Hanna, Rafik, Voicu, Liviu
• Primary Examiner(s): Bythrow, Peter
• Application Number:
  US13/962,719
• Time in Patent Office: 880 Days
• Field of Search: 342/22, 342 94- 97, 342/175, 342/176, 342/179, 324332-341, 324/344, 324/602, 324/603, 324/637, 324/639, 324/641, 324/642, 324644-646, 324/658, 324/659
• US Class Current: 1/1
• CPC Class Codes: G01S 13/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• 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 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 7/4021 of receivers
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

Systems and methods for sensing targets on an opposite side of a wall are disclosed. In some aspects, the techniques include providing an indication to a user that portions of reflected radar signals were blocked by radiofrequency-blocking material at the wall. In some aspects, the techniques include identifying candidate targets as multipath echoes or motion-induced errors based on a correlation map.

Claims

1. A method for performing multi-hypothesis tracking of targets on an opposite side of a wall comprising:

transmitting, by one or more transmitters, a radar signal through a wall from a first side of the wall to a second side of the wall;

detecting, by one or more receivers, reflected portions of the radar signal;

processing, by a signal processor, the reflected portions of the radar signal to obtain a set of measurements;

filtering, by a filter, the set of measurements to obtain a first subset of measurements associated with moving targets and a second subset of measurements associated with stationary or near-stationary targets;

for each measurement in the first subset of measurements and the second subset of measurements;

determining, by a track processing system, a set of hypotheses, the set of hypotheses including;

i) classifying the respective measurement as clutter, ii) associating the respective measurement with an existing target, or iii) initializing a new target with the respective measurement; and

selecting, by the track processing system, the hypothesis from the set of hypotheses having a highest likelihood;

determining, by the track processing system, a first set of tracks for one or more moving targets based on the selected hypotheses from the first subset of measurements, the first set of tracks comprising a position and velocity estimate for each of the one or more moving targets; and

determining, by the track processing system, a second set of tracks for one or more stationary or near-stationary targets based on the selected hypotheses from the second subset of measurements, the second set of tracks comprising a position estimate for each of the one or more stationary or near-stationary targets.

2. The method of claim 1, wherein the set of hypotheses for each measurement further includes classifying the respective measurement as a multipath reflection of an existing target.

3. The method of claim 1, further comprising merging a track from the first set of tracks with another track from the second set of tracks.

4. The method of claim 1, further comprising updating the first set of tracks and the second set of tracks based on a new set of measurements.

5. A system comprising:

one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising;

transmitting, by one or more transmitters, a radar signal through a wall from a first side of the wall to a second side of the wall;

detecting, by one or more receivers, reflected portions of the radar signal;

processing, by a signal processor, the reflected portions of the radar signal to obtain a set of measurements;

filtering, by a filter, the set of measurements to obtain a first subset of measurements associated with moving targets and a second subset of measurements associated with stationary or near-stationary targets;

for each measurement in the first subset of measurements and the second subset of measurements;

determining, by a track processing system, a set of hypotheses, the set of hypotheses including;

i) classifying the respective measurement as clutter, ii) associating the respective measurement with an existing target, or iii) initializing a new target with the respective measurement; and

selecting, by the track processing system, the hypothesis from the set of hypotheses having a highest likelihood;

determining, by the track processing system, a first set of tracks for one or more moving targets based on the selected hypotheses from the first subset of measurements, the first set of tracks comprising a position and velocity estimate for each of the one or more moving targets; and

determining, by the track processing system, a second set of tracks for one or more stationary or near-stationary targets based on the selected hypotheses from the second subset of measurements, the second set of tracks comprising a position estimate for each of the one or more stationary or near-stationary targets.

6. The system of claim 5, wherein the set of hypotheses for each measurement further includes classifying the respective measurement as a multipath reflection of an existing target.

7. The system of claim 5, the operations further comprising merging a track from the first set of tracks with another track from the second set of tracks.

8. The system of claim 5, the operations further comprising updating the first set of tracks and the second set of tracks based on a new set of measurements.

9. A non-transitory computer-readable medium storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:

transmitting, by one or more transmitters, a radar signal through a wall from a first side of the wall to a second side of the wall;

detecting, by one or more receivers, reflected portions of the radar signal;

processing, by a signal processor, the reflected portions of the radar signal to obtain a set of measurements;

filtering, by a filter, the set of measurements to obtain a first subset of measurements associated with moving targets and a second subset of measurements associated with stationary or near-stationary targets;

for each measurement in the first subset of measurements and the second subset of measurements;

determining, by a track processing system, a set of hypotheses, the set of hypotheses including;

i) classifying the respective measurement as clutter, ii) associating the respective measurement with an existing target, or iii) initializing a new target with the respective measurement; and

selecting, by the track processing system, the hypothesis from the set of hypotheses having a highest likelihood;

determining, by the track processing system, a first set of tracks for one or more moving targets based on the selected hypotheses from the first subset of measurements, the first set of tracks comprising a position and velocity estimate for each of the one or more moving targets; and

determining, by the track processing system, a second set of tracks for one or more stationary or near-stationary targets based on the selected hypotheses from the second subset of measurements, the second set of tracks comprising a position estimate for each of the one or more stationary or near-stationary targets.

10. The medium of claim 9, wherein the set of hypotheses for each measurement further includes classifying the respective measurement as a multipath reflection of an existing target.

11. The medium of claim 9, the operations further comprising merging a track from the first set of tracks with another track from the second set of tracks.

12. The medium of claim 9, the operations further comprising updating the first set of tracks and the second set of tracks based on a new set of measurements.