SYSTEMS AND METHODS FOR DETECTION OF OCCUPANCY USING RADIO WAVES

• US 20170123058A1
• Filed: 11/04/2016
• Published: 05/04/2017
• Est. Priority Date: 11/04/2015
• Status: Active Grant

• Current Assignee: University of Hawai'i
• Original Assignee: University of Hawai'i
• Inventors: Boric-Lubecke, Olga, Yamada, Shuhei, Yavari, Ehsan, Gao, Xiaomeng, Song, Chenyan, Nuti, Pooja
• Granted Patent: US 10,620,307 B2
• Time in Patent Office: Days
• 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 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder

Abstract

Systems and methods are disclosed for detecting a presence of a person in an area of coverage using radar. A transmitter can transmit radio signals in a first direction in an area of coverage defined by a wall and a floor. A receiver can receive the transmitted radio signals reflected back from the area of coverage. A signal conditioning circuit can process the received radio signals. One or more hardware processors can be programmed to analyze the processed radio signals and detect a presence of a person in the area of coverage based on the analysis. The analysis of the processed signals can be performed in both time and frequency domain. In addition to radar, an input from an infrared sensor can also be used in conjunction with radar based detection.

Claims

1. A sensor configured to detect a presence of a person in an area of coverage using radio waves, the sensor comprising:

a transmitter configured to transmit radio signals in an area of coverage and in a first direction which is at an angle from a plane parallel to a floor of the area of coverage, the angle is greater than 0;

a receiver configured to receive the transmitted radio signals reflected back from the area of coverage;

a signal conditioning circuit configured to process the received radio signals; and

one or more hardware processors configured to analyze the processed radio signals and detect a presence of a person in the area of coverage based on the analysis.

2. The sensor of claim 1, wherein the one or more hardware processors are further configured to:

determine a moving average corresponding to amplitude of the received signal;

compare the moving average to a first threshold; and

control an operation of an electronic system based on the comparison of the moving average to the first threshold.

3. The sensor of claim 2, wherein the one or more hardware processors are further configured to:

extract a first rate of a physiological parameter from a first frequency range of a frequency transform of the received signal;

determine a deviation of the first rate from an expected rate of the physiological parameter; and

control the operation of the electronic system based on the determination of the deviation.

4. The sensor of claim 3, wherein the one or more hardware processors are further configured to:

determine a ratio in a time period that the moving average is greater than the first threshold; and

control the operation of the electronic system based on the determined ratio.

5. The sensor of claim 4, wherein the one or more hardware processors are further configured to:

extract a second rate of a physiological parameter from a second frequency range of the frequency transform of the received signal, the second frequency range corresponding to a harmonic of the first frequency;

determine a harmonic deviation of the second rate from a harmonic expected rate of the physiological parameter; and

compare the deviation of the first rate from the expected rate and the harmonic deviation of the second rate from the harmonic expected rate;

control the operation of the electronic system based on the comparison of the deviation of the first rate and the harmonic deviation.

6. The sensor of claim 1, wherein the one or more hardware processors are further configured to:

receive an indication from an infrared sensor; and

control the transmitter based on the received indication from the infrared sensor.

7. The sensor of claim 1, wherein the angle is substantially 45 degrees.

8. The sensor of claim 1, further comprising an antenna.

9. The sensor of claim 8, wherein the antenna is shared by the transmitter and the receiver.

10. The sensor of claim 8, wherein the antenna is mounted to a chassis of the sensor to transmit the radio signals in the first direction.

11. The sensor of claim 1, wherein the first direction is not in a plane parallel to the floor.

12. The sensor of claim 1, wherein the first direction is not substantially perpendicular to a surface parallel to a wall.

13. The sensor of claim 1, further comprising an infrared sensor configured to detect motion.

14. The sensor of claim 1, wherein the one or more hardware processors are further configured to control an operation of an electronic system based on the detecting a presence of the person.

15. A method for detecting a presence of a person in an area of coverage using radio waves, the method comprising:

transmitting a radio wave in a first direction in an area of coverage;

receiving the transmitted radio wave from the area of coverage;

extracting a time domain feature from the received radio wave;

extracting a frequency domain feature from the received radio wave; and

detecting a presence of a person in an area of coverage based on the extracted time domain feature and the frequency domain feature.

16. The method of claim 15, wherein the time domain feature comprises an average measurement of an amplitude of the signal.

17. The method of claim 15, wherein the frequency domain feature comprises a peak in a first frequency range corresponding to a physiological rate.

18. The method of claim 15, further comprising controlling an electronic system based on the detection.

19. A sensor configured to detect a presence of a person in an area of coverage using radio waves, the sensor comprising:

a transmitter configured to transmit radio signals in an area of coverage and in a first direction;

a receiver configured to receive the transmitted radio signals reflected back from the area of coverage; and

one or more hardware processors configured to receive an input from a second sensor and control an operation of the transmitter based on the received input from the second sensor.

20. The sensor of claim 19, wherein the second sensor comprises at least one of an infrared sensor and an ultrasonic sensor.