METHOD AND SYSTEM FOR PRESENCE DETECTION

• US 20090167590A1
• Filed: 10/17/2008
• Published: 07/02/2009
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Svedoff, Goran, Antonsson, Anders
• Granted Patent: US 7,907,082 B2
• Time in Patent Office: Days
• US Class Current: 342/28
• CPC Class Codes: G01S 13/14 wherein a voltage or current pulse is initiated and terminated in accordance respectively with the pulse transmission and echo reception
• CPC Class Codes: G01S 13/18 wherein range gates are used
• 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 7/282 Transmitters
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period

Abstract

A method and system for presence detection within a detection volume delimited by an inner radius and an outer radius using microwave radiation. The outer radius of the detection volume is controlled by selecting the length of a first pulse controlling the transmit interval of a microwave transmitter and by selecting the length of a third pulse controlling the receive interval of a microwave receiver. The inner radius of the detection volume is controlled through selecting the length of a second pulse defining a predetermined time period between the first pulse and the third pulse.

Claims

1. A method for presence detection within a detection volume delimited by an inner radius and an outer radius from a center of said detection volume, said method comprising:

transmitting microwaves from said center of said detection volume by means of a microwave transmitter;

detecting microwave radiation reflected towards said center of said detection volume by means of a microwave receiver; and

determining the presence of a moving object within said detection volume based on properties of the microwave radiation being received by said microwave receiver;

wherein said outer radius of said detection volume is controlled through selecting a length of a first pulse controlling a transmission interval of said microwave transmitter and through selecting a length of a third pulse controlling a reception interval of said microwave receiver; and

wherein said inner radius of said detection volume is controlled through selecting a length of a second pulse defining a predetermined time period pause between said first pulse and said third pulse.

2. The method according to claim 1, wherein it comprises:

controlling said microwave transmitter to transmit a sequence of first pulses each having a first pulse length and being generated by means of a first pulse generator;

controlling said microwave receiver to detect said reflected microwave radiation by means of a sequence of third pulses each having a third pulse length and being generated by means of a third pulse generator; and

controlling said third pulse generator to produce each said third pulse said predetermined time period after each said first pulse.

3. The method according to claim 1 wherein the step of determining the presence of a moving object within said detection volume comprises using a Doppler motion sensor process.

4. The method according to claim 3 wherein it comprises:

controlling the length of said first pulses by means of a first pulse length detector; and

controlling the length of said third pulses by means of a third pulse length detector.

5. The method according to claim 4 wherein it comprises:

providing a measurement by said first pulse length detector which is fed to a first comparator which is controlled with a first target pulse length ; and

providing a measurement by said third pulse length detector which is fed to a third comparator which is controlled with a third target pulse length.

6. The method according to claim 2 wherein it comprises:

defining said predetermined time period by means of a second pulse length generator which is connected to be triggered by said first pulse generator and connected to trigger said third pulse generator.

7. A system for presence control within a detection volume delimited by an inner radius and an outer radius from a center of said detection volume, said system comprising:

a microwave-based transmitting and receiving unit for transmitting microwaves from said center of said detection volume by means of a microwave transmitter and detecting microwave radiation reflected towards said center of said detection volume by means of a microwave receiver and,

means for determining the presence of a moving object within said detection volume based on the properties of the microwave radiation being received by said microwave receiver;

means for controlling said outer radius of said detection volume through selecting the length of a first pulse controlling said microwave transmitter to transmit said microwaves and through selecting the length of a third pulse controlling said microwave receiver to detect said microwave radiation reflected towards said center of said detection volume; and

means for controlling said inner radius of said detection volume through selecting the length of a second pulse for defining a predetermined time period pause between said first pulse and said third pulse.

8. The system according to claim 7 further comprising:

means for controlling said microwave transmitter to transmit said microwaves by means of a sequence of first pulses each having a predetermined first pulse length and being generated by a first pulse generator;

means for controlling said microwave receiver to detect said reflected microwave radiation by means of a sequence of third pulses each having a predetermined pulse length and being generated by a third pulse generator; and

means for controlling said third pulse generator to produce each said third pulse said predetermined time period after each said first pulse.

9. A system for presence control within a detection volume delimited by an inner radius and an outer radius from a center of said detection volume, said system comprising:

a microwave transmitter for transmitting microwaves from said center of said detection volume;

a microwave receiver for detecting microwave radiation reflected towards said center of said detection volume;

a first pulse generator generating a first pulse establishing a transmit interval of said microwave transmitter;

a third pulse generator generating a third pulse establishing a receive interval of said microwave receiver; and

a second pulse generator generating a second pulse defining a predetermined time period pause between said first pulse and said third pulse.