METHOD AND SYSTEM FOR PRESENCE DETECTION

• US 20090102697A1
• Filed: 10/20/2008
• Published: 04/23/2009
• 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: Antonsson, Anders
• Granted Patent: US 7,760,130 B2
• Time in Patent Office: Days
• US Class Current: 342/27
• 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

Abstract

A method for presence detection using a microwave transmitter and a microwave receiver, the method including generating a sequence of clock pulses by means of a pulse generator, feeding the clock pulses to a clocked circuit arranged to generate a sequence of first pulses of a first pulse length and a sequence of second pulses of a second pulse length, each one of the first and second pulse lengths being related to a predetermined number of the clock pulses, periodically actuating the microwave transmitter by means of the sequence of first pulses, periodically actuating the microwave receiver by means of the sequence of second pulses; and determining whether an object is present in the detection volume based on microwave radiation being received by the microwave receiver. A system for such presence detection is also disclosed.

Claims

1. A method for presence detection within a predetermined detection volume using a microwave transmitter and a microwave receiver, the method comprising:

generating a sequence of clock pulses with a pulse generator;

transmitting the clock pulses to a clocked circuit arranged to generate a sequence of first pulses of a predetermined first pulse length and a sequence of second pulses of a predetermined second pulse length, each one of the first and second pulse lengths being related to a predetermined number of the clock pulses;

periodically actuating the microwave transmitter with the sequence of first pulses;

periodically actuating the microwave receiver with the sequence of second pulses; and

determining whether an object is present in the detection volume based on microwave radiation being received by the microwave receiver.

2. The method according to claim 1 wherein the first pulses constitute transmit enable signals for the microwave transmitter, and the second pulses constitute receive enable signals for the microwave receiver.

3. The method according to claim 2 wherein each receive enable signal is generated slightly delayed after each of the transmit enable signal.

4. The method according to claim 1 wherein the clocked circuit is controlled by a microcontroller to determine the relation between the predetermined number of clock pulses fed to the clocked circuit and the first and second pulse lengths.

5. A system for presence detection within a predetermined detection volume, the system comprising:

a pulse generator for generating a sequence of clock pulses;

a clocked circuit receiving the sequence of clock pulses and generating a sequence of first pulses of a predetermined first pulse length and a sequence of second pulses of a predetermined second pulse length, the first and second pulse lengths being related to a predetermined number of the clock pulses;

means for periodically actuating a microwave transmitter; and

a microwave receiver for detecting microwave radiation within the detection volume and for determining whether an object is present in the detection volume based on the microwave radiation being received.

6. The system according to claim 5 further comprising a microcontroller arranged for controlling the clocked circuit by determining the relation between the number of clock pulses fed to the clocked circuit and the first and second pulse lengths.

7. The system according to claim 5 wherein the means for periodically actuating the microwave transmitter comprises a first pulse generator arranged for producing a sequence of pulses enabling the pulse generator to generate the sequence of clock pulses.

8. A system for presence detection within a predetermined detection volume, the system comprising:

a first pulse generator producing a low frequency pulse sequence;

a second pulse generator enabled by the low frequency pulse sequence to produce a high frequency pulse sequence;

a clocked circuit enabled by the high frequency pulse sequence to generate a sequence of transmit enable pulses and a sequence of receive enable pulses, the transmit enable pulses having a first pulse length related to a first number of pulses in the high frequency pulse sequence and the receive enable pulses having a second pulse length related to a second number of pulses in the high frequency pulse sequence;

a transmitter receiving the transmit enable pulses and actuated thereby to enter an active transmit state wherein the transmitter transmits microwave radiation; and

a receiver actuated by the receive enable pulses to enter an active receive mode wherein the receiver detects the microwave radiation within transmitted by the transmitter, the receiver operable to determine whether an object is present in the detection volume based on the microwave radiation being received.

9. The system according to claim 8 further comprising a microcontroller controlling the clocked circuit by determining a relation between the number of clock pulses fed to the clocked circuit and the first and second pulse lengths.