Detecting system

• US 20030164790A1
• Filed: 08/28/2002
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kurita, Naoyuki, Kondoh, Hiroshi, Tsubota, Mikito
• Granted Patent: US 6,859,164 B2
• Time in Patent Office: Days
• US Class Current: 342/28
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/345 using triangular modulation
• CPC Class Codes: G01S 13/348 using square or rectangular modulation, e.g. diplex radar for ranging over short distances
• CPC Class Codes: G01S 13/75 using transponders powered from received waves, e.g. using passive transponders , or using passive reflectors
• CPC Class Codes: G01S 13/886 for alarm systems alarms with electrical actuation G08B13/22
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G01S 7/4021 of receivers
• CPC Class Codes: H01Q 15/14 Reflecting surfaces; Equivalent structures electromagnetic shields H01Q1/526

Abstract

In a position detecting system used to monitor a suspicious person and to give an alarm by using a radar which transmits/receives a microwave or a millimeterwave, the shape of a detectable area of the radar and that of the area to be monitored are not always equal to each other, and thus, an alarm may be erroneously given in response to the object outside the area to be monitored. For its solution, the area to be monitored is surrounded by a plurality of reflectors, and the coordinate values of the reflectors and the detecting object are calculated based on the signals reflected from the reflectors and the detecting object and then compared. When the coordinate value of the detecting object is inside the area to be monitored, it is determined that the detecting object is an intruding person or the like and an alarm is given. When the coordinate value of the detecting object is outside the area to be monitored, it is determined that the detecting object is not an intruding person or the like and no alarm is given. In addition, if the calibration and self diagnosis of the radar are periodically performed by using at least one of the reflectors, it is possible to maintain the performance of the radar in an optimal state.

Claims

1. A detecting system comprising:

a radar for detecting a detecting object;

a notification device for notifying the detection of the detecting object;

a signal processing unit for controlling the notification device based on the signal sent from the radar; and

a detecting area setting device for setting a range of the detecting area.

2. The detecting system according to claim 2,

wherein millimeterwave radar or microwave radar is used as the radar.

3. The detecting system according to claim 2,

wherein the detecting system can track movement of the detecting object.

4. The detecting system according to claim 3,

wherein the detecting area setting device is provided with a plurality of reflectors which are set on an outer periphery of the detecting area;

the detecting area is set by use of reflected signals from the reflectors; and

the notification device is set up to operate when the detecting object is inside the detecting area.

5. The detecting system according to claim 3,

wherein the signal processing unit has a memory means;

the detecting area setting device has a reflector;

the detecting area is set by storing signals obtained by moving the reflector along the outer periphery of the detecting area; and

the notification device is set up to operate when the detecting object is inside the detecting area.

6. The detecting system according to claim 4,

wherein the detecting system has a calibration means of the radar.

7. The detecting system according to claim 6,

wherein the calibration means performs an adjustment so as to reduce the difference between a distance to the reflector calculated based on a reflected signal from at least one of the reflectors and an actual distance to the reflector, thereby performing calibration of the radar.

8. The detecting system according to claim 6,

wherein the detecting system has a self-diagnosis means, and the self-diagnosis means functions to notify abnormality of the radar when intensity of the reflected signal from the reflector is reduced.

9. A detecting system comprising:

a millimeterwave or microwave radar for detecting a monitoring object;

an alarm device for notifying detection of the monitoring object;

a signal processing unit for processing a signal received by the radar and sending an operating signal to the alarm device; and

a monitoring area setting device for setting a monitoring area of the monitoring object,

wherein the signal processing unit controls the alarm device so as to give an alarm when the monitoring object exists inside the monitoring area and so as not to give an alarm when the monitoring object is outside the monitoring area.

10. The detecting system according to claim 9,

wherein the detecting system can monitor movement of the monitoring object.

11. The detecting system according to claim 10,

wherein the monitoring area setting device has a reflector, and the monitoring area is set by use of the reflected signal from the reflector.

12. The detecting system according to claim 10,

wherein the monitoring area setting device is provided with a plurality of reflectors set on the outer periphery of the monitoring area;

and the monitoring area is set by use of the reflected signal from the reflector.

13. The detecting system according to claim 10,

wherein the signal processing unit has a memory means;

the monitoring area setting device has a reflector; and

the monitoring area is set by accumulating the signal obtained by moving the reflector along the outer periphery of the monitoring area.

14. The detecting system according to claim 11,

wherein the detecting system has a calibration means of the radar;

and the calibration means functions to perform an adjustment so as to reduce the difference between a distance to the reflector calculated based on a reflected signal from the reflector and an actual distance to the reflector, thereby performing calibration of the radar.

15. The detecting system according to claim 11,

wherein the detecting system has a self-diagnosis means;

and the self-diagnosis means functions to notify abnormality of the radar when intensity of the reflected signal from the reflector is reduced.

16. The detecting system according to claim 11,

wherein the radar has two or more receiving antennas arranged in the horizontal direction and has two or more receivers connected to the receiving antennas;

and an angle to the monitoring object in the horizontal direction can be obtained based on the phase difference between the signals from the monitoring object received by the two or more receiving antennas.

17. The detecting system according to claim 11,

wherein the radar has a receiving antenna and a receiver;

and the radar also has a means for periodically changing directions of the receiving antenna and the transmitting antenna.

18. The detecting system according to claim 11,

wherein the radar detects a distance to the monitoring object and a relative speed by using the FMCW method.

19. The detecting system according to claim 11,

wherein the reflector is made of metal.