Apparatus for finding the location of a car within a vast area

• US 4,673,921 A
• Filed: 07/19/1985
• Issued: 06/16/1987
• Est. Priority Date: 07/20/1984
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Saito, Muneo, Hayakawa, Shoichi
• Primary Examiner(s): Rowland, James L.
• Assistant Examiner(s): Swarthout, Brent A.
• Application Number:
  US06/756,825
• Time in Patent Office: 697 Days
• Field of Search: 340/988-991, 340/51, 340/539, 340/543, 340/63, 340/825.49, 340/825.54, 340/825.69, 340/825.72, 340/696, 340/52 R, 340/901, 340/933, 340/64, 455/345, 455/99, 455/92, 367/903, 367/99, 367/124, 180/167, 180/289, 180/287, 342/147, 342/456, 307/10 AT
• US Class Current: 340/539.32
• CPC Class Codes: G01S 3/38 using adjustment of real or effective orientation of directivity characteristic of an antenna or an antenna system to give a desired condition of signal derived from that antenna or antenna system, e.g. to give a maximum or minimum signal G01S3/16, G01S3/28 take precedence
• CPC Class Codes: G08G 1/123 indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, tramstransmission of navigation instructions to vehicles G08G1/0968

Abstract

A car-locating system comprises a portable transmitter-receiver unit and a car-mounted transmitter-receiver unit. The portable unit includes a switch, a first directional antenna, a first transmission section, a receiving section and a receipt level display. When it is closed, the switch generates a car-locating instruction. In response to this instruction, the first transmission section transmits a transmitting code through the directional antenna. Any signal received by the directional antenna is demodulated by the receiving section into a response code. The response code is compared with a first prescribed response code. When it is identical with the first prescribed response code, the receiving signal level is displayed by the receipt level display. The car-mounted unit includes a non-directional antenna, a second transmission section and a timer. The non-directional antenna receives the code transmitted from the portable unit. The code contained in the transmitted signal is compared with a transmitting code set in the car mounted unit. When it is identical with the transmitting code, the second transmission section is operated for the period of time set in the timer, thus transmitting a response signal containing a response code through the non-directional antenna.

Claims

1. An apparatus for finding the location of a car within a vast area, comprising a portable transmitter/receiver unit and a car-mounted transmitter/receiver unit,

said portable transmitter/receiver unit including:

first code-setting means for storing a particular transmitting code pertinent to the car;

fifth code-setting means for storing an instruction code;

a first switch for generating a car-locating instruction, when closed;

a second switch for generating an instruction to control a device which is provided in the car and which is desirably operated before the driver enters the car;

a first transmitting section for generating a transmission signal containing the transmitting code when said first switch is closed, and for generating a transmission signal containing the instruction code when said second switch is closed;

directional antenna means for transmitting any transmission signal generated by said first transmitting section, and for receiving a response signal containing a response code, from said car-mounted transmitter/receiver unit;

second code-setting means for storing a particular response code pertinent to the car;

a first receiving section for receiving the response code transmitted from said car-mounted transmitter/receiver unit, said first receiving section generating a signal having a level corresponding to the received level of the response signal, and detecting the response code contained in the response signal;

first collating means for collating the code contained in the signal received by said first receiving section, with the response code set in said second code setting means, and for generating a display instruction when the code contained in the signal received by said first receiving section coincides with the response code set in said second code setting means;

display-drive means, responsive to the display instruction from said first collating means, for generating a display-drive signal corresponding to the signal generated by said first receiving section; and

level-display means, responsive to the display-drive signal, for indicating the direction from said portable transmitter/receiver unit to the car when the maximum level of the signal generated by said first receiving section is indicated on the display

said car-mounted transmitter/receiver unit including;

non-directional antenna means;

a second receiving section for detecting a code of a signal received by and said non-directional antenna means;

third code-setting means for storing a code identical to the transmitting code set in said first code-setting means;

fourth code-setting means for storing a code identical to the response code set in said second code-setting means;

sixth code-setting means for storing a code identical to the instruction code set in said fifth code-setting means;

second collating means for collating the code detected by said second receiving section, with the code set in said third and sixth code-setting means, and for generating a first coincidence signal when the detected code coincides with the code set in said third code-setting means, and a second coincidence signal when the detected code coincides with the code set in said sixth code-setting means;

a second transmitting section, responsive to the first coincidence signal from said second collating means, for generating a response signal containing the response code set by said fourth code-setting means;

transmission power supply control means for supplying power to said second transmitting section for a prescribed period of time after said second collating means for generated the first coincidence signal;

response-code transmission means for transmitting the response signal generated by said second transmitting section, through said non-directional antenna means, when power is supplied to said second transmitting section; and

device-control means for controlling said device, in response to the second coincidence signal from said second collating means.

2. An apparatus according to claim 1, wherein said device control means controls a door lock mechanism of the car.

3. An apparatus according to claim 1, wherein said device control means controls an air conditioner installed in the car.

4. An apparatus according to claim 1, wherein said transmission power supply-control means includes a timer which is actuated when said second collating means detects that the code received by said second transmitting section is identical to the transmitting code, and wherein power is supplied to said second transmitting section for the period of time set in this timer.

5. An apparatus according to claim 1, wherein said directional antenna means includes an antenna element and a changeover switch connecting the antenna element to said first receiving section, said changeover switch being changed over and connected to said first transmitting section when said first or second switch is closed.

6. An apparatus according to claim 1, wherein said non-directional antenna means includes an antenna element and a changeover switch connecting the antenna element to said second received section, said changeover switch being changed over and connected to said second transmitting section when power is supplied to said second receiving section.

7. An apparatus according to claim 1, wherein said portable transmitter/receiver unit further includes a first power supply circuit for supplying power to said first transmitting section while said first or second switch is closed, and a second power supply circuit for supplying power to said first receiving section while said first or second switch is open.

8. An apparatus according to claim 7, wherein said second power supply circuit supplies power to said first receiving section for the period of time set by a timer after said first or second switch is opened.

9. An apparatus for finding the location of a car within a vast area, comprising a portable transmitter/receiver unit and a car-mounted transmitter/receiver unit,

said portable transmitter/receiver unit including:

first code-setting means for storing a particular transmitting code pertinent to the car;

a first switch for generating a car-locating instruction, when closed;

a first transmitting section for generating a transmission signal containing the transmitting code set in said first code-setting means, when said first switch is closed;

directional antenna means for transmitting the transmission signal generated by said first transmitting section, and for receiving a response signal containing a response code, from said car-mounted transmitter/receiver unit;

second code-setting means for storing a particular response code pertinent to the car;

seventh code-setting means for storing an alarm code;

a first receiving section for receiving the response signal transmitted from said car-mounted transmitter/receiver unit, said first receiving section generating a signal having a level corresponding to the received level of the response signal, and detecting the code contained in the response signal;

first collating means for collating the code detected from the signal received by said first receiving section, with the response code and the alarm code stored, respectively, in said second and seventh code-setting means, and for generating a first coincidence signal when the detected code coincides with said response code, and a third coincidence signal when the detected code coincides with said alarm code;

display-drive means, responsive to the first coincidence signal from said first collating means, for generating a display-drive signal corresponding to the signal generated by said first receiving section;

level-display means, responsive to the display-drive signal, for indicating the direction from said portable transmitter/receiver unit to the car when the maximum level of the signal generated by said first receiving station is indicated on the display;

alarm-producing means for producing an alarm when said first collating means generates the third coincidence signal;

said car-mounted transmitter/receiver unit including;

non-directional antenna means;

a second receiving section for detecting a code of a signal receiver by said non-directional antenna means;

third code-setting means for storing a code identical to the transmitting code set in said first code-setting means;

fourth code-setting means for storing a code identical to the response code set in said second code-setting means;

eighth code-setting means for storing a code identical to the alarm code set in said seventh code-setting means;

second collating means for collating the code detected by said second receiving section, with the transmission code set in said third code-setting means, and for generating a second coincidence signal when the code detected by said second receiving section coincides with the transmission code set in said third code-setting means;

trouble-sensing means including a sensor which detects the intrusion of an unauthorized person into the car, for generating an alarm signal in response to a signal generated by the sensor;

a second transmitting section for generating a response signal containing the response code set by said fourth code-setting means when the code received by said second receiving section is identical to the code set by said third code-setting means, and for generating a response signal containing the alarm code set by said eighth code-setting means when said trouble-sensing means generates the alarm signal;

transmission power supply control means for supplying power to said second transmitting section for a prescribed period of time when said second collating means generates the first coincidence signal, or when said trouble-sensing means generates the alarm signal; and

;

response-signal transmitting means for transmitting the response signal containing the response code or the alarm code, via said non-directional antenna means when power is supplied to said second transmitting section.

10. An apparatus according to claim 9, wherein said sensor of said trouble-sensing means comprises an ultrasonic sensor which detects the presence of an intruder in the car.

11. An apparatus according to claim 9, wherein said sensor of said trouble-sensing means comprises a sensor which detects the breaking of a window of the car.