Portable unit locating system and method

• US 20070030165A1
• Filed: 07/12/2006
• Published: 02/08/2007
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Teshima, Kentaro, Nakashima, Kazuhiro, Tsuzuki, Haruyuki
• Granted Patent: US 7,429,922 B2
• Time in Patent Office: Days
• US Class Current: 340/825.490
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: G07C 2209/63 Comprising locating means for detecting the position of the data carrier, i.e. within the vehicle or within a certain distance from the vehicle
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A portable unit locating system is incorporated in a vehicle equipment control system including a portable unit and an in-vehicle unit, which communicate each other for controlling vehicle equipment such as doors. The in-vehicle unit includes inside transmitters, a receiver, a comparison ECU and a display. The transmitters transmit respective request signals in a vehicle compartment. The comparison ECU determines whether any response signal has been received from the portable unit in response the request signals, while gradually varying output levels of the request signals. The comparison ECU then specifies a location of the portable unit based on a change in determination results. The display visually or audibly notifies the specified location of the portable unit to a vehicle user.

Claims

1. A system that allows two-way communication between a portable unit and an in-vehicle unit in a manner that the portable unit transmits a response signal including an ID code in response to a request signal transmitted from the in-vehicle unit, so that the in-vehicle unit receives the response signal from the portable unit, performs a comparison between the ID code included in the response signal and a pre-registered code, and controls vehicle equipment in accordance with a comparison result, wherein the in-vehicle unit comprises:

transmitter means that transmits the request signal in a vehicle compartment; and

receiver means that receives the response signal from the portable unit, characterized by further comprising;

output varying means for varying an output level of the request signal transmitted from the transmitter means;

specifying means for specifying a location of the portable unit in the compartment based on changes in receptions of the response signal transmitted in response to the request signal of varying output level; and

notifying means for notifying the location of the portable unit specified by the specifying means.

2. The system according to claim 1, wherein:

the output varying means gradually increases the output level of the request signal in steps; and

the specifying means specifies the location of the portable unit based on a change from no reception to reception of the response signal.

3. The system according to claim 1, wherein:

the output varying means gradually decreases the output level of the request signal in steps; and

the specifying means specifies the location of the portable unit based on a change from reception to no reception of the response signal.

4. The system according to claim 1, wherein:

the transmitter means includes a plurality of transmitters provided to form a plurality of communication areas, which partly overlap.

5. The system according to claim 1, wherein:

the notifying means notifies the location by image or sound; and

the portable unit is caused to generate sound when the notifying means notifies the location of the portable unit.

6. A method for locating a portable unit in a compartment of a vehicle, the portable unit being carried by a vehicle user and capable of communication with an in-vehicle unit for controlling vehicle equipment, the method comprising:

transmitting, by the in-vehicle unit, a request signal in a vehicle compartment;

determining, by the in-vehicle unit, whether a response signal has been received from the portable unit in response the request signal;

specifying, by the in-vehicle unit, a location of the portable unit based on a change in determination result of the determining; and

notifying, by the in-vehicle unit, a specified location of the portable unit in the compartment, characterized by

varying, by the in-vehicle unit, an output level of the request signal gradually until the response signal is determined to have been received.

7. The method according to claim 6, wherein:

the transmitting transmits the request signal at at least first and second places in the compartment so that each request signal transmitted at the first and second places overlap between the first and second places.

8. The method according to claim 7, wherein:

the varying increases and decreases gradually the request signal transmitted at the first and the second places, respectively.

9. The method according to claim 7, wherein:

the transmitting transmits the request signal at two places, which are in a front half and a rear half in the compartment.

10. The method according to claim 6, wherein:

the transmitting is started only when a predetermined operation by the user is made.