Mobile device for vehicle

• US 8,232,863 B2
• Filed: 01/15/2010
• Issued: 07/31/2012
• Est. Priority Date: 02/06/2009
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Nakajima, Satoshi, Hayasaka, Satoshi, Sato, Masaki, Takahashi, Jun
• Primary Examiner(s): Mehmood, Jennifer
• Assistant Examiner(s): SMALL, NAOMI J
• Application Number:
  US12/688,432
• Publication Number:
  US 20100201483A1
• Time in Patent Office: 928 Days
• Field of Search: 340/5.61
• US Class Current: 340/5.61
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/64 using a proximity sensor
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence

Abstract

A mobile device for a vehicle includes a receiving unit that receives transmission signals transmitted from individual transmitting antennas of a vehicle-side device; a control unit that determines distances to the individual transmitting antennas using the signal strengths of the received transmission signals; and a transmitting unit that transmits, to the vehicle-side device using wireless communication, data items indicating the distances. In a time period in which communication is not performed between the mobile device and the vehicle-side device, the signal strength of a received signal is measured, thereby obtaining a measurement value, and the measurement value is stored as a noise element in a memory. When communication between the mobile device and the vehicle-side device is performed, correction for noise is performed on the signal strengths of the transmission signals transmitted from the transmitting antennas, and the distances are determined.

Claims

1. A mobile device for a vehicle, the mobile device comprising:

a receiving unit configured to receive transmission signals, each of the transmission signals being transmitted from a corresponding one of a plurality of transmitting antennas of a vehicle-side device;

a control unit configured to determine a distance to each of the plurality of transmitting antennas using a signal strength of a corresponding one of the transmission signals received by the receiving unit; and

a transmitting unit configured to transmit, to the vehicle-side device, data items indicating the distances to the plurality of transmitting antennas determined by the control unit,

wherein, in a time period in which communication is not performed between the mobile device and the vehicle-side device, the control unit measures a signal strength of a signal received by the receiving unit to obtain a measurement value and stores the measurement value as a noise element, and, when communication is performed between the mobile device and the vehicle-side device, the control unit performs correction for noise on the signal strengths of the transmission signals, each of the transmission signals being transmitted from a corresponding one of the plurality of transmitting antennas, and determines the distances to the plurality of transmitting antennas,

wherein the control unit compares a distance Lsn calculated using the signal strength of each of the transmission signals including the noise element with a distance Ln calculated using only the noise element, and, when a ratio of the distance Ln to the distance Lsn is larger than a predetermined value, the control unit transmits, as the distance to a corresponding one of the plurality of transmitting antennas, an alternative data item with which malfunction in the vehicle-side device is prevented.

2. The mobile device for a vehicle according to claim 1, wherein the control unit transmits a data item indicating a maximum distance as the alternative data item with which malfunction in the vehicle-side device is prevented.