Title:
Range finding system
Document Type and Number:
Japanese Patent JP6081895
Kind Code:
B2
Abstract:
Provided is a distance measurement system in which power consumption is minimized in an effective manner, the distance measurement system being suitable for applications such as a smart entry system in which a plurality of terminals are present. Distance measurement signal transmission/reception units (4a, 4b) transmit and receive, in a continuous manner, a radio signal for measuring the distance therebetween. A distance calculator (51) calculates the distance between the distance measurement signal transmission/reception units (4a, 4b) on the basis of the times at which the transmitted/received radio signal is transmitted/received. A representative setting unit (52) sets, as a representative, a portable terminal (1b) identified as having first entered a predetermined range by performing threshold value determination on the distance. In the terminal set as a representative, the process performed by the distance measurement signal transmission/reception unit (4b) is continued, and in a terminal that has not been set as a representative, the process performed by the distance measurement signal transmission/reception unit (4b) is stopped.
Inventors:
Shigeki Oyama
Yasutaka Nishimura
Takahito Yoshihara
Yasutaka Nishimura
Takahito Yoshihara
Application Number:
JP2013203897A
Publication Date:
February 15, 2017
Filing Date:
September 30, 2013
Export Citation:
Assignee:
KDDI CORPORATION
International Classes:
E05B49/00; H04M1/00
Domestic Patent References:
| JP5288473B2 | ||||
| JP2007278731A | ||||
| JP2012255311A |
Attorney, Agent or Firm:
Kiyotaka Sakamoto
Sanji Tanabe
Sanji Tanabe