Position determining device and method, and keyless entry system

Patent metadata

Field	Value
Publication number	US-2018106882-A1
Application number	US-201715705528-A
Country	US
Kind code	A1
Filing date	Sep 15, 2017
Priority date	Oct 19, 2016
Publication date	Apr 19, 2018
Grant date	—

Abstract

A position determining device is configured to determine the position of a portable device configured to receive one or more radio signals transmitted from one or more antennas inside a vehicle, respectively. The position determining device includes a processor configured to determine the open or closed state of a door of the vehicle for getting in and out of the vehicle, calculate an evaluation value related to the position of the portable device based on the received signal strength of the one or more radio signals at the portable device, and determine that the portable device is positioned inside the vehicle when the evaluation value satisfies a predetermined condition. The processor is configured to change at least one of the predetermined condition and a method of calculating the evaluation value in accordance with the determined open or closed state of the door.

First claim

What is claimed is:

1 . A position determining device configured to determine a position of a portable device configured to receive one or more radio signals transmitted from one or more antennas inside a vehicle, respectively, the position determining device comprising:
a memory; and a processor coupled to the memory, and configured to determine an open or closed state of a door of the vehicle for getting in and out of the vehicle; calculate an evaluation value related to the position of the portable device based on a received signal strength of the one or more radio signals at the portable device; and determine that the portable device is positioned inside the vehicle when the evaluation value satisfies a predetermined condition, wherein the processor is configured to change at least one of the predetermined condition and a method of calculating the evaluation value in accordance with the determined open or closed state of the door.

2 . The position determining device as claimed in claim 1 , wherein the processor is further configured to
calculate one or more distances between the one or more antennas and the portable device as the evaluation value based on the received signal strength of the one or more radio signals transmitted from the one or more antennas; determine that the portable device is positioned inside the vehicle when the one or more distances satisfy a predetermined first condition, in a case of determining that the door is closed as a result of determining the open or closed state of the door; and determine that the portable device is positioned inside the vehicle when the one or more distances satisfy a predetermined second condition different from the predetermined first condition, in a case of determining that the door is open as a result of determining the open or closed state of the door.

3 . The position determining device as claimed in claim 2 , wherein the processor is further configured to
determine the open or closed state of each of a plurality of doors of the vehicle, the plurality of doors including the door; and determine that the portable device is positioned inside the vehicle when the one or more distances satisfy the predetermined second condition, in a case of determining that at least the door among the plurality of doors is open as a result of determining the open or closed state of each of the plurality of doors, the predetermined second condition being set with respect to each of different combinations of the open or closed states of the plurality of doors.

4 . The position determining device as claimed in claim 2 , wherein
the predetermined first condition includes a condition that d≤TH 1 or a condition that d<TH 1 , where d is a distance from one of the one or more antennas to the portable device and TH 1 is a first threshold, and the predetermined second condition includes a condition that d≤TH 2 or a condition that d<TH 2 , where d is the distance from the one of the one or more antennas to the portable device and TH 2 is a second threshold, the second threshold being smaller than the first threshold.

5 . The position determining device as claimed in claim 2 , wherein
the predetermined first condition includes a condition that d≤TH 3 or a condition that d<TH 3 , where d is a sum of distances from two of the one or more antennas to the portable device and TH 3 is a third threshold, and the predetermined second condition includes a condition that d≤TH 4 or a condition that d<TH 4 , where d is the sum of the distances from the two of the one or more antennas to the portable device and TH 4 is a fourth threshold, the fourth threshold being smaller than the third threshold.

6 . The position determining device as claimed in claim 1 , wherein
the processor is further configured to
calculate a first Mahalanobis distance and a second Mahalanobis distance as the evaluation value when determining that the door is closed as a result of determining the open or closed state of the door; and
calculate a third Mahalanobis distance and a fourth Mahalanobis distance as the evaluation value when determining that the door is open as a result of determining the open or closed state of the door,
the first Mahalanobis distance is a Mahalanobis distance between a first data group and the received signal strength of the one or more radio signals received at the portable device, the first data group indicating a received signal strength of one or more radio signals from the one or more antennas received at a plurality of points inside the vehicle with the door being closed, the second Mahalanobis distance is a Mahalanobis distance between a second data group and the received signal strength of the one or more radio signals received at the portable device, the second data group indicating a received signal strength of one or more radio signals from the one or more antennas received at a plurality of points outside the vehicle with the door being closed, the third Mahalanobis distance is a Mahalanobis distance between a third data group and the received signal strength of the one or more radio signals received at the portable device, the third data group indicating a received signal strength of one or more radio signals from the one or more antennas received at a plurality of points inside the vehicle with the door being open, the fourth Mahalanobis distance is a Mahalanobis distance between a fourth data group and the received signal strength of the one or more radio signals received at the portable device, the fourth data group indicating a received signal strength of one or more radio signals from the one or more antennas received at a plurality of points outside the vehicle with the door being open, and the processor is further configured to
determine that the portable device is positioned inside the vehicle when the first Mahalanobis distance is shorter than the second Mahalanobis distance, in a case of determining that the door is closed as a result of determining the open or closed state of the door; and
determine that the portable device is positioned inside the vehicle when the third Mahalanobis distance is shorter than the fourth Mahalanobis distance, in a case of determining that the door is open as a result of determining the open or closed state of the door.

7 . The position determining device as claimed in claim 1 , wherein
the door is a slidable door, and the processor is configured to determine the open or closed state of the slidable door.

8 . A position determining method for determining a position of a portable device configured to receive one or more radio signals transmitted from one or more antennas inside a vehicle, respectively, the position determining method comprising:
determining, by a processor, an open or closed state of a door of the vehicle for getting in and out of the vehicle; calculating, by the processor, an evaluation value related to the position of the portable device based on a received signal strength of the one or more radio signals at the portable device; and determining, by the processor, that the portable device is positioned inside the vehicle when the evaluation value satisfies a predetermined condition, wherein at least one of the predetermined condition and a method of calculating the evaluation value is changed by the processor in accordance with the open or closed state of the door determined by said determining the open or closed state of the door.

9 . The position determining method as claimed in claim 8 , wherein
said calculating the evaluation value includes calculating one or more distances between the one or more antennas and the portable device as the evaluation value based on the received signal str

Assignees

• Alps Electric Co Ltd

Inventors

• Kanaga Mikihiko

Classifications

• G07C9/28

  the pass enabling tracking or indicating presence · CPC title

• B60R25/245 Primary

  where the antenna reception area plays a role · CPC title

• G01S11/06

  using intensity measurements · CPC title

• G01S5/0284 Primary

  Relative positioning · CPC title

• G07C2209/63

  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 title