Positioning device, mobile terminal, positioning method, and positioning program

• US 20050184905A1
• Filed: 01/21/2005
• Published: 08/25/2005
• Est. Priority Date: 01/23/2004
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kobayashi, Michio
• Granted Patent: US 7,068,217 B2
• Time in Patent Office: Days
• US Class Current: 342/357.310
• CPC Class Codes: G01S 19/252 Employing an initial estimate of location in generating assistance data

Abstract

A device and method are provided to reduce the time required for positioning by a GPS without allowing specific parties to occupy a communication channel. An initial location acquisition unit specifies a location of a broadcasting station based on a terrestrial digital broadcasting from the broadcasting station to set the location of the broadcasting station as an initial location for positioning in a positioning unit, and the positioning unit determines a present location by receiving a radio wave from a GPS satellite.

Claims

1. A positioning device comprising:

a positioning unit for positioning a present location by receiving a radio wave from a satellite;

a communication unit for acquiring at least one of;

information indicating an originating location of a public communication; and

information for specifying the originating location of the public communication based on the public communication; and

an initial location setting unit for setting an initial location to be used for the positioning based on the information acquired by the communication unit.

2. The positioning device according to claim 1, wherein the initial location setting unit comprises:

a first memory for storing the information acquired by the communication unit;

a second memory for storing a result of the positioning performed by the positioning unit;

a comparison unit for comparing information acquired by the communication unit in a previous positioning with information acquired by the communication unit in a current positioning; and

an estimation unit for estimating a distance between a current positioning location and a previous positioning location based on a result of the comparison,

the previous positioning location being used as an initial location to be used for the current positioning in the case where the distance between the current positioning location and the previous positioning location is in a predetermined range.

3. The positioning device according to claim 2, wherein the estimation unit uses at least one of:

IDs of receivable broadcasting stations;

number of the receivable broadcasting stations;

field intensities of received radio waves; and

received frequencies,

for the estimation of the distance between the current positioning location and the previous positioning location.

4. The positioning device according to any one of claims 1 to 3, wherein the public communication comprises at least one of:

analog radio broadcasting;

digital radio broadcasting;

analog TV broadcasting;

digital TV broadcasting; and

a road traffic information communication.

5. The positioning device according to claim 4, wherein the digital TV broadcasting comprises terrestrial digital broadcasting.

6. The positioning device according to claim 1, wherein the information for specifying the originating location of the public communication comprises at least one of a broadcasting frequency of a broadcasting station and ID information of the broadcasting station.

7. The positioning device according to claim 6, further comprising a correlation table wherein at least one of the broadcasting frequency of the broadcasting station and the ID information of the broadcasting station is correlated with at least one of location information of the broadcasting station and location information of a relay station of the broadcasting station.

8. The positioning device according to claim 7, wherein the initial location setting unit sets the initial location to be used for the positioning based on a result of reference to the correlation table.

9. A mobile terminal comprising:

a positioning unit for positioning a present location by receiving a radio wave from a satellite;

a communication unit for acquiring information indicating an originating location of at least one of

a public communication; and

information for specifying the originating location of the public communication based on the public communication;

an initial location setting unit for setting an initial location to be used for the positioning based on the information acquired by the communication unit; and

a display for displaying a result obtained by the positioning unit.

10. A positioning method comprising:

a step of acquiring information indicating at least one of an originating location of a public communication and information for specifying the originating location of the public communication based on the public communication;

a step of setting an initial location based on the information acquired by the communication unit; and

a step of positioning a present location by receiving a radio wave from a satellite with the use of the set initial location.

11. A positioning program comprising causing a computer to execute:

a step of acquiring information indicating at least one of an originating location of a public communication and information for specifying the originating location of the public communication based on the public communication;

a step of setting an initial location based on the information acquired by the communication unit; and

a step of positioning a present location by receiving a radio wave from a satellite with the use of the set initial location.