Position determination

• US 20020105460A1
• Filed: 10/18/2001
• Published: 08/08/2002
• Est. Priority Date: 11/01/2000
• Status: Active Grant

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Sladen, Peter
• Granted Patent: US 6,545,638 B2
• Time in Patent Office: Days
• US Class Current: 342/357.14
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

Dead reckoning is used to solve a location problem when a user is out of range of GPS coverage. A starting position is determined by tracking movements from a first position where GPS coverage is not available to a second position where GPS coverage is available. The starting position is then determined by backtracking from this known position.

Claims

1. A method of providing positional information to a receiver which is arranged to receive a positioning system signal, the signal providing information relating to the receiver'"'"'s current position, comprising the steps of:

tracking the receiver'"'"'s route from a first position at which the positioning system signal is not available to a second position at which the positioning system signal is available;

determining positional information defining the first position from the positioning system signal at the second position and the receiver'"'"'s route between the first and second positions; and

storing the positional information at the receiver.

2. A method according to claim 1, including determining the positional information defining the first position by back-tracking from the second position along the route taken by the receiver between the first and second positions.

3. A method according to claim 1, including using dead reckoning to track the receiver'"'"'s route between the first and second positions.

4. A method according to claim 1, comprising recalling the stored positional information from the receiver to define the first position relative to a known third position.

5. A method according to claim 1, wherein the positioning system comprises the Global Positioning System (GPS).

6. A device for providing positional information to a user, the device being arranged to receive a positioning system signal, the signal providing information relating to the current position of the device, comprising:

means for tracking the route of the device from a first position at which the positioning system signal is not available to a second position at which the positioning system signal is available;

means for determining positional information defining the first position from the positioning system signal at the second position and the receiver'"'"'s route between the first and second positions; and

means for storing the positional information.

7. A device according to claim 6, wherein the determining means comprise means for back-tracking from the second position along the route taken by the device between the first and second positions.

8. A device according to claim 6, wherein the tracking means comprises a dead reckoning system.

9. A device according to claim 6, wherein the device uses the stored positional information to define the first position relative to a known third position.

10. A device according to claim 6, comprising a Global Positioning System (GPS) receiver.

11. A device for providing positional information to a user, the device being arranged to receive a positioning system signal, the signal providing information relating to the current position of the device, comprising:

trading apparatus for tracking the route of the device from a first position at which the positioning system signal is not available to a second position at which the positioning system signal is available;

a positioning device for determining positional information defining the first position from the positioning system signal at the second position and the receiver'"'"'s route between the first and second positions; and

a storage element for storing the positional information.