초록 ▼

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 determ

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.

대표청구항 ▼

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 positioni

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.