Position location using global positioning signals augmented by broadcast television signals

1. An apparatus for determining the position of a user terminal, comprising:

a first receiver adapted to receive, at the user terminal, a broadcast digital television signal from a television signal transmitter; and

a second receiver adapted to receive, at the user terminal, a satellite positioning signal from a positioning satellite;

wherein a position of the user terminal is determined based on the broadcast digital television signal, the satellite positioning signal, a location of the television signal transmitter, and a location of the positioning satellite.

2. The apparatus of claim 1 , further comprising:

a processor adapted to determine the position of the user terminal based on the broadcast digital television signal, the satellite positioning signal, the location of the television signal transmitter, and the location of the positioning satellite.

3. The apparatus of claim 2 :

wherein the processor determines the position of the user terminal based on

a difference between a transmitter clock at the television signal transmitter and a known time reference, and

a relative radial velocity between the positioning satellite and the user terminal.

4. The apparatus of claim 3 :

wherein the processor determines a first pseudo-range between the user terminal and the television signal transmitter based on the broadcast digital television signal; and

wherein the processor determines a second pseudo-range between the user terminal and the positioning satellite based on the satellite positioning signal;

wherein the processor determines the position of the user terminal based on the first and second pseudo-ranges.

5. The apparatus of claim 1 , wherein the broadcast digital television signal is selected from the group consisting of:

an American Television Standards Committee (ATSC) digital television signal;

a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting-Terrestrial (DVB-T) signal; and

a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal.

6. An apparatus for determining the position of a user terminal, comprising:

first receiver means for receiving, at the user terminal, a broadcast digital television signal from a television signal transmitter; and

second receiver means for receiving, at the user terminal, a satellite positioning signal from a positioning satellite;

wherein a position of the user terminal is determined based on the broadcast digital television signal, the satellite positioning signal, a location of the television signal transmitter, and a location of the positioning satellite.

7. The apparatus of claim 6 , further comprising:

processor means for determining the position of the user terminal based on the broadcast digital television signal, the satellite positioning signal, the location of the television signal transmitter, and the location of the positioning satellite.

8. The apparatus of claim 7 :

wherein the processor means determines the position of the user terminal based on

a difference between a transmitter clock at the television signal transmitter and a known time reference, and

a relative radial velocity between the positioning satellite and the user terminal.

9. The apparatus of claim 8 :

wherein the processor means determines a first pseudo-range between the user terminal and the television signal transmitter based on the broadcast digital television signal; and

wherein the processor means determines a second pseudo-range between the user terminal and the positioning satellite based on the satellite positioning signal;

wherein the position of the user terminal is determined based on the first and second pseudo-ranges.

10. The apparatus of claim 6 , wherein the broadcast digital television signal is selected from the group consisting of:

an American Television Standards Committee (ATSC) digital television signal;

a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting-Terrestrial (DVB-T) signal; and

a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal.

11. A method for determining the position of a user terminal, comprising:

receiving, at the user terminal, a broadcast digital television signal from a television signal transmitter; and

receiving, at the user terminal, a satellite positioning signal from a positioning satellite;

wherein a position of the user terminal is determined based on the broadcast digital television signal, the satellite positioning signal, a location of the television signal transmitter, and a location of the positioning satellite.

12. The method of claim 11 , further comprising:

determining the position of the user terminal based on the broadcast digital television signal, the satellite positioning signal, the location of the television signal transmitter, and the location of the positioning satellite.

13. The method of claim 12 , wherein determining the position of the user terminal comprises:

determining the position of the user terminal based on

a difference between a transmitter clock at the television signal transmitter and a known time reference, and

a relative radial velocity between the positioning satellite and the user terminal.

14. The method of claim 13 , wherein determining the position of the user terminal further comprises:

determining a first pseudo-range between the user terminal and the television signal transmitter based on the broadcast digital television signal; and

determining a second pseudo-range between the user terminal and the positioning satellite based on the satellite positioning signal;

wherein the position of the user terminal is determined based on the first and second pseudo-ranges.

15. The method of claim 11 , wherein the broadcast digital television signal is selected from the group consisting of:

an American Television Standards Committee (ATSC) digital television signal;

a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting-Terrestrial (DVB-T) signal; and

a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal.

16. Computer-readable media embodying instructions executable by a computer to perform a method comprising:

determining the position of a user terminal based on

a broadcast digital television signal received at the user terminal from a television signal transmitter,

a satellite positioning signal received at the user terminal from a positioning satellite,

the location of the television signal transmitter, and

the location of the positioning satellite.

17. The computer-readable media of claim 16 , wherein determining the position of the user terminal comprises:

determining the position of the user terminal based on

a difference between a transmitter clock at the television signal transmitter and a known time reference, and

a relative radial velocity between the positioning satellite and the user terminal.

18. The computer-readable media of claim 17 , wherein determining the position of the user terminal further comprises:

determining a first pseudo-range between the user terminal and the television signal transmitter based on the broadcast digital television signal; and

determining a second pseudo-range between the user terminal and the positioning satellite based on the satellite positioning signal;

wherein the position of the user terminal is determined based on the first and second pseudo-ranges.

19. The computer-readable media of claim 16 , wherein the broadcast digital television signal is selected from the group consisting of:

an American Television Standards Committee (ATSC) digital television signal;

a European Telecommunications Standards Institute (ETSI) Digital Video Broadcasting-Terrestrial (DVB-T) signal; and

a Japanese Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) signal.