Psuedo television transmitters for position location

1. An apparatus comprising:

a signal generator to generate an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

a wireless transmitter to wirelessly transmit the RF signal; and

a self-check unit comprising

a receiver to receive the RF signal, and to recover the ranging signal from the RF signal,

a pseudorange circuit to determine a pseudorange based on the ranging signal, and

a self-test circuit to generate a self-test output based on the pseudorange;

wherein the self-test circuit comprises

a wireless receiver to wirelessly receive a second RF signal comprising a second ranging signal comprising a component of a television signal, and to recover the second ranging signal from the second RF signal, and

a second pseudorange circuit to determine a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal,

wherein a range between the station and the apparatus is determined based on the pseudoranges.

2. The apparatus of claim 1 , further comprising:

a wireless receiver to wirelessly receive a plurality of second RF signals; and

a signal processor to determine a position of the wireless transmitter based on the second RF signals;

wherein the RF signal comprises a signal representing the position of the wireless transmitter.

3. The apparatus of claim 2 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

4. The apparatus of claim 1 :

wherein the signal generator generates a second RF signal comprising the ranging signal;

wherein the wireless transmitter wirelessly transmits the second RF signal;

wherein the receiver receives the second RF signal, and recovers the ranging signal from the second RF signal;

wherein the pseudorange circuit determines a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein the self-test circuit comprises

a group delay circuit to determine a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

5. The apparatus of claim 1 , wherein the self-test circuit comprises:

a correlator to generate a correlation output based on the ranging signal and a reference waveform; and

a comparator to generate a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.

6. The apparatus of claim 1 , wherein the self-test circuit further comprises:

a range circuit to determine the range, wherein the self-test output represents the range.

7. An apparatus comprising:

a signal generator to generate an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

a wireless transmitter to wirelessly transmit the RF signal;

a self-check unit comprising

a receiver to receive the RF signal, and to recover the ranging signal from the RF signal,

a pseudorange circuit to determine a pseudorange based on the ranging signal, and

a self-test circuit to generate a self-test output based on the pseudorange; and

a first clock, wherein the ranging signals are generated according to the first clock;

wherein the self-test circuit comprises

a wireless receiver to wirelessly receive a second RF signal comprising a second ranging signal comprising a component of a television signal, wherein the second ranging signal is generated according to a second clock, and to recover the second ranging signal from the second RF signal, and

a second pseudorange circuit to determine a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal, and

wherein a clock bias between the first and second clocks is determined based on the pseudoranges.

8. The apparatus of claim 7 , wherein the self-test circuit further comprises:

a clock bias circuit to determine the clock bias, wherein the self-test output represents the clock bias.

9. The apparatus of claim 7 , further comprising:

a wireless receiver to wirelessly receive a plurality of second RF signals; and

a signal processor to determine a position of the wireless transmitter based on the second RF signals;

wherein the RF signal comprises a signal representing the position of the wireless transmitter.

10. The apparatus of claim 9 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

11. The apparatus of claim 7 :

wherein the signal generator generates a second RF signal comprising the ranging signal;

wherein the wireless transmitter wirelessly transmits the second RF signal;

wherein the receiver receives the second RF signal, and recovers the ranging signal from the second RF signal;

wherein the pseudorange circuit determines a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein the self-test circuit comprises

a group delay circuit to determine a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

12. The apparatus of claim 7 , wherein the self-test circuit comprises:

a correlator to generate a correlation output based on the ranging signal and a reference waveform; and

a comparator to generate a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.

13. An apparatus comprising:

means for generating an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

means for wirelessly transmitting the RF signal; and

means for self-checking comprising

means for receiving the RF signal, and for recovering the ranging signal from the RF signal,

means for determining a pseudorange based on the ranging signal, and

means for generating a self-test output based on the pseudorange;

wherein the means for generating a self-test output comprises

means for wirelessly receiving a second RF signal comprising a second ranging signal comprising a component of a television signal, and for recovering the second ranging signal from the second RF signal, and

means for determining a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal,

wherein a range between the station and the apparatus is determined based on the pseudoranges.

14. The apparatus of claim 13 , further comprising:

means for wirelessly receiving a plurality of second RF signals; and

means for determining a position of the means for wirelessly transmitting based on the second RF signals;

wherein the RF signal comprises a signal representing the position of the means for wirelessly transmitting.

15. The apparatus of claim 14 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

16. The apparatus of claim 13 :

wherein the means for generating generates a second RF signal comprising the ranging signal;

wherein the means for wirelessly transmitting wirelessly transmits the second RF signal;

wherein the means for receiving receives the second RF signal, and recovers the ranging signal from the second RF signal;

wherein the means for determining a pseudorange determines a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein the means for generating a self-test output comprises

means for determining a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

17. The apparatus of claim 13 , wherein the means for generating a self-test output comprises:

means for generating a correlation output based on the ranging signal and a reference waveform; and

means for generating a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.

18. The apparatus of claim 13 , wherein the means for generating a self-test output further comprises:

means for determining the range, wherein the self-test output represents the range.

19. An apparatus comprising:

means for generating an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

means for wirelessly transmitting the RF signal;

means for self-checking comprising

means for receiving the RF signal, and for recovering the ranging signal from the RF signal,

means for determining a pseudorange based on the ranging signal, and

means for generating a self-test output based on the pseudorange; and

first means for clocking, wherein the ranging signals are generated according to the first means for clocking;

wherein the means for generating a self-test output comprises

means for wirelessly receiving a second RF signal comprising a second ranging signal comprising a component of a television signal, wherein the second ranging signal is generated according to a second clock, and to recover the second ranging signal from the second RF signal, and

means for determining a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal, and

wherein a clock bias between the first means for clocking and the second clock is determined based on the pseudoranges.

20. The apparatus of claim 19 , wherein the means for generating a self-test output further comprises:

means for determining the clock bias, wherein the self-test output represents the clock bias.

21. The apparatus of claim 19 , further comprising:

means for wirelessly receiving a plurality of second RF signals; and

means for determining a position of the means for wirelessly transmitting based on the second RF signals;

wherein the RF signal comprises a signal representing the position of the means for wirelessly transmitting.

22. The apparatus of claim 21 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

23. The apparatus of claim 19 :

wherein the means for generating generates a second RF signal comprising the ranging signal;

wherein the means for wirelessly transmitting wirelessly transmits the second RF signal;

wherein the means for receiving receives the second RF signal, and recovers the ranging signal from the second RF signal;

wherein the means for determining a pseudorange determines a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein the means for generating a self-test output comprises

means for determining a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

24. The apparatus of claim 19 , wherein the means for generating a self-test output comprises:

means for generating a correlation output based on the ranging signal and a reference waveform; and

means for generating a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.

25. A method comprising:

generating an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

wirelessly transmitting the RF signal; and

self-checking comprising

receiving the RF signal,

recovering the ranging signal from the RF signal,

determining a pseudorange based on the ranging signal, and

generating a self-test output based on the pseudorange;

wherein generating a self-test output comprises

wirelessly receiving a second RF signal comprising a second ranging signal comprising a component of a television signal,

recovering the second ranging signal from the second RF signal, and

determining a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal,

wherein a range from the station is determined based on the pseudoranges.

26. The method of claim 25 , further comprising:

wirelessly receiving a plurality of second RF signals; and

determining a position based on the second RF signals;

wherein the RF signal comprises a signal representing the position.

27. The method of claim 26 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

28. The method of claim 25 , further comprising:

generating a second RF signal comprising the ranging signal;

wirelessly transmitting the second RF signal;

receiving the second RF signal;

recovering the ranging signal from the second RF signal;

determining a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein generating a self-test output comprises

determining a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

29. The method of claim 25 , wherein generating a self-test output comprises:

generating a correlation output based on the ranging signal and a reference waveform; and

generating a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.

30. The method of claim 25 , wherein generating a self-test output further comprises:

determining the range, wherein the self-test output represents the range.

31. A method comprising:

generating an radio-frequency (RF) signal comprising a ranging signal comprising a component of a television signal;

wirelessly transmitting the RF signal;

self-checking comprising

receiving the RF signal,

recovering the ranging signal from the RF signal,

determining a pseudorange based on the ranging signal, and

generating a self-test output based on the pseudorange; and

generating the ranging signals according to a first clock;

wherein generating a self-test output comprises

wirelessly receiving a second RF signal comprising a second ranging signal comprising a component of a television signal, wherein the second ranging signal is generated according to a second clock,

recovering the second ranging signal from the second RF signal, and

determining a second pseudorange based on the second ranging signal,

wherein a station comprising a transmitter of the second RF signal generates a third pseudorange based on the ranging signal and a fourth pseudorange based on the second ranging signal, and

wherein a clock bias between the first and second clocks is determined based on the pseudoranges.

32. The method of claim 31 , wherein generating the self-test output further comprises:

determining the clock bias, wherein the self-test output represents the clock bias.

33. The method of claim 31 , further comprising:

wirelessly receiving a plurality of second RF signals; and

determining a position based on the second RF signals;

wherein the RF signal comprises a signal representing the position.

34. The method of claim 33 , wherein the second RF signals comprise at least one of the group consisting of:

a television signal; and

a satellite positioning signal.

35. The method of claim 31 , further comprising:

generating a second RF signal comprising the ranging signal;

wirelessly transmitting the second RF signal;

receiving the second RF signal;

recovering the ranging signal from the second RF signal;

determining a second pseudorange based on the ranging signal recovered from the second RF signal; and

wherein generating a self-test output comprises

determining a relative group delay between the RF signals based on the pseudoranges; and

wherein the self-test output represents the relative group delay.

36. The method of claim 31 , wherein generating a self-test output comprises:

generating a correlation output based on the ranging signal and a reference waveform; and

generating a comparator output based on the correlation output and a correlation template; and

wherein the self-test output represents the comparator output.