Determining location information using sampled data containing location-determining signals and noise

• US 6,535,163 B1
• Filed: 06/22/2001
• Issued: 03/18/2003
• Est. Priority Date: 06/22/2001
• Status: Expired due to Term

• Current Assignee: CSR Technology Holdings Inc. (Qualcomm, Inc.)
• Original Assignee: Enuvis Inc. (Qualcomm, Inc.)
• Inventors: Stone, Jesse Robert, Fong, Wungkum, Van Roy, Benjamin, Chou, Andrew, Mann, Wallace, Tsitsiklis, John, Sahai, Anant
• Primary Examiner(s): Phan, Dao
• Application Number:
  US09/888,337
• Time in Patent Office: 634 Days
• Field of Search: 342/357.01, 342/357.06, 342/357.12, 342/457, 701/213, 701/215, 455/456, 455/457
• US Class Current: 342/357.63
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence

Abstract

To determine the location of a signal receiver, sampled data received from a receiver is divided into data segments of increasing length. Current ranges for a delay value and for a modulation frequency value are calculated relative to each satellite signal source that is overhead the signal receiver. Using the data segments of increasing length, the current ranges, estimates for the delay value and for the modulation frequency value are then iteratively calculated and updated. For each signal source, I and Q correlation integrals and their magnitude values are calculated using the modulation frequency value estimate and each of a range of delay values centered around the delay value estimate. The resulting magnitude-curve is interpolated using the calculated magnitude values. The location of the receiver is calculated using the shape of the magnitude-curve to represent the I and Q correlation integrals for each signal source.

Claims

1. A method for determining a location of a receiver, the method comprising the computer-implemented steps of:

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that is overhead the receiver;

calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by using segments of increasing length of a sampled data that is associated with a received signal that is received at the receiver;

updating the current value range for the delay value and the current value range for the modulation frequency value based on the estimate for the delay value and the estimate for the modulation frequency value;

determining a current search range for the delay value and a current search range for the modulation frequency value;

corresponding to each signal source from the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for;

a set of delay values from within the current search range for the delay value, wherein the current search range for the delay value includes delay values that surround the estimate of the delay value; and

a set of modulation frequency values from within the current search range for the modulation frequency value, wherein the current search range for the modulation frequency value includes modulation frequency values that surround the estimate of the modulation frequency value;

corresponding to each signal source from the set of signal sources, determining interpolated calculations of I and Q correlation integrals by interpolating the calculations of I and Q correlation integrals based on the set of magnitude calculations and a magnitude value corresponding to the estimate of the delay value and the estimate of modulation frequency value; and

calculating the location of the receiver by using the interpolated calculations of I and Q correlation integrals for each signal source.

2. The method of claim 1, further comprising receiving from the receiver sampled data associated with the received signal.

3. The method of claim 1, wherein calculating a current value range for a delay value corresponding to each signal source is based on:

an approximate position information that is associated with the receiver relative to an approximate position information that is associated with each signal source; and

an approximate time information that the receiver received the received signal.

4. The method of claim 1, wherein calculating a current value range for a modulation frequency value corresponding to each signal source is based on:

a clock correction factor information of the signal source relative to a clock correction factor information of the receiver;

ephemeris information associated with the signal source;

navigation bit information associated with the signal source; and

a type of filter that is used for sampling the received signal to produce the sampled data.

5. The method of claim 1, wherein calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source involves using navigation bit information associated with each signal source.

6. The method of claim 1, wherein corresponding to each signal source from the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within the current search range for the delay value and for a set of modulation frequency values within the current search range for the modulation frequency value involves using navigation bit information associated with each signal source.

7. The method of claim 1, wherein corresponding to each signal source from the set of signal sources, interpolating the calculations of the I and Q correlation integrals involves using navigation bit information associated with each signal source.

8. The method of claim 1, wherein corresponding to each signal source from the set of signal sources, interpolating the calculations of I and Q correlation integrals is based on a type of filter that is used for sampling the received signal.

9. The method of claim 1, wherein the increasing lengths of the sampled data is obtained by dividing the sampled data into a set of segments of data, wherein each successive segment of data from the set of segments of data is formed by including all previous segments of data plus additional data from the sampled to reach a pre-determined segment length.

10. The method of claim 9, wherein a pre-determined segment length for a (j+1)^th successive segment of data is a number L times 2 to the power of j, wherein j ranges in value from zero to a total number of successive segments and wherein the number L is a positive integer.

11. The method of claim 1, wherein calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by using increasing lengths of the sampled data further comprises the steps of:

Step A;

dividing the sampled data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

Step B;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be a selected segment of data;

Step C;

selecting one signal source that has not been previously selected from a set of signal sources that is overhead the receiver to be a selected signal source;

Step D;

estimating the modulation frequency value based on the selected signal source and the selected segment of data by performing the steps of;

Step E;

computing the current value range for a delay value and the current value range for a modulation frequency value associated with the received signal if not previously computed based on the selected signal source;

Step F;

updating the current value range for the delay value and updating the current value range for the modulation frequency value based on the selected signal source and the selected segment of data if a set of criteria is satisfied, wherein the set of criteria comprises;

if the current value range for the delay value and current value range for the modulation frequency value are previously computed; and

if an estimate of the modulation frequency value satisfies a pre-determined tolerance value of modulation frequency value and an estimate of the delay value satisfies a pre-determined tolerance value of the delay value;

Step G;

repeating step C through step G until all the signal sources from the set of signal sources have been selected as the selected satellite;

Step H;

repeating steps B through H until all segments of data from the set of segments of data have been selected as the selected segment of data.

12. The method of claim 1, wherein the current search range for the delay values comprises discrete delay values, wherein a distance between one delay value from a next delay value equals a time between consecutive samples in the sampled data.

13. The method of claim 1, wherein the current search range for the modulation frequency value is based on a length of each segment that is being processed.

14. A method for determining a location of a receiver, the method comprising the computer-implemented steps of:

receiving from the receiver, sampled data associated with a received signal;

corresponding to each signal source from the set of signal sources that is overhead the receiver, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within a current value range for the delay value, wherein the set of delay values include an estimate of the delay value and delay values surrounding the estimate of the delay value;

determining interpolated calculations of I and Q correlation integrals by interpolating the I and Q correlation integrals based on the set of magnitude calculations; and

calculating the location of the receiver by using the interpolated calculations of I and Q correlation integrals for each signal source.

15. A method for determining a location of a receiver, the method comprising the computer-implemented steps of:

receiving from the receiver, sampled data associated with a received signal;

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that is overhead the receiver;

calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by performing the steps of;

Step A;

dividing the sampled data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

Step B;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be a selected segment of data;

Step C;

selecting one signal source that has not been previously selected from a set of signal sources that is overhead the receiver to be a selected signal source;

Step D;

updating the current value range for the delay value and updating the current value range for the modulation frequency value based on the selected signal source and the selected segment of data if a set of criteria is satisfied, wherein the set of criteria comprises;

if the current value range for the delay value and the current value range for the modulation frequency value are previously computed; and

an estimate of the modulation frequency value satisfies a pre-determined tolerance value of modulation frequency value and an estimate of the delay value satisfies a pre-determined tolerance value of the delay value;

Step E;

repeating step C through step E until all the signal sources from the set of signal sources have been selected as the selected satellite;

Step F;

repeating steps B through F until all segments of data from the set of segments of data have been selected as the selected segment of data;

corresponding to each signal source from the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within the current value range for the delay value, wherein the set of delay values includes delay values that surround the estimate of the delay value;

corresponding to each signal source from the set of signal sources, determining interpolated calculations of I and Q correlation integrals by interpolating the calculations of I and Q correlation integrals based on the set of magnitude calculations and the magnitude value corresponding to the estimate of the delay value; and

calculating the location of the receiver by using interpolated calculations of I and Q correlation integrals for each signal source.

16. A computer-readable medium carrying one or more sequences of instructions for determining a location of a receiver, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that is overhead the receiver;

calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by using segments of increasing length of a sampled data that is associated with a received signal that is received at the receiver;

updating the current value range for the delay value and the current value range for the modulation frequency value based on the estimate for the delay value and the estimate for the modulation frequency value;

determining a current search range for the delay value and a current search range for the modulation frequency value;

corresponding to each signal source from the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for;

a set of delay values from within the current search range for the delay value, wherein the current search range for the delay value includes delay values that surround the estimate of the delay value; and

a set of modulation frequency values from within the current search range for the modulation frequency value, wherein the current search range for the modulation frequency value includes modulation frequency values that surround the estimate of the modulation frequency value;

corresponding to each signal source from the set of signal sources, determining interpolated calculations of I and Q correlation integrals by interpolating the calculations of I and Q correlation integrals based on the set of magnitude calculations and a magnitude value corresponding to the estimate of the delay value and the estimate of modulation frequency value; and

calculating the location of the receiver by using the interpolated calculations of I and Q correlation integrals for each signal source.

17. The computer-readable medium of claim 16, further comprising receiving from the receiver sampled data associated with the received signal.

18. The computer-readable medium of claim 16, wherein calculating a current value range for a delay value corresponding to each signal source is based on:

an approximate position information that is associated with the receiver relative to an approximate position information that is associated with each signal source; and

an approximate time information that the receiver received the received signal.

19. The computer-readable medium of claim 16, wherein calculating a current value range for a modulation frequency value corresponding to each signal source is based on:

a clock correction factor information of the signal source relative to a clock correction factor information of the receiver;

ephemeris information associated with the signal source;

navigation bit information associated with the signal source; and

a type of filter that is used for sampling the received signal to produce the sampled data.

20. The computer-readable medium of claim 16, wherein calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source involves using navigation bit information associated with each signal source.

21. The computer-readable medium of claim 16, wherein corresponding to each signal source from the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within the current search range for the delay value and for a set of modulation frequency values within the current search range for the modulation frequency value involves using navigation bit information associated with each signal source.

22. The computer-readable medium of claim 16, wherein corresponding to each signal source from the set of signal sources, interpolating the calculations of the I and Q correlation integrals involves using navigation bit information associated with each signal source.

23. The computer-readable medium of claim 16, wherein corresponding to each signal source from the set of signal sources, interpolating the calculations of I and Q correlation integrals is based on a type of filter that is used for sampling the received signal.

24. The computer-readable medium of claim 16, wherein the increasing lengths of the sampled data is obtained by dividing the sampled data into a set of segments of data, wherein each successive segment of data from the set of segments of data is formed by including all previous segments of data plus additional data from the sampled to reach a pre-determined segment length.

25. The computer-readable medium of claim 24, wherein a pre-determined segment length for a (j+16)^th successive segment of data is a number L times 17 to the power of j, wherein j ranges in value from zero to a total number of successive segments and wherein the number L is a positive integer.

26. The computer-readable medium of claim 16, wherein calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by using increasing lengths of the sampled data further comprises the steps of:

Step A;

dividing the sampled data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

Step B;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be a selected segment of data;

Step C;

selecting one signal source that has not been previously selected from a set of signal sources that is overhead the receiver to be a selected signal source;

Step D;

estimating the modulation frequency value based on the selected signal source and the selected segment of data by performing the steps of;

Step E;

computing the current value range for a delay value and the current value range for a modulation frequency value associated with the received signal if not previously computed based on the selected signal source;

Step F;

updating the current value range for the delay value and updating the current value range for the modulation frequency value based on the selected signal source and the selected segment of data if a set of criteria is satisfied, wherein the set of criteria comprises;

if the current value range for the delay value and current value range for the modulation frequency value are previously computed; and

if an estimate of the modulation frequency value satisfies a pre-determined tolerance value of modulation frequency value and an estimate of the delay value satisfies a pre-determined tolerance value of the delay value;

Step G;

repeating step C through step G until all the signal sources from the set of signal sources have been selected as the selected satellite;

Step H;

repeating steps B through H until all segments of data from the set of segments of data have been selected as the selected segment of data.

27. The computer-readable medium of claim 16, wherein the current search range for the delay values comprises discrete delay values, wherein a distance between one delay value from a next delay value equals a time between consecutive samples in the sampled data.

28. The computer-readable medium of claim 16, wherein the current search range for the modulation frequency value is based on a length of each segment that is being processed.

29. A computer-readable medium carrying one or more sequences of instructions for determining a location of a receiver, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

receiving from the receiver, sampled data associated with a received signal;

corresponding to each signal source from the set of signal sources that is overhead the receiver, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within a current value range for the delay value, wherein the set of delay values include an estimate of the delay value and delay values surrounding the estimate of the delay value;

determining interpolated calculations of I and Q correlation integrals by interpolating the I and Q correlation integrals based on the set of magnitude calculations; and

calculating the location of the receiver by using the interpolated calculations of I and Q correlation integrals for each signal source.

30. A computer-readable medium carrying one or more sequences of instructions for determining a location of a receiver, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

receiving from the receiver, sampled data associated with a received signal;

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that is overhead the receiver;

calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by performing the steps of;

Step A;

dividing the sampled data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

Step B;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be a selected segment of data;

Step C;

selecting one signal source that has not been previously selected from a set of signal sources that is overhead the receiver to be a selected signal source;

Step D;

updating the current value range for the delay value and updating the current value range for the modulation frequency value based on the selected signal source and the selected segment of data if a set of criteria is satisfied, wherein the set of criteria comprises;

if the current value range for the delay value and the current value range for the modulation frequency value are previously computed; and

if an estimate of the modulation frequency value satisfies a pre-determined tolerance value of modulation frequency value and an estimate of the delay value satisfies a pre-determined tolerance value of the delay value;

Step E;

repeating step C through step E until all the signal sources from the set of signal sources have been selected as the selected satellite;

Step F;

repeating steps B through F until all segments of data from the set of segments of data have been selected as the selected segment of data;

corresponding to each signal source from- the set of signal sources, using the sampled data to calculate a set of magnitude calculations of I and Q correlation integrals for a set of delay values from within the current value range for the delay value, wherein the set of delay values includes delay values that surround the estimate of the delay value;

corresponding to each signal source from the set of signal sources, determining interpolated calculations of I and Q correlation integrals by interpolating the calculations of I and Q correlation integrals based on the set of magnitude calculations and the magnitude value corresponding to the estimate of the delay value; and

calculating the location of the receiver by using interpolated calculations of I and Q correlation integrals for each signal source.

31. A method for determining spatio-temporal parameters of a receiver, the method comprising the computer-implemented steps of:

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that are potentially visible by the receiver;

determining a current search range for the delay value corresponding to each signal source from the set of signal sources, wherein the current search range for the delay value is contained in the current value range for the delay value;

determining a current search range for the modulation frequency value corresponding to each signal source from the set of signal sources, wherein the current search range for the modulation frequency value is contained in the current value range for the modulation frequency value;

corresponding to each signal source from the set of signal sources, calculating a set of I and Q correlation integrals for a current segment, associated with the current search range for the delay value and the current search range for the modulation frequency value, by using segments of increasing length of data that is associated with a received signal that is received at the receiver, wherein calculating the set of I and Q correlation integrals for the current segment makes use of efficient methods for calculating correlation sums at multiple modulation frequency values;

updating the current value range for the delay value and the current value range for the modulation frequency value, corresponding to each signal source from the set of signal sources, based on a set of magnitude calculations associated with the set of I and Q correlation integrals for the current segment;

updating the current search range for the delay value and the current search range for the modulation frequency value, corresponding to each signal source from the set of signal sources, based on the current value range for the delay value and the current value range for the modulation frequency value corresponding to each signal source from the set of signal sources; and

determining the spatio-temporal parameters of the receiver by using interpolated calculations of I and Q correlation integrals for each acquired signal source.

32. The method of claim 31, further comprising receiving from the receiver data associated with the received signal.

33. The method of claim 31, wherein calculating the current value range for the delay value corresponding to each signal source is based on:

an approximate position information that is associated with the receiver relative to an approximate position information that is associated with each signal source;

an approximate time information that the receiver received the received signal;

a clock correction factor information of the signal source relative to a clock correction factor information of the receiver; and

ephemeris information associated with the signal source.

34. The method of claim 33, wherein calculating the current value range for the delay value involves a calculation based on a mathematical representation of a feasible region for the spatio-temporal parameters.

35. The method of claim 34 wherein the calculation based on the mathematical representation of the feasible region for the spatio-temporal parameters involves using mathematical programming techniques.

36. The method of claim 35 wherein using mathematical programming techniques, involves using linear programming techniques.

37. The method of claim 31, wherein calculating the current value range for the modulation frequency value corresponding to each signal source is based on:

an approximate position information that is associated with the receiver relative to an approximate position information that is associated with each signal source; and

an approximate time information that the receiver received the received signal; and

a clock correction factor information of the signal source relative to a clock correction factor information of the receiver; and

ephemeris information associated with the signal source; and

operational details of the receiver that is used for receiving the received signal.

38. The method of claim 37, wherein calculating the current value range for the modulation frequency value involves a calculation based on a mathematical representation of a feasible region for the spatio-temporal parameters.

39. The method of claim 38 wherein the calculation based on the mathematical representation of the feasible region for the spatio-temporal parameters involves using mathematical programming techniques.

40. The method of claim 39 wherein using mathematical programming techniques, involves using linear programming techniques.

41. The method of claim 31, wherein determining the current search range for the delay value corresponding to each signal source from the set of signal sources involves determining a grid of delay values within the current value range for the delay value corresponding to the signal source.

42. The method of claim 31, wherein determining the current search range for the modulation frequency value corresponding to each signal source from the set of signal sources involves determining a grid of modulation frequency values within the current value range for the modulation frequency value corresponding to the signal source.

43. The method of claim 31 wherein each signal source from the set of signal sources that is potentially visible by the receiver is a GPS satellite.

44. The method of claim 43, wherein corresponding to each signal source from the set of signal sources, calculating the set of I and Q correlation integrals for the current segment involves using navigation bit information associated with each signal source.

45. The method of claim 31, wherein updating the current value range for the delay value, and the current value range for the modulation frequency value, corresponding to each signal source from the set of signal sources, involves a calculation based on a mathematical representation of a feasible region for the spatio-temporal parameters.

46. The method of claim 45 wherein the calculation based on the mathematical representation of the feasible region for the spatio-temporal parameters involves using mathematical programming techniques.

47. The method of claim 46 wherein using mathematical programming techniques, involves using linear programming techniques.

48. The method of claim 31, wherein the segments of increasing length of data is obtained by dividing the data into a set of segments of data, wherein each successive segment of data from the set of segments of data is formed by including all previous segments of data plus additional data from the data to reach a pre-determined segment length.

49. The method of claim 48, wherein the pre-determined segment length for a (j+1)^th successive segment of data is a number L times 2 to the power of j, wherein j ranges in value from zero to a total number of successive segments and wherein the number L is a positive integer.

50. The method of claim 31, wherein calculating the set of I and Q correlation integrals for the current segment, associated with the current search range for the delay value and the current search range for the modulation frequency value, comprises the steps of:

Step A;

dividing the data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

Step B;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be the current segment of data;

Step C;

selecting one signal source that has not been previously selected for the current segment of data from the set of signal sources that are potentially visible by the receiver to be a selected signal source;

Step D;

calculating the set of I and Q correlation integrals for the current segment of data for every combination of a delay value from within the current search range for the delay value for the selected signal source and a modulation frequency value within the current search range for the modulation frequency value for the selected signal source;

Step E;

repeating steps C through step D until all the signal sources from the set of signal sources have been selected as the selected signal source; and

Step F;

repeating steps B through E until all segments of data from the set of segments of data have been selected as the current segment of data.

51. The method of claim 50, wherein updating the current value range for the delay value and the current value range for the modulation frequency value, corresponding to each signal source from the set of signal sources, comprises the steps of:

Step A;

using the set of magnitude calculations associated with the set of I and Q correlation integrals for the current segment of data to determine whether each signal source has been acquired, by comparing the set of magnitude calculations to a threshold;

Step B;

updating the current value range for the delay value and the current value range for the modulation frequency value corresponding to each signal source from the set of signal sources that has been acquired, to be intervals surrounding the delay value and modulation frequency value for which the magnitude calculations associated with the set of I and Q correlation integrals are largest; and

Step C;

updating the current value range for the delay value and the current value range for the modulation frequency value corresponding to each signal source that has not been acquired, by keeping only those values that are compatible with the current value range for the delay value and the current value range for the modulation frequency value associated with the signal sources that have been acquired.

52. The method of claim 31, wherein the data that is associated with a received signal that is received at the receiver are sampled data.

53. The method of claim 52, wherein the current search range for the delay value comprises discrete delay values, wherein a distance from one delay value to a next delay value equals a time between consecutive samples in the sampled data.

54. The method of claim 31, wherein the current search range for the modulation frequency value is based on a length of the current segment that is being processed.

55. The method of claim 31, wherein determining the spatio-temporal parameters of the receiver involves using the interpolated calculations of I and Q correlation integrals for each acquired signal source to determine an estimate of the delay value corresponding to each acquired signal source and then using the estimate of the delay value in a weighted least squares triangulation algorithm.

56. The method of claim 50 wherein calculating I and Q correlation integrals comprises calculating correlation sums that correlate the received signal with a known GPS signal.

57. The method of claim 51 wherein calculating I and Q correlation integrals comprises calculating correlation sums that correlate the received signal with a known GPS signal.

58. The method of claim 55 wherein calculating I and Q correlation integrals comprises calculating correlation sums that correlate the received signal with a known GPS signal.

59. The method of claim 31, wherein the spatio-temporal parameters of the receiver include a position of the receiver and a time at which the received signal is received at the receiver.

60. The method of claim 31, wherein the spatio-temporal parameters of the receiver include a velocity of the receiver.

61. The method of claim 31, wherein the spatio-temporal parameters of the receiver include a clock drift at the receiver.

62. The method of claim 31, wherein the spatio-temporal parameters of the receiver include a position of the receiver, a time at which the received signal is received at the receiver, a velocity of the receiver, and a clock drift at the receiver.

63. A method for determining spatio-temporal parameters of a receiver, the method comprising the computer-implemented steps of:

receiving from the receiver sampled data associated with a received signal;

receiving from the receiver and from other sources information related to a set of potential signal sources and to the receiver spatio-temporal parameters and characteristics;

calculating a current value range for a delay value and a current value range for a modulation frequency value corresponding to each signal source from a set of signal sources that are potentially visible by the receiver;

dividing the sampled data into a set of segments of data, wherein each successive segment of data in the set of segments of data is formed by elongating a previous segment of data;

calculating an estimate for the delay value and an estimate for the modulation frequency value corresponding to each signal source by performing the steps of;

Step A;

selecting a shortest segment of data that has not been previously selected from the set of segments of data to be a current segment of data;

Step B;

selecting one signal source that has not been previously selected for the current segment of data from the set of signal sources that are potentially visible by the receiver to be a selected signal source;

Step C;

determining a current search range for the delay value from within the current value range for the delay value corresponding to the selected signal source;

Step D;

determining a current search range for the modulation frequency value from within the current value range for the modulation frequency value corresponding to the selected signal source;

Step E;

using the sampled data in the current segment of data to calculate I and correlation integrals corresponding to the selected signal source, for the delay values in the current search range for the delay value and for the modulation frequency values in the current search range for the modulation frequency values, using efficient methods for calculating correlation sums at multiple modulation frequency values;

Step F;

calculating a set of magnitude calculations of the I and Q correlation integrals;

Step G;

determining that the selected signal source has been acquired if it has been acquired during a previous step, or if the set of magnitude calculations of the I and Q correlation integrals contains a magnitude calculation that exceeds a threshold;

Step H;

updating the current value range for the delay value and updating the current value range for the modulation frequency value, corresponding to the selected signal source, based on whether the source has been determined to be acquired and based on interpolated calculations of the I and Q correlation integrals;

Step I;

repeating step B through step H until all the signal sources from the set of signal sources have been selected as the selected signal source;

Step J;

updating the current value range for the delay value and updating the current value range for the modulation frequency value corresponding to the each signal source, using a linear programming method;

Step K;

repeating steps A through I until all segments of data from the set of segments of data have been selected as the current segment of data;

corresponding to each signal source from the set of signal sources that has been determined to be acquired, using the current value range and the available I and Q correlation integrals to determine an estimate of the delay value; and

determining the spatio-temporal parameters of the receiver by using the estimate of the delay value corresponding to each signal source that has been determined to be acquired, in a weighted least squares triangulation method.

64. The method of claim 63 wherein the received signal is a GPS signal.

65. The method of claim 63, wherein the spatio-temporal parameters of the receiver include a position of the receiver and a time at which the received signal is received at the receiver.

66. The method of claim 63, wherein the spatio-temporal parameters of the receiver include a velocity of the receiver and a time at which the received signal is received at the receiver.

67. The method of claim 63, wherein the spatio-temporal parameters of the receiver include a clock drift at the receiver.

68. The method of claim 63, wherein the spatio-temporal parameters of the receiver include a position of the receiver, a time at which the received signal is received at the receiver, a velocity of the receiver, and a clock drift at the receiver.