SATELLITE POSITIONING WITH ASSISTED CALCULATION

• US 20120306690A1
• Filed: 06/14/2011
• Published: 12/06/2012
• Est. Priority Date: 06/01/2011
• Status: Abandoned Application

• Current Assignee: U-Blox AG (u-blox Holding AG)
• Original Assignee: U-Blox AG (u-blox Holding AG)
• Inventors: Yule, Andrew Thomas, Simmons, Ian Michael, Houldsworth, Richard James
• Application Number:
  US13/160,427
• Publication Number:
  US 20120306690A1
• Time in Patent Office: Days
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• CPC Class Codes: G01S 19/421 by combining or switching between position solutions or signals derived from different satellite radio beacon positioning systems; by combining or switching between position solutions or signals derived from different modes of operation in a single system

Abstract

A method of calculating a position fix from satellite signal samples. The method comprises: obtaining first reference information produced during the calculation (120a) of a first position fix, the first position fix being the calculated position of a satellite-positioning receiver (5) at a first time; obtaining second reference information produced during the calculation (120b) of a second position fix, the second position fix being the calculated position of the receiver (5) at a second time; receiving a set of satellite signal samples generated by the receiver at a third time, or ranging measurements derived from such a set of satellite signal samples; and processing (140) the set of samples or the ranging measurements to calculate a third position fix. The processing (140) is assisted by the reference information produced during the calculation of the first and second position fixes.

Claims

1. A method of calculating a position fix from satellite signal samples, the method comprising:

obtaining first reference information produced during the calculation (120a) of a first position fix, the first position fix being the calculated position of a satellite-positioning receiver (5) at a first time;

obtaining second reference information produced during the calculation (120b) of a second position fix, the second position fix being the calculated position of the receiver (5) at a second time;

receiving a set of satellite signal samples generated by the receiver at a third time, or ranging measurements derived from such a set of satellite signal samples; and

processing (140) the set of samples or the ranging measurements to calculate a third position fix,

wherein said processing (140) is assisted by the reference information produced during the calculation of the first and second position fixes.

2. The method of claim 1, wherein the processing uses knowledge of the first, second, and third times or one or more relative comparisons among them.

3. The method of claim 1, wherein each of the first and second reference information comprises at least one of:

the respective position fix;

a satellite-clock time associated with the position fix;

a clock-error between the satellite-clock time and a receiver-clock time;

a ranging measurement between the receiver and a satellite; and

an observed Doppler shift of a signal received from a satellite

4. The method of claim 1, wherein the assistance comprises predicting, based on the reference information at the first and second times, corresponding information at the third time.

5. The method of claim 4, wherein the prediction comprises interpolating or extrapolating a third value, corresponding to the third time, based on first and second values, corresponding to the first and second times, respectively.

6. The method of claim 4, wherein the prediction includes predicting the third position using an estimate of speed and/or direction of travel.

7. The method of claim 1, wherein the processing is further assisted by reference information produced during the calculation of one or more further position fixes, corresponding to other times.

8. The method of claim 1, wherein the assistance comprises choosing a parameter to be used in the processing.

9. The method of claim 8, wherein the parameter is an initial estimate of a ranging measurement or carrier frequency to be used in a despreading calculation.

10. A method of processing signals from a satellite positioning system, comprising:

receiving first, second, and third sets of data, each set comprising;

samples of satellite signals, obtainable by sampling (110) satellite signals at a satellite positioning receiver (5), or

ranging measurements derived from such samples,

wherein the first, second, and third sets of data correspond to first, second and third time-instants;

processing (120a, 120b) the first and second sets of data to derive respective first and second position fixes, in the course of which processing respective first and second reference information is produced (130a, 130b);

followed by

processing (140) the third set of data according to the method of claim 1.

11. A computer program comprising computer program code means adapted to control a physical computing device to perform all the steps of claim 1 if said program is run on a computer.

12. A satellite positioning receiver (5) comprising:

an RF front end (12), for receiving (100) satellite positioning signals;

an analogue-to-digital converter (18), for sampling (110) the received signals to generate signal samples;

a memory (22); and

a processor (20) adapted;

to process (120a) a first set of the samples, to calculate at position fix;

to process (120b) a second set of the samples, to calculate a second position fix; and

to store (130a, 30b) in the memory (22) first and second reference information produced in the course of the respective calculations,

wherein the processor (20) is further adapted to process (140) a third set of the samples, or ranging measurements derived from the third set of samples, to calculate a third position fix, assisted by the first and second reference information.

13. A satellite positioning receiver (5) comprising:

an RF front end (12), for receiving (100) satellite positioning signals;

an analogue-to-digital converter (18), for sampling (110) the received signals to generate signal samples;

a memory (22); and

a processor (20) adapted;

to process (120a) a first set of the samples, to calculate a first position fix;

to process (120b) a second set of the samples, to calculate a second position fix; and

to store (130a, 130b) in the memory (22) first and second reference information produced in the course of the respective calculations,

wherein the receiver (5) is further adapted to store a third set of the samples, or ranging measurements derived from the third set of samples, in the memory (22),

whereby the third set of samples or the ranging measurements can be later processed (140) to calculate a third position fix, assisted by the first and second reference information.

14. The satellite positioning receiver of claim 13, wherein the receiver is further adapted:

to retrieve the stored third set of samples or the ranging measurements from the memory (22); and

to process them to calculate (140) the third position fix,

wherein said processing (140) assisted by the first and second reference information.

15. The satellite positioning receiver of claim 13, wherein the receiver (5) is adapted to upload the first and second reference information and the third set of samples or the ranging measurements stored in the memory (22) to an external device (30), for processing them to calculate (140) the third position fix.