Navigation processing for a satellite positioning system receiver

• US 6,665,612 B1
• Filed: 08/29/2001
• Issued: 12/16/2003
• Est. Priority Date: 08/29/2000
• Status: Expired due to Term

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Tuck, David Allan, Chansarkar, Mangesh M., Brodie, Keith Jacob
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Donnelly, Arthur D.
• Application Number:
  US09/943,071
• Time in Patent Office: 839 Days
• Field of Search: 701/213, 701/207, 701/214, 701/215, 342/357.02, 342/357.03, 342/357.06, 342/357.12, 702/153
• US Class Current: 701/213
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks

Abstract

A method for navigation processing in a satellite positioning system receiver is disclosed. A method in accordance with the present invention comprises separating the three SATPS satellites into a first pair and a second pair, constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints, computing a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solution, computing Doppler difference residuals for the first pair and the second pair of SATPS satellites, and comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution. Typically, the computing of a Doppler difference residuals comprises differencing a measured Doppler difference from an estimated Doppler difference for the first pair and the second pair of SATPS satellites. Typical determination of a valid solution comprises comparing the difference between the Doppler difference residuals to a predetermined number. Usually when the Doppler difference residuals exceed the predetermined number, the alternate solution is selected as the valid solution.

Claims

1. A method of verifying the validity of a SATPS three satellite solution, comprising:

separating the three SATPS satellites into a first pair and a second pair;

constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints;

computing a Doppler difference estimate for the primary solution and a Doppler difference estimate for the alternate solution;

computing Doppler difference residuals for the first pair and the second pair of SATPS satellites; and

comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution.

2. The method of claim 1, wherein the computing of a Doppler difference residuals comprises differencing a measured Doppler difference from an estimated Doppler difference for the first pair and the second pair of SATPS satellites.

3. The method of claim 2, wherein the determination of a valid solution comprises comparing the difference between the Doppler difference residuals to a predetermined number.

4. The method of claim 3, wherein when the Doppler difference residuals exceed the predetermined number, the alternate solution is selected as the valid solution.

5. A method of verifying the validity of a SATPS three satellite solution, comprising:

separating the three SATPS satellites into a first pair and a second pair;

constructing a primary solution and an alternate solution, wherein the primary solution and the alternate solution satisfy the measurement constraints;

computing a Doppler difference estimate for the first pair and the second pair of both the primary and alternate solutions;

computing Doppler difference residuals for the first pair and the second pair of SATPS satellites in each solution by subtracted measured doppler differences from the doppler difference estimates; and

comparing the Doppler difference residuals for said primary and alternate solutions to determine a valid solution.