Resolving time ambiguity in GPS using over-determined navigation solution

• US 6,618,670 B1
• Filed: 09/14/2001
• Issued: 09/09/2003
• Est. Priority Date: 09/15/2000
• Status: Expired due to Term

• Current Assignee: CSR Technology Incorporated (Qualcomm, Inc.)
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Chansarkar, Mangesh M.
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US09/952,548
• Time in Patent Office: 725 Days
• Field of Search: 701/207, 701/213, 701/214, 701/216, 701/215, 342/357.01, 342/357.04, 342/357.06
• US Class Current: 701/213
• CPC Class Codes: G01S 19/42 Determining position

Abstract

The invention describes methods and apparatuses for determining a user position based on a minimization of the errors introduced into the GPS system because of clock bias, noise, multipath, or other uncertainties. By overdetermining position, for example, clock biases can be removed from the system.

Claims

1. A method for resolving a variable ambiguity in a global positioning system receiver, comprising:

determining a plurality of pseudoranges to a plurality of Global Positioning System satellites;

an error range for each of the pseudoranges, wherein the error range gives a maximum and a minimum for each of the pseudoranges; and

minimizing a distance from a predetermined estimate of user position to the maximum and minimum for the plurality of pseudoranges.

2. The method of claim 1, wherein a variable ambiguity is known.

3. The method of claim 2, wherein the variable ambiguity is a clock bias.

4. The method of claim 1, wherein minimizing is performed by minimizing a sum squares of residuals from the estimate of user position.