Method and system for position calculation from calculated time
AssigneesSeiko Epson Corporation, eRide, Inc.
InventorsStephen J. Edwards, Paul W. McBurney
Life of this patent
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Abstract
A navigation-satellite receiver comprises means for initialization that gets a head start by knowing time to within a few seconds and position to within 150 kilometers. A two-dimensional grid of points is setup with constant altitude that represents solution starting points within the 150 kilometer area. Fractional pseudoranges from each satellite in a constellation are inspected for a best initial fit with the points in the grid. A variety of time bias adjustments within the time bounds are also tried against the points to find a best fitting point. That point then is used in a drive to find the final solution and to produce the first fix from cold start.
Claims25
A navigation satellite receiver method, the method comprising the steps of:
- not using z-count and assuming time is known to within a few seconds;
- assuming position is known to within a few hundred kilometers;
- creating an imaginary grid of points that could lie within the uncertainties of said time and position assumptions;
- and
- using partial pseudoranges, without knowing the solution to the integer ambiguity problem, to find particular points in said grid of points that fit best with regard to said time and position assumptions;
- wherein, a best-fitting point is used iteratively to find a final solution and to produce a first fix from cold start.
Dependencies are inferred from the claim text.