Patent ID: 6268823
Filing Date: 2001-07-31
Classification: G01S

Abstract:
A method for determining a position of a platform using a set of range measurements between said platform and a set of known positions, said method comprising the steps of:(a) relating an estimate of the error in an assumed state of said platform to a set of measurement residuals;wherein said assumed state includes an assumed position of said platform and an assumed bias which is the same in each element of said set of range measurements;and wherein each element of said set of measurement residuals is the difference between an actual range measurement and a predicted range measurement;and wherein one said actual measurement determines the distance between an actual position of said platform and one said known position;and wherein each said actual measurement includes an actual bias which is the same for each element of said set of range measurements;and wherein said predicted range measurement is a distance between said predicted position of said platform and one said known position; and(b) updating said platform state estimate by substituting the difference between the square of said range measurement and the square of the distance from said position of said platform to said known position to which said range measurement corresponds, each difference divided by twice a distance between said predicted position of said platform and said known position, for each of said measurement residuals in said step (a).