Patent ID: 6163754
Filing Date: 2000-12-19
Classification: G01S

Abstract:
A method for estimating a line bias for a signal received from a common signal source at each of two or more signal receivers, the method comprising the steps of:(i) receiving and measuring a signal from a carrier phase signal source at each of first and second signal-receiving stations, denoted station ""A1"" and station ""A2"", and forming a difference signal value LB(t.sub.n ;A1;A2) from a first signal and a second signal received at the respective first and second stations from the carrier signal source;(ii) providing an initial value for a line bias;(iii) estimating a line bias variation that is a difference between the difference signal value and the initial line bias value for each of a sequence of at least two selected times t=t.sub.n ;(iv) passing the estimated line bias variation values through a selected smoothing filter to produce a smoothed line bias variation;(v) using a sum of the smoothed line bias variation and the initial line bias value to provide a forward estimate for line bias for at least one selected time interval t.sub.n .ltoreq.t<t.sub.n+1 ;(vi) determining a least squares optimal solution for at least one unknown variable value in a single difference solution involving measurements of carrier phase signals from each of two or more carrier signal sources, compensated for line bias; and(vii) replacing the time index n by n+1 and repeating steps (i)-(vi) at least once.