Patent ID: 8451168
Filing Date: 2013-05-28
Classification: G01S

Abstract:
1. A method for determining biases of satellite signals emitted by satellites of a satellite navigation system and received by reference stations comprising the acts: satellite signals of the satellites are received by a plurality of reference stations, systematic instrumental errors based on the satellite signals received from the satellites are determined by using a recursive state estimator, and while determining the systematic instrumental errors, separate, individual values for instrumental code biases and instrumental ambiguity-free phase biases of the satellites and reference stations are determined by using the recursive state estimator, which determines the biases: wherein the code biases and phase biases of the satellites and reference stations are determined on at least two frequencies; wherein in the recursive state estimator selected biases are mapped into the ranges and into the ionospheric delays, selected biases of one satellite are mapped to the biases of the reference stations, and a subset of integer ambiguities are mapped to the phase biases; and wherein a multi-stage recursive state estimator is used, the first stage recursive state estimator estimating ranges, range rates, ionospheric delays, unmapped biases of the reference stations and satellites, as well as ambiguities, the last stage estimating the positions of the satellites, satellite velocities, tropospheric zenith delays, as well as the unmapped biases of the reference stations and satellites, and wherein a selection of the floating ambiguities is fixed before the last stage recursive state estimator.