An adaptive Hatch filter to minimize the effects of ionosphere and multipath for GPS single point positioning

Though the traditional Hatch filter can be used to improve positioning accuracy by reducing receiver noise in code pseudorange, the filtered errors could diverge because of the effects of ionosphere and multipath. Based on analyzing the positioning error caused by ionosphere temporal and spatial gradients and multipath effects, a novel algorithm to design the adaptive Hatch filter with optimal weighting factor is put forward in this paper. The optimal weighting factor is derived from the filtered total error variance. Analysis on the experimental results of static and kinematic position shows that this kind of adaptive Hatch filter can provide a more accurate and robust position results than the traditional Hatch filter.