The Design and Realization of A New Double Smoothing Filter Algorithm

Abstract—Global Navigation Satellite System is the most important infrastructure to compass the way nowadays and in the future, and the carrier smoothing code method is usually used to improve the accuracy of the position. However, there will be a great influence on satellite navigation and positioning with abnormal ionospheric fluctuations. The filtering divergence problem caused by carrier smoothing code under the abnormal ionospheric conditions is researched in this paper. Then a double smoothing filtering algorithm based on a low pass filer is proposed. This algorithm can improve the positioning accuracy and avoid the filtering divergence through optimizing the smoothing window. Analysis results show that the algorithm proposed by this paper has advantages in two aspects: one is that it can restrain the output noise level of the double smoothing code filter and enhance the detection sensitivity of the abnormal ionosphere fluctuations; on the other hand, the double smoothing code filter can select the optimal smoothing window through the detecting results of the abnormal ionosphere fluctuations, and it can improve the positioning accuracy and avoid the filtering divergence.