A nonlinear two-filter smoothing estimation method based on DD2 filter for land vehicle POS

Land vehicle position and orientation systems (POSs) are playing an important role in ground surveying. In order to solve the problem of nonlinear error and obtain high-precision motion parameters in post-processing, a nonlinear two-filter smoothing estimation method based on second-order divided difference filter (DD2) for land vehicle POS is proposed. The DD2, based on Stirling interpolation, is applied to solve the nonlinear problem in the forward filter. The information filter is adopted to independently estimate the states and error covariance matrices in the backward filter. Then the forward and backward results are combined, which makes full use of all measurement information and also uses more model information. Therefore, more accurate estimation results for the POS can be obtained. Finally, an experiment is carried out, and the results show that the attitude precision of a land vehicle POS can be effectively improved through the proposed method. (paper)