Information fusion of integrated navigation based on self-adaptive filter

In order to realize high accuracy and excellent reliability of navigation system, information fusion technology of integrated navigation based on self-adaptive filter is researched in this paper. Inertial navigation system (INS), global navigation satellite system (GNSS), synthetic aperture radar (SAR) and barometric altimeter (BA) are taken to construct INS/GNSS/SAR/BA integrated navigation system. INS is regarded as the primary navigation equipment, and other systems are aided navigation equipments. Firstly, errors of INS, GNSS, SAR and BA are modeled and chosen as system states of integrated navigation. Based on self-adaptive filter algorithm, output information of INS and GNSS are fused in INS/GNSS integrated navigation filter, and output information of INS, SAR and BA are fused in INS/SAR/BA integrated navigation filter. Then the federated filter frame is designed, and estimations of system states from INS/GNSS and INS/SAR/BA local filters are fused once more in the master filter independently. Consequently global optimal estimations of system states are given by the master filter, which are used to correct errors of INS. Simulation results show that, position accuracy of INS/GNSS/SAR/BA integrated navigation reaches ± 11.6m, attitude accuracy reaches ±0.52′, velocity accuracy reaches ± 0.14m/s, and its reliability is very excellent when noise statistics characteristics of some navigation equipment are variational in the navigation process.