Gravity Gradient-Geomagnetism Combined Aided Underwater Navigation Using Federated Information Fusion

Abstract

Geomagnetic and Gravity aided navigation ways are equally important in the field of underwater navigation. However, geomagnetic aided navigation method is sensitive to the time-vary noises and gravity aided navigation method is affected by fluctuation of a terrain. Considering an important character that gravity gradient vector could avoid the influence from time-vary noises and is less sensitive to the fluctuation of a terrain, the geomagnetic and gravity gradient vectors are combined together to adopt merits of each aided navigation method. Geomagnetic and gravity gradient vectors are used as measurement information from both local UKF filter, then a federated information fusion algorithm is to combine estimated values from each local filter to form a optimal estimated state value. Finally, the optimal estimated value is used to update output values from each local UKF filter. The experimental results prove the feasibility of such integrated navigation method.