一种顾及厄特沃思效应的水下重力辅助导航方法

An Underwater Gravity-aided Navigation Method Considering the E?tv?s Effect

水下相对于水面环境,准确估计厄特沃思效应更为困难,进而影响重力测量精度。由于传统重力匹配算法未考虑水下厄特沃思估计误差对重力辅助导航定位性能的影响,根据不同导航参数对厄特沃思估计误差的影响程度,构建了水下惯导系统/计程仪/重力仪组合导航框架,采用UKF非线性滤波算法,分析了不同导航模式下厄特沃思估计误差特性,并评估了有无厄特沃思估计误差时重力辅助导航性能的差异。半物理仿真结果表明采用DVL的辅助导航方式可有效抑制惯导误差积累,INS/DVL/Gravimeter三者信息融合导航模式定位性能得到了进一步提高,即使在考虑厄特沃思估计误差的情况下,与仅采用DVL作为辅助信息源相比,水平径向误差定位精度依然提升了17.02%。

Compared with the surface of the water,it is more difficult to accurately estimate the E?tv?s effect in underwater,which affects the accuracy of gravity measurement.The traditional gravity matching algorithm does not consider the impact of E?tv?s estimation error on the performance of gravity aided navigation.Aaccording to investigating the degree of influence of different navigation parameters on E?tv?s estimation error,establishes inertial navigation system(INS),Doppler velocity log(DVL)and gravimeter underwater navigation framework based on unscented Kalman filtering(UKF).The performance of gravity aided navigation with or without E?tv?s estimation error is evaluated.Semi-physical simulation results show that the DVL underwater aided navigation method can restrain the accumulation of INS errors to a certain extent.The positioning performance of the INS/DVL/Gravimeter navigation mode is further improved.Even when the E?tv?s estimation error is considered,the horizontal radial positioning accuracy is still improved by 17.02%compared with only using DVL as the aided information.