Navigation Method For UUV Work/sleep State Switching

High precision navigation and positioning system is the key to ensure each task can be accurately performed by Unmanned Underwater Vehicle(UUV).However,Dead Reckoning(DR)and Inertial Navigation System(INS)will produce a large number of cumulative error,when UUV long-term long-range voyage,which is the main cause of UUV navigation error.Therefore,in order to improve the accuracy of navigation and positioning,the research of underwater navigation and positioning method of UUV is important.Aiming at the special situation that UUV needs to keep sitting state at any set time and sea area for a long time,the paper analyzes the causes and calibration methods of the navigation error before and after UUV sit on bottom.And designs the UUV work / sleep state switching system,which can achieve the state of UUV switched between the working state and the sleeping state.Under the premise of ensuring UUV concealment and achieve navigation error calibration,the study of the relevant underwater acoustic navigation and positioning methods.According to the special situation that UUV needs to keep sitting state at any set sea area,a UUV navigation position calibration method by the preset underwater acoustic beacon is proposed.The Underwater Locator Beacon(ULB)is pre deployed by the surface ship,after the successful deployment the position of the beacon can be regarded as accurately known,and introduced the principle of beacon assisted UUV navigation positioning.During the process of beacon assisted UUV navigation position error calibration,the relative distance between beacon and UUV as the observation information,the UUV value of current position can be estimated by nonlinear filtering algorithm,so the nonlinear filtering algorithm for the beacon assisted UUV navigation has been demonstrated in detail.Through the simulation analysis to compare the filtering effect of Unscented Kalman Filter(UKF)with Cubature Kalman Filter(CKF),which used for the acoustic navigation and positioning,the result showed that: UKF has high accuracy under the condition of zero mean noise.Because observation noise is time-varying in the actual marine environment,variational Bayesian Unscented Kalman Filter is proposed,which is suitable for DR/ULB Integrated Navigation System,the simulation shows that the algorithm can estimate observation noise accurately and efficiently.Through the further research of the navigation method of UUV work / sleep state switching,the method can improve the accuracy when UUV perform the task keeping sitting on the seabed in the complex marine environment,and provide a reliable guarantee for othernavigational tasks.It has great theoretical significance and application value for long distance navigation mission of UUV and reconnaissance mission in the set sea area.