Research On Self-positioning Method Of Underwater Mobile Target Based On Received Signal Strength And Strap-down Inertial Navigation System

With the deepening of ocean exploration,the application of underwater acoustic self-positioning technology for underwater moving targets in underwater exploration,underwater rescue,underwater combat and other fields is increasing.Underwater acoustic self-positioning technology is mainly divided into active and passive.Because the passive underwater acoustic self-positioning technology has the characteristics of faster response speed,higher concealment and longer action distance than the active one,it is more applied in the actual underwater self-positioning system.At present,Strapdown Inertial Navigation System(SINS)positioning technology is one of the mainstream self-positioning technologies,but its inherent accunmulatjive error greatly affects the positioning accuracy of underwater moving targets.Therefore,this paper designed a new self-positioning technology for underwater mobile targets by reducing the accumulated error in SINS positioning,reducing the power consumption of underwater equipment and simplifying the hardware configuration.This paper mainly carries out research work from the following aspects:(1)The basic principle of underwater acoustic positioning is introduced,and the research status of the classic self-positioning method of underwater moving targets is investigated.In this paper,the propagation loss and absorption loss of underwater acoustic transmission are studied,and the differences between them under different frequencies of underwater acoustic signals are compared,which provides a theoretical basis for the design of a Received Signal Strength(RSS)model of underwater acoustic location based on the strength of received signals.(2)Considering that the propagation loss is the main source of signal loss in the low-frequency hydroacoustic signal,a ranging model based on RSS and SINS system is proposed.Combined with its own attitude information and the characte:ristics of underwater acoustic loss,the model can effectively eliminate the large measurement error of RSS and improve the ranging accuracy of the model in this paper by using the recursive algorithm of the moving state of the moving target.(3)According to the ranging model in this paper,a self-positioning method of RSS based on particle filter is proposed.This method calculates the signal intensity distribution information,constructs the mapping relationship between RSS information spatial distribution map and each transducer,integrates the mapping relationship between intensity and position into the improved particle filter algorithm,and realizes the location information solution.Simulation and experimental results show that the proposed method can effectively realize the self-localization of underwater moving target.(4)Aiming at the problem of low positioning accuracy when the number of effective beacons in the positioning system is relatively small,combined with the motion posture and speed of underwater moving targets,this paper designs a combined self-positioning method based on weighted least squares to solve the position information.The experimental results show that the accumulative error of SINS position is greatly reduced in the environment of a beacon position.