Research On Underwater Projectile Positioning Measurement Technology Based On Magnetic Sensor

The testing of underwater projectile speed and motion trajectory is an important indicator for judging the stability of the projectile in water.However,it is limited by the influence of comprehensive factors such as the underwater environment and cavitation around the projectile,and effective testing methods are relatively lacking.For projectiles made of magnetic materials,the underwater projectile positioning and measurement method based on magnetic sensors can overcome the influence of water environment on projectile testing,and better realize the speed and movement trajectory test of projectiles in water.Based on the analysis of the magnetic nail magnetic field model,Matlab was used to simulate the magnetic field around the projectile,and the relationship between the magnetic induction intensity and distance that can be used for distance measurement was summarized;the magnetization method of the projectile was compared,and the appropriate Types of projectiles;the influence of the water environment on the magnetic induction intensity is analyzed,and it is verified that the underwater projectile positioning method based on the magnetic field has strong anti-interference ability in the water environment.Aiming at the problem that different projectiles have different magnetic sensing requirements,a double-ring zone intercepting target structure is proposed.After comparing the advantages and disadvantages of various magnetic sensors,a TMR magnetic sensor suitable for projectile positioning is selected.According to the projectile's flight speed and sensor background For noise and other factors,a high common-mode rejection ratio circuit,a low-pass filter circuit,an amplifying and zeroing circuit,an analog-to-digital conversion circuit and a communication circuit are designed,and the calculation method of the key parameters of each circuit is given.Through the projectile magnetic signal detection experiment,the effectiveness of the magnetic sensor system is verified.By analyzing the impact of hysteresis and geomagnetic field interference on the output of the magnetic sensor system,a solution to the difference preprocessing is proposed.Through distance calibration,the mapping relationship between the output voltage of the magnetic sensor system and the distance between the projectile and the sensor base station is established;The wave peak detection algorithm is used to improve the accuracy of the detection trigger time;the underwater projectile positioning algorithm is determined by the RSS method based on least squares.The experimental equipment used in the calibration experiment and the positioning experiment are introduced,the results of the calibration experiment are analyzed,and the fitting results of each fitting function are compared,and the appropriate fitting function is selected;the calibration experiment results and positioning are given The experimental results of the experiment are analyzed;through the analysis of the results of different water turbidity and different water temperature positioning tests,it is shown that the magnetic sensor system and positioning algorithm are feasible,and the positioning has high stability in different water environments.