Study Of Background Magnetic Field Model And Geomagnetic Attitude Measurement On Spinning Projectile

With the continuous improvement requirements of ammunition firing accuracy and the development of all kinds of intelligent ammunition, accurate measurement of the projectile flight attitude parameters has become the urgent task. It can improve the performance of weapon and develop the national defense science and technology.Achieving attitude measurement of projectile with geomagnetic measuring has good characteristics, such as no source, no radiation, all-time, all-weather and low energy consumption. It has become the development trend of the projectile attitude measuring methods. At present, all the methods giving orientations with respect to geomagnetic field are faced with the interference of background magnetic field. Meanwhile, the three axis components of the geomagnetic cannot give the whole attitude information. These problems make this technology to be still auxiliary in the carrier attitude measurement.The interference mechanism and characteristic of rotating projectile background magnetic field are analyzed. A mathematical model of background magnetic field is built and the researches of modeling compensation technology for magnetic measuring on projectile are carried out. An attitude measurement method is designed based on full magnetic sensor combination. Reasonable configuration and calculating method are discussed. On the basis, the test system software and hardware design are accomplished. The hardware-in-the-loop simulation of the developed measuring device is carried out to verify the effectiveness of the proposed design. Main research work can be summed up in the following aspects:(1) The mathematical modeling of rotary projectile background magnetic field is studied based on the interference mechanism analysis. Combined with the self-error characteristics of magnetic sensor, the comprehensive compensation model of magnetic survey is built and modeling compensation method is put forward.(2) The separating estimation method of the compensation model coefficients is researched. The qualities of four identification algorithms for static model coefficients are studied. The optimization design of the dynamic eddy current compensation coefficients estimation is accomplished. The effectiveness and reliability of the proposed methods are verified by the simulations and experiments.(3) The three orthogonal ratio method is put forward for measuring projectile attitude. Combining with the proposed modeling compensation technology, a new attitude correction method with full magnetic sensor unit is designed, which has all-time, all-weather measuring capability and is suitable for rotating projectile. (4) Data acquisition system with FPGA microprocessor control is designed for geomagnetic measurement. This system works in data storage and recovery mode, and suitable for both turntable experiment and the missile-borne experiment.(5) The hardware-in-the-loop device is developed for the experiments, which are carried on using three-axis turntable. The results show that calculating errors are within±1°.