Applied Research On Projectile Motion Parameter Determination Using Geomagnetic Inducation Coil

The test of projectile motion parameters has an important significance to the development of smart munitions, measurement principle of projectile motion parameters by use of magnetic induction coil is studied, and a complete test system for the measurement of stable scanning parameters of terminal-sensitive projectiles(TSP) is designed.First, based on geomagnetic field theory and the International Geomagnetic Reference Model, change of the geomagnetic field intensity with latitude, longitude and altitude is simulated, it reveals that the geomagnetic field intensity remains unchanged within a certain range. Compared of several common geomagnetic sensor, then induction coil sensor is the chosen one.Second, the measurement principle of magnetic induction coil is discussed, and the equation of magnetic induction coil is obtained, it shows that the coil output voltage signal is related to attitude angle, attitude angle rate and fire direction. Trajectory simulation to spinning projectile indicates that the measurement results of magnetic induction coil are affected by different fire direction. Then the measurement model of stable scanning parameters of TSP is further established, to measure the scan angle and scanning velocity of TSP.Third, the measurement system of stable scanning parameters of TSP is designed, it includes stable scanning parameters recorder and the user software. In the recorder, the signal acquisition, AD sampling, data recording, USB interface communication to PC are involved. The user software's function consists of USB interface communication, data read, data reduction, etc.Some data reduction methods are studied in the user software, consist of Butterworth filter design, the calculation of scan angle and scanning velocity. To the problem that the scan angle can not be got with the measured saturation signal in the past, the derivative calculation method of data reduction based on the Savitzky-Golay method is put forward, and the simulation test results are given.Finally, experimental tests demonstrate the measurement system can effectively measure the stable scanning parameters of TSP.