Technologies Study Of Signal Processing For Measuring The Interior Ballistic Velocity

The motion parameters measurement of an artillery interior projectile is one of the most important content in the field of interior ballistic measurement. The microwave interference measuring technology is an effective method in interior ballistic measurement. It calculates the variation of projectile velocity with time in artillery trajectory by the analysis of the Doppler echo signal that is generated by microwave interference and related to the moving projectile. Then it can get other parameters of an interior ballistic projectile, e.g., the acceleration, the stress and so on. These parameters provide data support for designing the artillery barrel and the projectile charging system, furthermore, they play a key role in evaluating the artillery in safety and reliability.This thesis conducts a study on several technologies of signal processing in a microwave interference measurement system, and emphatically resolves the signal conditioning circuit design, signal denoising method and frequency calculating algorithm. Firstly, this thesis designs and achieves the core signal conditioning circuit including the Programmable Gain Amplifier (PGA) circuit and the two-order Bessel active low-pass filter. Then it debugs them. Secondly, this thesis applies the denoising algorithm for the Doppler frequency shift echo signal that combines Coiflets wavelet with Empirieal Mode Decomposition (EMD) and achieves a favorable denoising result when the Signal to Noise Ratio (SNR) of the simulated signal is higher than-5dB. Finally, this thesis discusses and proposes a velocity measurement algorithm for the interior ballistic projectile based on the Hilbert Transform (HT). Then it conducts the frequency estimation on several simulated Doppler frequency shift signals. Estimation results show that the speed solver relative error is less than0.16%when the velocity of the target object is higher than28m/s and the SNR is higher than OdB. The achievements mentioned above have already been used in XX Microwave Interferometer. Preliminary results show that the hardware circuit is reasonable, the algorithm is correct, the frequency solver relative error is even less than10-4for the point-frequency simulating source signal and the overall performance is perfect. In other words, the achievements satisfy the practical application requirement.