A variational mode decomposition projectile signal processing algorithm of infrared sky screen velocity measurement system and detection mathematical model of detection screen

Abstract

To improve the measurement accuracy of projectile initial velocity, this paper proposes a variational mode decomposition (VMD) projectile signal processing algorithm, and researches the detection mathematical model of detection screen. We establish the detection mathematical model of detection screen by combining projectile’s radiation, projectile’s size and the signal characteristics of projectile; analyze the contribution of projectile radiance to infrared photoelectric detector. Based on the time and space relationship that the projectile passing through the detection screen, we use the noise equivalent flux density to characterize the detection sensitivity of infrared sky screen to evaluate its detection performance and set up its time-space domain detection models; utilize the characteristic of the output signal of infrared sky screen to form a variational mode decomposition projectile signal processing algorithm, and use the cross correlation function to extract the time. By comparing the infrared sky screen and the traditional sky screen velocity measurement system with the standard net target velocity measurement system, it is evident that due to external interference, some velocity error values obtained by the traditional sky screen velocity measurement system are significantly different from those obtained by the infrared sky screen velocity measurement system. Without external interference, the average velocity error between the traditional sky screen velocity measurement system and the net target velocity measurement system is 0.47 m/s. Compared with traditional sky screen velocity measurement systems, the average velocity error of the infrared sky screen velocity measurement system and the net target velocity measurement system is slightly smaller, which is 0.32 m/s.