Research On Speed Measurement And Transient Information Data Processing Method Of Projectile Motion Process

With the rapid development of military technology,it is very important to study the methods of parameter acquisition and data processing in this field.The extraction of transient information of each signal in data processing has always been a hot research direction.Based on this background,this paper studies the transient information according to the test data obtained by the subject.Firstly,aiming at the problem of difficult acquisition of signals in harsh environments,a speed measurement system is designed by using thin-film coil geomagnetic sensor and based on ballistic storage testing technology.Through practical application,the external ballistic speed signal of projectile is obtained.Then,the test data involved in this paper have the characteristics of non-linearity and non-stationarity.By analyzing the data processing method of this kind of signal,Hilbert-Huang transform(HHT)is chosen as an effective algorithm to solve this kind of signal.Secondly,the method of solving instantaneous frequency is applied to speed signal by using MATLAB software.An analog projectile speed signal is constructed,and the instantaneous frequency curve of the projectile is obtained by using HHT.For the endpoint effect of instantaneous frequency curve,the method of signal continuation is adopted.Finally,three groups of measured projectile speed signals are selected as the research object,and the instantaneous frequency of each group of speed signals is calculated.The core of HHT is EMD decomposition.EMD decomposition is to decompose multi-component signals into single-component signals.It is not physically meaningful to obtain the average value of multiple single-component signals directly from the transient state of multi-component signals.In this paper,we do further research on the decomposed single component signal to find its transient value,and prove that the obtained transient value is of physical significance and research value for the original signal.Three groups of measured projectile rotational speed signals were selected as the research object.In each data,EMD decomposition is performed to obtain the corresponding IMF components,and the instantaneous frequency of each component is calculated.After analysis,the instantaneous frequency value obtained by using a certain IMF component is basically the same as the predicted value.To further prove its feasibility,the main frequency components of the instantaneous frequency curve corresponding to the original signal accounted for more than 98% of the total signal frequency energy by using the Passeval theorem.The feasibility of this method is verified by calculating the instantaneous frequency of the speed signal.The instantaneous value obtained by this method is representative,and the method of calculating the instantaneous frequency of the speed signal has research value.