Data Link Communication Signal Blind Processing And Implementation Technology

The data link communication signal is mainly used for data exchange and communication between the aircraft and the control center.Compared with the traditional radio communication method,the data link communication method is more advanced,has higher confidentiality,and is not easy to be detected by other equipment.Data link signals have the characteristics of large transmission capacity,random frequency hopping,random time hopping,and high positioning accuracy.They are often used in modern electronic warfare.In high-tech electronic warfare,how to perform fast parameters on the data link signals received? Blind processing and parameter estimation are of great significance.This design mainly includes two parts.The first part is to generate data link simulation signals with frequency hopping,GMSK modulation and other characteristics by using MATLAB.According to the characteristics of the signal,a corresponding algorithm is designed to complete the correlation processing of the signal.The processing contents include digital channelization of the signal,array direction finding,beamforming,precise estimation of time,identification of signal modulation,and time-frequency parameter estimation.On the premise of algorithm simulation,the hardware implementation part of the second part is carried out,and the simulation algorithm is transplanted into the multi-core digital signal processor(DSP).In order to improve the real-time performance,further optimization of the transplanted algorithm and hardware implementation strucure was made.The traditional single-core implementation was changed to a multi-core parallel pipeline implementation to ensure that every data received.The pulse can complete the process of receiving and blindly estimating the parameters,which can ensure that the processing time of each core is within tens of microseconds and achieves the high-speed parallel processing.The research contents of blind processing system for data link communication signals in this paper are as follows:1.Parameter analysis of data link communication signals is performed,and the overall system scheme is designed based on the characteristic information.And briefly explain the implementation method of each module in the scheme.2.The channelization process is implemented by a polyphase digital filter bank,and the filter bank is improved.An IDFT-based scheme is proposed to achieve an efficient digital channelization process.Compared with the traditional channelization scheme of multiple band-pass filter banks,the digital channelization structure has a smaller amount of computation and complexity.By setting the filter bandwidth,the signal decimation ratio and the filter overlap ratio can ensure the seamless connection of the signal in the entire bandwidth,ensuring the full probability of signal reception and processing.3.In the blind processing part of the data link signal,the signal preprocessing process is needed first,so that the signal parameter estimation result is more accurate.The RootMUSIC algorithm is used to estimate the incoming signal direction and the number of signals,and adaptive beamforming is performed according to the incoming signal angle of different signals to suppress interference signals.A method for finding the coordinates of energy inflection points in the energy accumulation curve is proposed in the time precision estimation of data link pulses.On the signal modulation recognition algorithm,a method based on higher-order spectral line characteristic analysis is proposed to identify the modulation mode of the signal.The algorithm is used to distinguish the modulation modes of GMSK,MSK,and OQPSK signals.The parameter blind estimation part estimates the signal's center frequency,bandwidth,baud rate and other parameters through the squared line spacing and oversampling ratio of the signal.4.In hardware implementation,the simulation algorithm is transplanted to a multicore DSP chip for implementation.By using inline functions,the loop is unrolled and register variables are used.Other means reduce the clock cycle of DSP processing.Adopt a multi-core parallel pipeline structure and use the MessageQ structure in the IPC core communication module of the DSP to complete the core-to-core information transfer.The introduction of a semaphore mechanism restricts the core and core from accessing shared area variables at the same time,avoiding processing the deadlock phenomenon occurs,and the timing problem of signal processing is strictly controlled.Realize the processing effect of high-speed parallelization of data link signals.Finally,the algorithm was tested on the hardware platform in real-time and performance.Through the actual hardware system test,the algorithm can ensure the real-time performance of the data link signal processing and the accuracy of signal parameter estimation.