Research And Software Implementation Of Signal Parameter Estimation Method For Non-cooperative Underwater Acoustic Communication

In modern three-dimensional underwater warfare,the reconnaissance and countermeasure technology of underwater acoustic signal occupies an important position.Communication reconnaissance provides technical support for information interception and countermeasure.The main purpose of the non-cooperative underwater acoustic communication parameter estimation method studied in this paper is to provide the input of the communication signal estimation parameters for the underwater acoustic communication countermeasure system,which is the precondition for effective interference.In this paper,three common communication system parameter estimation methods,single carrier,direct sequence spread spectrum(DSSS),orthogonal frequency division multiplexing(OFDM),are studied.For single-carrier communication system: carrier frequency estimation method is studied using frequency domain and wavelet transformation,and symbol rate estimation is studied based on multiscale wavelet transformation.Cyclic spectral slicing,which can simultaneously estimate carrier frequency and symbol rate,is also studied.For direct sequence spread spectrum communication system,carrier frequency estimation methods based on square frequency doubling and square correlation are studied.The PN code rate estimation method based on delay multiplication and wavelet transformation is studied.For PN code period estimation,time-domain autocorrelation method and secondary power spectrum method are studied.For OFDM communication system: For joint estimation of symbol length and total symbol length,autocorrelation and pseudo-inverse spectral methods are studied.For each parameter estimation method above,the anti-noise and real-time performance of the algorithm are compared by computer simulation.On this basis,the performance of the algorithm is further verified by sea test data in different sea areas.The experimental data processing results show that the real-time performance of the frequency domain centering method in the carrier frequency estimation algorithm is much better than other carrier frequency estimation algorithms in single carrier communication system,and the real-time performance and accuracy of the multiscale wavelet transform method in the symbol rate estimation algorithm are better.In direct spread spectrum communication system,the square correlation method in carrier frequency estimation algorithm has better anti-noise performance,the accuracy and real-time of the wavelet transformation method in PN code rate estimation algorithm is better,and the second power spectrum method in PN code period estimation algorithm has better anti-noise and real-time performance.In the joint estimation algorithm of symbol length and total symbol length for OFDM communication,the pseudo-inverse spectral method performs better in realtime performance and in sea test data processing.After the comparative analysis of the above algorithms,the optimal parameter estimation method is selected from the above algorithms,and the optimization algorithm is programmed through the IPP library and C++.Based on the scenario,software-related functions are designed and implemented using C++ and QT.