Research On Cooperative Sensing Technology Of Underwater Unmanned Multiple Sources

The detection performance of bistatic / multistatic sonar system is generally better than that of monostatic sonar system,but at the same time,the bistatic / multistatic sonar system needs to face the problem of multi-source signal field conflict.For example,the receiving platform of multistatic sonar may receive target echoes from different transmitting platforms at the same time,at this time,these target echoes become mutual interference,which affects the detectability of multistatic sonar system Yes.In order to reduce the influence of echo interference on detection,this paper mainly studies code domain channel multiplexing and spatial channel multiplexing.Based on the principle of code domain channel multiplexing and the weak correlation between signals,the multi-source signals are designed based on the principle of high identification and low interception.The time delay,frequency shift resolution and anti reverberation ability of the designed signal are analyzed by fuzzy function and Q function.The active detection ability of the receiving platform for various signals is analyzed and compared by using the bistatic active detection model.The simulation results show that the receiving platform has better active detection ability for m-sequence signal,tent chaotic signal and improved Logistic chaotic signal.The passive detection model of underwater acoustic pulse with unknown parameters is used to analyze and compare the low interception ability of various signals.The entropy detection method,instantaneous correlation integration method and timefrequency analysis method are used to detect various types of signals.Different types of signals have different low interception performance under different detection methods.Through the simulation analysis of autocorrelation function and cross-correlation function,it is found that the m+Costas combined signal and the improved Logistic chaotic signal have good weak crosscorrelation,which can be used as multi-base multi-source resolution signal.In order to realize the spatial multiplexing technology of multistatic sonar,this paper uses non-uniform array to reduce the side lobe level of array beam output and reduce the influence of interference on detection.Based on the principle of spatial channel multiplexing,this paper first studies the spatial gain of conventional array sonar array,and analyzes the main performance parameters of the array beam output,such as the main lobe width and the maximum side lobe level.Particle swarm optimization(PSO)is used to optimize the position of circular array elements.With the same number of array elements,the optimization of side lobe level is realized under the condition of a certain main lobe width.In addition,compared with the conventional array,the direction of the peak of the end beam does not change with the distance.Finally,combining the designed multi-source resolution signal with the optimized array,a multi-source interference free cooperative sensing model is constructed,and the output results of sonar system with different incident signal number,different wave direction and different signal-to-noise ratio are studied.The simulation results show that the interference free cooperative sensing model can reduce the influence of multi-source echo interference on the performance of multistatic detection.