| The lightning detection system plays a key role in the lightning disaster prediction and prevention,and this paper mainly studies the lightning detection system for multi-channel signal receiving and processing method in the FPGA.After proposing the data pre-processing process of the lightning detection system and the functions and requirements of each module, this paper analyses the multi-channel high speed signal receiving module. It discusses the process and method of receiving the lightning signal by antenna array. Then the receiver's performance of the module is analyzed, from which this paper can confirm that the performance of the ADC receiver module has met the requirements.In order to extract thunder signal for data analysis and processing, in the following subsequent process of data pre-processing, this paper focuses on the detection of lightning signal. In this part, by studying the features of the lightning signal and noise environment, this paper proposes the corresponding constant false alarm algorithm for detection, and makes improvements according to the practical demands of the system. And then it shows how the algorithm is realized in the FPGA after the detection threshold is determined.Next, to reduce the pressure of the data processing and transmission, this paper studies the adaptive quantization processing method for the effective signal. In this part, compared with the closed-loop AGC method, the open-loop control method is proved to be more suitable for the system.Finally, after the quantization process, in order to use the MUSIC algorithm, this paper expounds and realized the covariance matrix. Considering of the traditional covariance calculation method, this paper makes research of a new covariance calculation method based on the covariance matrix of real number. After comparing the two methods, it confirms that the system using the real number methods to calculate covariance is much more suitable. |
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