The Research For Time-delay Estimation Of Lightning Pulse And Related Technologies

Researching lightning detection and localization plays a key role in energy, power,communication, defense security, aerospace, forecast, meteorology and other industries.Base on this background and correlative requirements, this dissertation mainly studies the time-delay estimation of the lightning pulse and the data compression technologies which is introduced to improve the efficiency of the time-delay estimation in whole. As one of the key technologies of passive location, the accuracy of the pulse time-delay estimation largely determines the accuracy of the passive positioning system. Fast and accurate time delay estimation is an important issue of the TDOA location system.Firstly, this article studies the time delay estimation method based on Generalized Cross-Correlation algorithm and analyzes the influence of different weighting functions on the anti-interference capacity of this algorithm and the accuracy of the time delay estimation through simulation. Then the part analyzes the realization of the time-delay estimation algorithm in aspects of homologous pulse-pairing and time-delay estimation.Finally, this part tests the calculation speed and accuracy of the system by two-station fixed-emitter experiments and multi-station mobile-emitter experiments, which has some practical value.In order to reduce the load of the lightning data transmission system and make the delay estimation and positioning of the whole lightning system more real-time, the second part of this article studies data compression technologies in the time-delay estimation system. The data compression scheme is divided into two steps as foremost lossy compression and secondary lossless compression. About lossy compression, this part mainly studies the Bit-compression method and transform method in wavelet domain,introduces the principles of these two methods, verifies the effectiveness of these two algorithms using a series of compression simulations for a large amount of lightning impulses under the premise of ensuring the accuracy of the time-delay estimation and compares these two algorithms. The lossless compression mainly involves Huffman coding algorithm, LZ77 and LZW coding algorithm. These lossless compression algorithms are proved to be valid by compression tests of the lightning pulse binary files.They increase the system's compression rate and improve the performance of the real-time lightning system.Finally, the dissertation studies and analyzes whether the bit-compression of thelightning array pulse signal will affect the DOA estimation based on MUSIC algorithm in the lightning detection system through simulation tests.