The Design And Test Of Antenna-feeder And Receiving Front-end Of Cloud-to-Ground Lightning Detection Station

Lightning detection refers to use the electromagnetic properties of lightning radiationto monitor the Cloud-to-Ground(CG) lightning discharge parameters(time, location,intensity, polarity, energy etc), which plays an important role in the field of lightningprotection，monitoring and early warning. The design of antenna-feeder and receivingfront-end are the main work in this article.First, it summarizes the overall structure of the lightning detection stations, whichmainly include time-frequency unit, the unit of receiving-sampling-processing forCloud-to-Ground, the unit of receiver for Cloud-to-Ground and the unit of signal generatorfor Cloud-to-Ground, and describes the main function of each unit for CG lightning. Thissystem adopts the lateral technology of Magnetic Direction Finder and the correctionmethod of amplitude comparison in dual receiver, and gives the composition principle ofthe three-channel receiver system.Secondly, according to the needs of the project, it analyzes the radiation mechanismand the electrical performance parameters of short electric dipole and magnetic dipole,sets the parameters of antenna-feeder and outdoor receiver-front on this basis, and putsforward the design scheme of the antenna-feed system. This scheme is composed oforthogonal loop antennas and electric field antenna. Then the design principle and theblock diagram of outdoor receiving front-end are given, including the signal’s lightningsurge, low-pass filter, impedance transformation and other functions. And simulate thedesign principle of the receiving front-end, the results show that the obtained parametersmeet the requirements of the design.Thirdly, the unit module of indoor receiving front-end mainly includes lightning surgeprotection circuit, low pass filter circuit, variable gain circuit, active filter and amplifiercircuit and ADC analogue-digital conversion circuit. In regard to the ADC acquisition unit,each channel’s performance index is tested, which show that the design parameters arefully meet the design requirements.Finally, it mainly introduces the hardware design and software implementation of thepulse signal source of simulated CG lightning. This unit is mainly used to produce signals which are needed for the project, in regard to the signal’s generation， the principle ofdirect digital synthesis technology is summarized. Based on the signal’s randomcharacteristics, several methods of random signal generator are putted forward, and therandom sequence generating principle and realization method are given.