Research And Implementation Of VHF Active Lightning Location Algorithm

At present,the commonly lightning positioning methods include active positioning and passive positioning.Active lightning location means to detect the location of lightning through radar,and passive location of lightning is a passive location based on the passive electromagnetic radiation formed by the lightning-itself.In the passive location,multi-source and multipath interference cause the error of distance measurement,and the location error multiplied.The active location of VHF(Very High Frequency)radar is based on the reflection of free electrons in the ionized atmosphere,which is based on the high temperature formed by lightning.Because of the characteristics of active detection,it overcomes the weakness of low accuracy in passive receiving,and achieves higher detection sensitivity and higher positioning accuracy.The main contributions and innovations of the paper are as follows:1.A 3 dimensional lightning location model of L array antenna was proposed.The interference equations and their positioning solutions are derived,including radial distance,pitch angle and azimuth angle.The DOA estimation of L array is carried out by multiple signal classification.Simulated and analyzed the above two methods,verified the correctness and feasibility of the two location methods.2.Through the FPGA design platform,the FPGA design of multiple signal classification method location method was completed.It mainly included 4 sub-modules work.With the aid of Modelsim simulation tools,each sub-module was simulated and verified,and the MUSIC algorithm system-simulation of the 4x4 order covariance matrix was finfished.When the signal-source number was 2,the shortest delay time of the algorithm was 53.5us.3.A set of hardware system which can verify the MUSIC positioning algorithm was designed.The hardware system included 7 parts,which were analog receiving front,A/D converters,signal processing,data caching,data transmission,flash storage,LCD display.In the hardware system,the indoor experiment operation and test result analysis of the whole MUSIC algorithm were completed.4.A location synchronization trigger detection algorithm which can detect lightning events was designed,which could monitor the occurrence of lightning in real time,output detection parameters of lightning occurrence,parameters of early warning signal and various characteristic parameters of lightning waveform.The environmental test of the location synchronization trigger module was completed in the Binzhou experiment site of Shandong province.There were 3 successful triggers,of which the first 2 times were triggered by the lightning events,and the third was the false trigger caused by the leading point discharge.By modifying the parameters of the lightning signal in the software,the false trigger about the third times were avoided.