閃電之定位與誤差模擬:雷達干涉法與時間差法之分析與研究;A comparative study of lightning detection and error analysis between interferometry method and time-of-arrival technique

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Title:	閃電之定位與誤差模擬:雷達干涉法與時間差法之分析與研究;A comparative study of lightning detection and error analysis between interferometry method and time-of-arrival technique
Authors:	曾子弋;Tseng,Tzu-i
Contributors:	太空科學研究所
Keywords:	閃電;雷達干涉法;時間差法;誤差模擬;lightning;interferometry;time-of-arrival;error distribution
Date:	2014-07-24
Issue Date:	2014-10-15 14:37:36 (UTC+8)
Publisher:	國立中央大學
Abstract:	民國 101 年，中壢 52MHz 特高頻雷達站增設了一套干涉天線陣列，由 5 座八木天線排列成非等間距之十字型，提供干涉定位所需 5 路接收信號；干涉定位時必須利用不同天線間接收目標時，因傳播路徑差而產生之相位差值，推估出目標物的空間位置；本研究的主要目的是建立此干涉天線接收閃電訊號並篩選、定位之方法，並以定位結果與整合型閃電落雷偵測系統的資料進行比較。利用誤差模擬的模型，對台灣的整合型閃電落雷偵測系統，進行誤差分布的模擬，再依模擬結果，對閃電偵測系統的誤差進行分析，發現中壢、新屋附近定位誤差可能很大，閃電偵測系統本身的系統誤差也有4-5 公里。也利用誤差模擬之模型，對氣象局計劃設站的站址，進行布站位置誤差分布的模擬，並與台電的測站誤差分布進行比較利用雷達資料對閃電訊號做統計，電壓崩潰後約0.0262 秒會產生回擊；一次閃電事件，閃電通道能反射、散射雷達脈波的閃電訊號總發生時間長度為0.4624 秒；多次電壓崩潰幅射出的電磁波，總發生時間約為 0.5285 秒；雷達系統定位閃電的極限距離約為20 公里。利用雷達定位出閃電的三維結構，推測台電閃電偵測系統，在CG(cloud-ground)的判斷上有低估的現象。;The new interferometry antenna array composed with the five YAGIs is built at Chung-Li 52MHz VHF radar station in 2012. The antenna array is arranged in the form of an asymmetric cross providing that 5 channels interference received signal. The purpose of this study is to create the method of lightning positioning by interferometry antenna array. And compare the positioning result with Total Lightning Detection System. Interference positioning requires individual path differences between the receiving antennas and targets. We can estimate the spatial position of the target through phase differences due to propagation path difference. Using the simulation results of error distribution. To analyze the error of Total Lightning Detection System. By simulation result, we can find out there is a high error area near Chung-Li and Xin-Wu. It can also explain why the statistic number of data difference is large at about 11-12 KM. Also use models to simulation the error distribution for the location where central weather bureau will set lightning detection stations. And compare with Total Lightning Detection System. The stroke will happen about 0.0262 second after leader tip breakdown; The lightning signal will exist about 0.4624 second in a flash. The EM pulse radiate by electrical breakdown will exist 0.5285 second in a flash. Radar detection limit is about 20KM.Use radar data to find out Total Lightning Detection System is underestimate on CG.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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