新一代民航通訊、導航、監視與空中交通管制(Communication, Navigation, Surveillance and Air Traffic Management, CNS/ATM)的設備發展和實施，將原本的類比航空系統轉變成數位航空系統。此外，全球定位系統(Global Positioning System, GPS)在CNS/ATM系統中負責航空資訊與通訊網路之間精確時間同步校正、以及各航機的即時精確位置計算與進場降落之導航。如果GPS的受到有意或無意的干擾，將會對CNS/ATM系統的正常運行照成相當顯著的影響。因此，美國聯邦無線電導航計畫(Radionavigation Plan)和聯邦航空管理局(Federal Aviation Administration, FAA)的下一代航空運輸系統(NextGen)清楚地表明，發展一個替代的定位，導航和時間(Alternative Position, Navigation and Timing, APNT)服務系統以維持CNS/ATM運作在GPS服務中斷期間是必要的。
本研究的目的採用APNT構想中提出的廣域多點定位(Wide Area Multilateration, WAM)架構，研究及發展WAM測試平台評估其是否有能力滿足在GPS故障或中斷時維持導航服務的要求。在這篇論文研究中，使用當前在飛航所使用的廣播式自動回報監視(Automatic Dependent Surveillance-Broadcast, ADS-B)訊號以及時差定位法(Differential Time of Arrival, DTOA)用作為我們APNT的定位演算法。因此，本論文將使用軟體無線電方法(Software Defined Radio, SDR)與通用軟體無線電設備(Universal Software Radio Peripheral, USRP)發展ADS-B軟體無線電(SDR)。由於採用建立於WAM測試平台是使用DTOA演算法，故本論文需要對所有的實驗設備定義時間，以及同步ADS-B信號抵達的時間。本論文將展示ADS-B的SDR程式設計和外部硬體的配置，本論文工作將使用WAM真實數據評估DTOA方法建立WAM時間同步的能力。此外，這篇論文提出了水平精度稀釋因子(Horizontal Dilution of Precision, HDOP)，評估WAM測試平台中的ADS-B地面參考站分佈，對於台北飛航情報區APNT定位效能的影響程度。

The development and implementation of Communication, Navigation, Surveillance, and Air Traffic Management (CNS/ATM) for civil aviation have attracted a lot of attention because CNS/ATM changes the current analog aviation system to the modern digital aviation system. As the enabling technology of the modern CNS/ATM system, the Global Positioning System (GPS), for example, is utilized for time synchronization between air data network, air communication network, and aircraft navigation for approach and landing. If a GPS experiences intentional or unintentional interference, there will be a significant impact on the normal operation of the CNS/ATM. Therefore, the United States 2010 Federal Radionavigation Plan and the Federal Aviation Administration (FAA) Next Generation Air Transportation System (NextGen) clearly indicates that an Alternative Position, Navigation and Timing (APNT) system should be developed to maintain CNS/ATM operations for periods during which GPS outages occur.

The objective of this thesis is thus to research and develop a Wide Area Multilateration (WAM) evaluation test bed which is one of the APNT concepts and to evaluate whether WAM has the ability to meet the backup navigation requirements for civil aviation users during severe GPS failure and outages. In this work, the signal of opportunity under consideration is the ADS-B radio link, and the Differential Time of Arrival (DTOA) method is used as the positioning algorithm. Thus, a software defined radio (SDR) approach is used to develop ADS-B SDR on the Universal Software Radio Peripheral (USRP). Also, WAM is based on the DTOA method, and it requires defining the ADS-B signal arrival time and consideration of a time synchronization scheme for all experimental equipment. Depending on the context, this work shows the ADS-B signal structure and development of the ADS-B SDR processing and also provides a detailed discussion of the configuration of the external hardware setup used to form a WAM evaluation test bed. Finally, in order to evaluate time synchronization capability and the WAM based on DTOA method, this work shows a WAM evaluation test bed using a USRP-based ADS-B receiver with real world data. In addition, the key factor for WAM is geometric distribution of ground stations. Thus, this work presents Horizontal Dilution of Precision (HDOP) to evaluate the effect of the geometric distribution of ADS-B ground stations for WAM positioning performance in the Taipei Flight Information Region (FIR).

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