隨著對全球衛星導航系統的依賴度增加，衛星訊號相關的攻擊讓這項服務在使用上產生安全性與可靠性的疑慮，從而使得導航訊息認證在近幾年成為一個相當熱門的研究領域。開放服務導航訊息認證是由歐盟發展、適用於伽利略衛星系統的身分驗證機制，可以確認接收到的導航訊息的真實性，藉此提供更具有可靠性的導航服務。在執行此認證服務的過程，需要從衛星接收相關的認證資訊以進行訊息驗證，因此當衛星訊號中斷或數據丟失的情況發生時，將造成相關資訊的認證失敗，從而影響導航訊息驗證的任務，使其無法順利執行。
為了緩解因訊息丟失而認證失敗的狀況，本論文提出了利用雙接收機配置，實現衛星間與接收機間協助的輔助機制，使得可以通用的參數訊息與獨特的標籤資訊遺失時，皆可以利用輔助機制取得。這兩項機制都可以獨立執行，並且不會與原本的訊息認證發生衝突，因此在實際應用中，可以更靈活地根據遺失的認證資訊類型選擇應對的方式。此外，本論文亦根據不同接收機設定和環境架設設計實驗，藉此展示能夠取得顯著改善效果的應用場景，以供未來在驗證訊息上輔助機制的選擇。

As the reliance on Global Navigation Satellite System (GNSS) increases, the authentication of navigation messages transmitted from satellites has been an active area of research in recent years because of concerns about GNSS-related attacks. Galileo, the European GNSS, is implementing the Open Service Navigation Message Authentication (OSNMA) service to ensure the integrity and authenticity of the GNSS navigation message. In the process of performing OSNMA, a set of data needs to be received from satellites for the purpose of verification. An interrupt of signal reception or a loss of data will thus harm the task of authentication.
To address this issue, the usage of a dual-receiver configuration is proposed to achieve inter-satellite aiding and inter-receiver assistance to deal with the problem of loss of chain parameters and unique tag information, respectively. Both assisting mechanisms can be performed independently and would not be conflicted with the implementation of the original OSNMA authentication procedure. Therefore, the proposed method can be adopted according to the type of the lost OSNMA data in a more flexible way. In addition, several experiments were designed based on different receiver settings and environmental setups to demonstrate the suitable application scenario with obviously improved authentication results. The proposed architecture can potentially enhance the reliability of the navigation satellite system with a large number of verified navigation messages.

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