Core Viewpoint - On December 17, 2025, a navigation signal anomaly occurred in Nanjing, affecting multiple navigation software systems and causing delivery delays for food delivery services due to the inability to access navigation data [12][18]. Group 1: Technical Analysis of the Navigation Anomaly - The core reason for the navigation failure was temporary interference suppression of GNSS satellite signals (including Beidou and GPS), rather than a network signal interruption, making offline maps ineffective [6][20]. - Offline maps only store geographic data and cannot replace the positioning signal source, as mobile navigation relies on GNSS satellite signals to calculate location coordinates [8][21]. - The interference specifically targeted the civilian frequency bands of Beidou and GPS, leading to the inability of receivers to recognize positioning signals, resulting in navigation drift and lack of data feedback [8][22]. Group 2: Strategic Significance of Beidou and GPS Compatibility - The simultaneous impact on Beidou and GPS signals during the anomaly validates the forward-looking strategic vision of China's Beidou system's civilian frequency band planning [8][22]. - The international satellite navigation spectrum resources follow a "first come, first served" rule, with GPS having occupied core L-band resources early on, leaving limited quality spectrum for Beidou [8][22]. - The compatibility of Beidou's civilian signal (B1C band) with GPS's civilian signal (L1C band) not only breaks the spectrum resource blockade but also creates a strategic balance where interference with Beidou also affects GPS applications [8][22]. Group 3: Resilience of Beidou Military Frequency - It is important to note that the signal anomaly only affected civilian GNSS frequency bands, while Beidou's military frequencies remained completely unaffected [9][23]. - The Beidou system employs a military-civilian frequency separation design, with military frequencies being exclusive and physically isolated from civilian bands [9][23]. - The military system is equipped with advanced anti-jamming technology and adaptive filtering algorithms, providing strong resistance to interference and deception, ensuring stable and reliable time-space services for national defense and emergency support [9][23].