Core Viewpoint - The article discusses the navigation signal anomalies that occurred in Nanjing on December 17, 2025, clarifying the technical reasons behind the issue and emphasizing the strategic significance of the BeiDou and GPS systems' compatibility [1]. Group 1: Navigation Signal Anomaly - The core reason for the navigation failure was temporary interference suppressing GNSS satellite signals (including BeiDou and GPS), rather than a network signal interruption, making offline maps ineffective [1][3]. - Offline maps only store geographic data and cannot replace the positioning signal source, as mobile navigation relies on GNSS signals from at least four satellites to calculate location coordinates [3]. Group 2: Strategic Significance of BeiDou and GPS Compatibility - The simultaneous impact on both BeiDou and GPS signals during the anomaly validates the forward-looking strategic vision of China's BeiDou system's civilian frequency planning [1]. - The compatibility of BeiDou's civilian signal (B1C band) with GPS's civilian signal (L1C band) breaks the spectrum resource blockade and creates a strategic balance, where interference with BeiDou also affects GPS applications, enhancing security for civilian navigation services [3]. Group 3: Military Frequency Resilience - The BeiDou system employs a military-civilian frequency separation design, with military frequencies being exclusive and physically isolated from civilian bands, ensuring strong anti-jamming capabilities [3]. - The military system incorporates advanced anti-jamming technologies and algorithms, providing stable and reliable time-space services for national defense and emergency support, unaffected by the civilian signal interference [3].

Core Viewpoint - The core issue of the navigation signal anomaly in Nanjing on December 17 is attributed to temporary interference suppressing GNSS satellite signals, including BeiDou and GPS, rather than a network signal interruption [1] Group 1: Technical Analysis - The offline maps are ineffective in resolving the navigation anomaly, as the core problem lies in the GNSS satellite signal interference [1] - Both BeiDou and GPS signals were simultaneously affected, highlighting the strategic foresight in the planning of China's BeiDou system for civilian frequency bands [1] Group 2: Impact on Military and Civilian Use - The signal anomaly only impacted civilian GNSS frequency bands, while the military frequency of BeiDou remained completely unaffected [1]