Core Viewpoint - The Nanjing Satellite Application Industry Association released a technical analysis regarding the navigation signal anomalies that occurred in Nanjing on December 17, 2025, clarifying misconceptions and explaining the technical principles and strategic significance of the incident [3][4]. Group 1: Navigation Signal Anomaly - On the evening of December 17, 2025, navigation positioning anomalies were reported in certain areas of Nanjing, raising widespread public concern [3]. - The core reason for the navigation failure was identified as temporary interference suppressing GNSS satellite signals (including Beidou and GPS), rather than a network signal interruption [4][5]. - Offline maps cannot resolve the navigation anomaly issue, as they only store geographic data and do not replace the positioning signal source [5]. Group 2: Technical Principles - Mobile navigation relies on GNSS satellite signals (at least four satellites) to calculate position coordinates, and positioning signals and map data are independent systems [5]. - The interference specifically targeted the civilian frequency bands of Beidou and GPS, preventing the positioning signals from being recognized by receivers, leading to issues such as position drift and lack of data feedback [5]. - Offline maps are more suitable for areas with satellite positioning signals but without communication network signals, such as open seas or remote mountains [5]. Group 3: Strategic Significance of Beidou and GPS Compatibility - The simultaneous impact on both Beidou and GPS signals during the anomaly validates the strategic foresight of China's Beidou system's civilian frequency planning [6]. - The international satellite navigation frequency spectrum follows a "first come, first served" rule, with GPS having occupied core L-band resources early on, leaving limited quality spectrum for Beidou [7]. - 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 [7]. Group 4: Military Frequency Resilience - The signal anomaly only affected civilian GNSS frequency bands, while Beidou's military frequency remained unaffected [8]. - Beidou employs a military-civilian frequency separation design, with military frequencies being exclusive and confidential, physically isolated from civilian bands [8]. - The military system incorporates advanced anti-jamming technologies, ensuring strong resilience against interference and deception, providing stable and reliable time-space services for national defense and emergency response [8]. Group 5: Ongoing Industry Engagement - If the navigation anomaly was a result of temporary signal control measures for major event security, it is considered a routine safety measure within the industry [8]. - The Nanjing Satellite Application Industry Association will continue to monitor industry dynamics and share professional knowledge on satellite applications to enhance public understanding of satellite navigation technology [8]. - The association aims to build a communication bridge between enterprises and the government, encouraging relevant companies to participate in meetings without membership fees [8].