On December 19, the "Nanjing Satellite Association" WeChat public account released "Technical Discussion and Analysis of Abnormal Situations in Nanjing Regional Navigation Signals on December 17." which mentioned,The core reason for this navigation failure was that GNSS satellite signals (including Beidou and GPS) were temporarily interfered with and suppressed, rather than network signal interruption.Therefore, downloading offline maps has no practical significance.This interference accurately targeted Beidou and GPS civilian frequency bands.As a result, the positioning signal cannot be recognized by the receiver. Even if it is equipped with an offline map, problems such as positioning drift and no data feedback will occur due to the lack of location data sources, making it impossible to achieve effective navigation. The full text is as follows:
All member units and all sectors of society:
On the evening of December 17, 2025, navigation and positioning anomalies occurred in some areas of Nanjing, which aroused widespread social concern.
In order to clarify public misunderstandings and interpret technical principles and strategic value, Nanjing Satellite Application Industry Association makes the following explanation:
1. Offline maps cannot solve this navigation abnormality problem
The core reason for this navigation failure was that the GNSS satellite signals (including Beidou and GPS) were temporarily interfered with and suppressed, rather than the network signal being interrupted, so downloading offline maps was of no practical significance.
From a technical perspective:
1. The core function of offline maps is to store geographical data, which only solves the "map display" problem and cannot replace the source of positioning signals;
2. Mobile phone navigation needs to rely on GNSS satellite signals (at least 4 satellites) to resolve position coordinates, and then match the position information to the map. Positioning signals and map data are two independent systems;
3. This interference is precisely targeted at the Beidou and GPS civil frequency bands, causing the positioning signal to be unable to be recognized by the receiver. Even if it is equipped with an offline map, there are problems such as positioning drift and no data feedback due to the lack of position data sources, making it impossible to achieve effective navigation. (Offline maps are more suitable for areas with satellite positioning signals and no communication network signals, such as high seas, deserts and deep mountains).
2. The strategic significance of Beidou and GPS civilian frequency band compatibility has been verified
The simultaneous impact of Beidou and GPS signals in this anomaly confirms the forward-looking strategic vision of my country's Beidou system civil frequency band planning:
1. International satellite navigation spectrum resources follow the "first come, first served" rule. GPS occupied the core resources of the L-band in the early years. When the Beidou project was established, there was little high-quality spectrum left;
2. Based on the ITU framework, Beidou civil signals (B1C frequency band) and GPS civil signals (L1C frequency band) are compatible and interoperable, which not only breaks through the spectrum resource blockade,It has also formed a strategic balance of "interfering with Beidou means interfering with GPS";
3. Taking into account the military binding characteristics of the United States and the European Union, the NATO system also relies on the GPS signal frequency band. This frequency band compatible design builds an important strategic deterrent - any interference against Beidou civilian signals will simultaneously affect GPS-related applications, fundamentally curbing the possibility of malicious interference and building a security barrier for my country's civil navigation services.
3. Beidou military frequencies have strong anti-interference capabilities and will not be affected
It should be clearly stated that this signal anomaly only involves the civilian GNSS frequency band, and Beidou military frequencies are completely uninterrupted:
1. The Beidou system adopts a separation design for military and civilian frequency bands. Military frequencies are exclusive confidential frequency bands and are physically isolated from civilian frequency bands;
2. Military systems are equipped with core technologies such as fully digital anti-interference technology and adaptive intelligent filtering algorithms, which can accurately identify and filter interference signals, and have strong anti-interference and anti-deception capabilities;
3. As an important national space infrastructure, the independence and anti-interference properties of Beidou military frequency bands have always provided stable and reliable space-time services for national defense security and emergency support in key areas. This core capability has never been affected by this civilian signal interference.
If this navigation anomaly is a temporary signal control measure required for the security of a major event, it is also a conventional security measure in the industry. The relevant signals have gradually returned to normal after the event.
The Nanjing Satellite Application Industry Association will continue to pay attention to industry trends, share satellite application expertise in a timely manner, and help the public scientifically understand satellite navigation technology.
The Southern Health Association will continue to build a communication bridge between enterprises and the government under the leadership of the Chinese Health Association. Relevant enterprises are welcome to actively participate in the conference, and the association will waive membership fees.
Nanjing Satellite Application Industry Association
December 18, 2025
According to Jiangsu News, on the evening of December 17, some netizens in Nanjing reported that many commonly used navigation software systems suddenly experienced abnormalities. The navigation interface continues to display "Driving on a road without data". Delivery riders have also reported problems with built-in navigation such as delivery software. "Invisible navigation" may lead to delays in takeout delivery. Coincidentally, some shared bicycles also have positioning errors. A Nanjing netizen said that he used a shared bicycle for just five or six minutes, but when he parked it, it "showed that it was outside the operating range" and "could not turn off the lock." After the forced lockdown, the end point of the order was located 57 kilometers away.