Nanjing's navigation failure revealed, suppressed by mysterious signals, while Beidou military signals remain unaffected! It is likely that the West will be disappointed.
On December 17, many citizens of Nanjing found that when using their mobile phones or car navigation systems, there was sudden positioning drift and route errors, even direct "disconnection" — the map software displayed "unable to obtain current location." At once, "Is it a network problem?" and "Should we download offline maps in advance?" became hot topics of discussion.
On December 19, the Nanjing Satellite Application Industry Association released a technical analysis, revealing the real reason behind this anomaly: it was not a network failure nor a map software crash, but rather interference with the GNSS global navigation satellite system signals.
This time, both Beidou and GPS were affected. Although these two systems are developed by different countries, they both use the internationally common L-band frequency for civilian services. This means that if this frequency band is suppressed, whether you use the domestic Beidou or the American GPS, they would all "go blind" collectively.
Where did the interference come from? The association did not specify the exact source, but clearly stated that it was a "temporary suppression," which is very likely to come from an illegal ground-based transmitting device. Although such devices have small power, if they happen to operate near the GNSS civilian frequency band, they may cause signal drowning in local areas. This situation is not uncommon worldwide, for example, signal shielding devices are often set up around airports and military restricted areas; however, it is indeed worth being vigilant when it occurs in the city center.
There is another key detail in this incident that has been widely overlooked: the Beidou military signals remained completely unaffected. When designing the Beidou system, our country strictly separated the military and civilian frequency bands, and equipped the military signals with stronger anti-interference capabilities, such as more complex modulation methods, higher transmission power, and dedicated encrypted channels.
Therefore, even if the civilian frequency band is suppressed, systems relying on high-precision military services of Beidou, such as the military, emergency command, and critical infrastructure, can still operate stably. It is unknown whether the anti-interference capability of the Beidou military version might disappoint some people in the West.
Original article: toutiao.com/article/1851995332465675/
Statement: This article represents the personal views of the author.