
In February last year, four groups of high-altitude balloons were detected over northern Taiwan, home to most of the country’s population and some of its most important air defense sites. The same month, the US Air Force scrambled fighters to intercept an unmanned balloon off Kauai, a Hawaiian island that has a key missile-testing range. The PLA’s balloons have been doing much more than spy on whatever country they are flying over. According to a military official from another Asian country, one focus area in the Chinese military’s balloon flights in recent years is to collect data that can enhance the accuracy of over-the-horizon and other radar systems used for targeting in wartime. Military analysts said data points such as atmospheric density would help the PLA develop software tools known as advanced refractive effects prediction systems, which are critical for advanced radars that aid missile, air, and naval operations.