Why do Japanese mobile phones receive alerts when North Korea launches missiles?

We all know that in terms of military early warning, Japan has worked with the United States to build an advanced early warning detection system, which mainly includes the early warning radar of the Ground Self-Defense Force and the early warning radar on the Maritime Self-Defense Force Aegis ship. Detection systems, the AN/TPY-2 mobile radar and missile early warning satellites deployed by the United States around Japan, can basically detect North Korean missile launches accurately. In terms of civilian use, alarm systems such as Japan's J-ALERT cannot be underestimated.

The "National Instant Alert System" (J-ALERT) of Japan's Ministry of Internal Affairs and Communications Fire Department was put into use in February 2007, aiming to quickly convey emergency information to the general public in critical moments. At present, the coverage rate in various regions in Japan has reached 100%. The system processes information based on artificial satellites. When a natural disaster or emergency occurs, it automatically issues warnings through ground systems and the Superbird-B2 communication satellite in space. The scope of the alert includes “national protection alerts” for earthquakes, tsunamis, volcanic eruptions, severe weather information, missile threats, air strikes, large-scale terrorism, etc.

Many years ago, the Japanese government mandated that mobile phones sold in the country must have built-in disaster emergency response functions. In this way, the emergency alarm of the J-ALERT system can bypass the volume and notification management of the mobile phone system, and directly issue alarm sounds and text reminders when there is no network data connection. In addition, many third-party applications on mobile phones can also issue instant alerts.

Therefore, as long as a missile launched by North Korea flies towards Japan, the military's missile warning information can be quickly released to relevant areas in Japan, and residents' mobile phones will receive real-time alerts. This information-based emergency alert mode for emergencies is also a direct reflection of the island nation’s crisis awareness.