TOKYO -- Japan will overhaul its missile intercept command system starting in fiscal 2018 to cope with advancements in North Korea's weapons technology, such as faster-descending missiles launched at a steeper trajectory.
The Japan Aerospace Defense Ground Environment, or JADGE, detects incoming missiles via radar and combines that information with data from American military satellites and other sources to determine the rockets' trajectory and likely point of impact. If the missiles are expected to strike Japan, land- and ship-based interceptors are ordered to shoot them down.
But many believe the current system could have trouble dealing with high-powered missiles launched at a lofted trajectory, a method that sacrifices range for height and a speedy descent. The intercontinental ballistic missile that North Korea launched last Wednesday took such a path. Rapidly calculating a high-flying missile's speed and direction and determining whether it was launched by friend or foe requires a great deal of computing power, and "it is possible the current system would not be able to keep up" to intercept such a rocket, an official from the Ministry of Defense said.
JADGE will receive the additional power needed to make these judgments in an upgrade starting next fiscal year. The defense ministry is requesting 10.7 billion yen ($94.8 million) in the fiscal 2018 budget to make the changes, and hopes to fully deploy the upgraded version in fiscal 2022.
By more quickly issuing the command to intercept, the system will have an easier time neutralizing missiles on a lofted path. The upgraded JADGE will also be better able to pick out multiple missiles at once, enabling it to respond to situations such as when North Korea fired four intermediate-range rockets simultaneously in March. In addition, the system will be able to more accurately intercept projectiles that provide few warning signs before a launch, such as submarine-launched ballistic missiles and rockets using solid-fuel engines.
Japan is building up other aspects of its missile defense as well. It is jointly developing with the U.S. the next-generation SM-3 Block IIA Interceptor missile, targeting deployment on Japan's Aegis destroyers starting in fiscal 2021. The interceptors will have a range of more than 1,000km, compared to several hundred for current-generation SM-3s.
The Self-Defense Forces will also have 28 units operating Patriot Advanced Capability-3, or PAC-3, surface-to-air interceptors by fiscal 2020, up from 17 units currently. These systems will be steadily replaced with upgraded versions featuring twice the range.
Japan is also carefully analyzing North Korea's nuclear and missile technology to determine the risks presented. Some U.S. experts believe the ICBM launched last week broke up while re-entering the Earth's atmosphere, as the projectile was confirmed by Japanese radar to have split into multiple pieces before falling into the Sea of Japan. "If the ICBM did in fact fail at re-entry, it can hardly be called complete," according to a Japanese government source.
Tokyo has released no official opinion as to whether the missile successfully re-entered the atmosphere. "It is possible the warhead section of the missile was intentionally separated from the rest using a booster rocket to more accurately guide the projectile," a national security source said.