November 6, 2025
TOKYO – The Cabinet Office and the Economy, Trade and Industry Ministry are making preparations to introduce an advanced maritime digital communication system that makes use of multiple satellites in order to enhance Japan’s capabilities to detect suspicious vessels and illegal fishing boats, The Yomiuri Shimbun has learned.
Japan has lagged in developing maritime communication infrastructure compared to land-based systems. The Cabinet Office and the ministry launched two satellites this year testing if communication from the sea is feasible. They will invest ¥14.7 billion for practical implementation by fiscal 2029.
Chinese vessels repeatedly make incursions into Japan’s territorial waters. The number of maritime crimes handled by the Japan Coast Guard — including smuggling, illegal immigration and fishing as well as littering — exceeds 7,000 cases annually.
The government used to have artificial intelligence analyze satellite imagery to detect suspicious vessels. Currently, data from the Automatic Identification System (AIS) — whose installation on large vessels is mandatory — is also in use, but challenges still remain, such as location deception.
The government aims for practical use of the VHF Data Exchange System (VDES), a next-generation system of the existing AIS that enables bidirectional digital data exchange.
By operating a constellation of small satellites, the system can cover vast offshore areas beyond the reach of radio or cellular signals. Satellites relay messages, enabling text-based bidirectional communication between vessels equipped with receivers, as well as between vessels and land-based port facilities. It is believed that the new system will make location deception technically difficult.
VDES-equipped ships would provide accurate location information thereby helping quickly identify vessels that are visible in satellite imagery but go dark. Therefore, suspicious vessels can be detected highly accurately.
With about 1,800 vessel accidents occurring in Japan’s ports and elsewhere each year, sharing navigation plans via two-way communication on VDES could also help prevent such incidents.
In fiscal 2022, the government designated VDES for its Key and Advanced Technology R&D through the Cross Community Collaboration Program (K Program), which promotes public-private development of nationally important technologies, alongside next-generation battery storage technology and satellite-to-satellite optical communication technology.
Domestic companies that possess integrated satellite operation and positional data analysis technologies formed a group and currently conduct satellite-based technology demonstrations.
Sasakawa Peace Foundation Senior Research Fellow Shigeki Takaya who specializes in maritime policy said VDES can accurately deliver alerts at times of disasters or missile launches by another country and also confirm the safety of ships.
“Since Europe and other regions are moving to establish this system, Japan must actively participate in creating international rules for utilizing this new communication network,” he said.