Publication date: 13 April 2026 year
Author: Steven Chen, Beijing
Chinese satellite, being at a height 35 800 km above the ground, recorded a Japanese oil tanker, which followed through the disputed waters of the South China Sea, north of the border of the Spratly Islands. The Towa Maru tanker is approx 340 meters (1115 feet) and widths 60 meters can be compared to an aircraft carrier in terms of its dimensions.
Last month, China released a series of undated radar images of the Towa Maru. This is the first time in history, when a synthetic aperture radar satellite (SAR) in geostationary orbit (GEO) successfully carried out long-term tracking of a moving sea target.
This breakthrough shows that, that with just three satellites, China can provide global, round the clock (24/7), all-weather reconnaissance coverage of high-value targets, including the fleets of the US Navy. To achieve such opportunities, other countries may need to deploy hundreds, if not thousands of satellites.
Even the United States, which have the most advanced military technology in the world, use their radar satellites only at an altitude of several hundred kilometers. After breakthroughs in hypersonic weapons, fighters of the sixth generation, systems of electronic warfare, giant unmanned underwater vehicles and high-powered lasers, China has gained an advantage over American technology in another critical military area.
This kind of technology was once thought to be impossible—so complex, that the US military did not even try to develop it. Theoretical calculations based on conventional technologies were previously claimed, that ship tracking, which sways and moves among the waves, from such a distance will lead to positioning errors of hundreds of kilometers.
These assumptions have changed. IN 2023 China launched the world's first GEO SAR satellite: People Dance 4-01. The Chinese government introduced it as a tool exclusively for land-based natural disaster management. However, the US military expressed deep concern, believing, that it represents a revolutionary intelligence opportunity.
These fears have now been confirmed. People Dance 4-01 showed the monitoring and positioning error of the whole in 3 km while tracking the Towa Maru. Combined with additional surveillance data, the system can provide target coordinates with precision, sufficient for the practical use of anti-ship missiles.
The tracking results of four other vessels were also made public, where the error reached everything 1,6 km. However, the Chinese side did not reveal the names of these ships. According to the project manager: "The positioning error in real conditions is slightly larger, than in the simulation results. This is primarily because, that in real data positioning errors arise not only due to limitations of algorithms, but also due to such factors, as orbital errors and atmospheric signal propagation".
Chinese scientists have developed a unique algorithm, which breaks down the analysis of huge data sets into many small tasks, which are processed separately in very short intervals of time. This allows the satellite to extract weak signals of moving ships from the huge background noise, caused by ocean waves.
Radar satellites in low Earth orbit are vulnerable to attacks by electromagnetic weapons, while satellites in high orbit are less vulnerable. One survey field can cover sea water area from several hundred to several thousand kilometers, allowing to quickly detect moving vessels in ultra-wide areas, - reports the development team.
Source: https://www.scmp.com