China has made significant advancements in satellite-to-ground laser communication, potentially setting the stage for 6G technology and enhancing applications such as ultra-high-resolution remote sensing and next-generation satellite positioning systems.
Chang Guang Satellite Technology Co., the operator of Jilin-1, which boasts the largest sub-meter commercial remote sensing satellite constellation globally, announced that it achieved an impressive transmission rate of 100 gigabits per second for ultra-high-speed image data during tests conducted last weekend.
This achievement, which is ten times faster than their previous record, was realized through a connection between a truck-mounted ground station and one of the 117 satellites in the Jilin-1 constellation, as reported by the company.
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Wang Hanghang, the head of laser communication ground station technology at the company, stated that this development positions Chang Guang Satellite ahead of Elon Musk's Starlink.
"Musk's Starlink has revealed its laser inter-satellite communication system but hasn't deployed laser satellite-to-ground communication yet. We think they might have the technology, but we've already started large-scale deployment," he said.
"We plan to deploy these laser communication units across all satellites in the Jilin-1 constellation to improve their efficiency, with a goal of networking 300 satellites by 2027."
Wang stated that this advancement "establishes the groundwork for the effective deployment and operation of China's satellite infrastructure, which encompasses navigation, 6G internet, and remote sensing applications."
He noted that while the expenses associated with upgrading ground stations are significant, satellite communication provides a cost-effective solution with extensive coverage, positioning it as an "essential avenue" for 6G development. "Laser communication will also be a crucial technology in the future."
As satellites achieve greater spatial and temporal resolutions, the amount of data they produce is increasing rapidly, leading to a bottleneck in traditional microwave data transmission bandwidth.
Acknowledging this impending challenge, Chang Guang redirected its efforts towards laser communications technology in early 2020, a sector that has made considerable progress in recent years.
In 2022, the Massachusetts Institute of Technology (MIT) reached a significant milestone with a 100Gbps laser transmission, followed by NASA's TeraByte InfraRed Delivery (TBIRD) system—also developed by MIT—which set a new record of 200Gbps in 2023.
The TBIRD payload is compact, consisting of three 10cm (4in) cubes that together are roughly the size of a tissue box, while its receiving station is located at NASA's Jet Propulsion Laboratory in California.
In contrast, China's larger and heavier system has a payload weight of approximately 20kg (44lb), and its ground receiving unit is truck-based, providing mobility that could facilitate quicker applications.
The laser communication terminal developed by Chang Guang, comparable in size to a backpack and capable of supporting both inter-satellite and space-to-Earth data transmission, was part of the payload of a satellite launched in June 2023.
The Jilin-1 02A02 satellite, chosen for this trial, was part of a record-setting mission that successfully deployed 41 satellites into orbit with a single rocket, enhancing the Chinese satellite constellation.
The mobile configuration of the vehicle-mounted laser communication station allows it to circumvent atmospheric interferences, such as severe weather and turbulence, thereby improving the reliability and stability of data transmission from space to Earth.
"We plan to establish multiple receiving stations across China to improve the efficiency of remote sensing image data acquisition," Wang said.
The system previously set a record with a 10Gbps space-to-Earth data transfer in October 2023. By January of the previous year, the company had successfully executed China's inaugural 100Gbps inter-satellite transmission between the 02A01 and 02A02 platforms.
The team navigated various technical hurdles to reach this latest milestone, including challenges related to atmospheric turbulence, high-speed relative motion inaccuracies, and precise beam tracking.
Achieving a 100Gbps transmission rate from a satellite to Earth "is akin to sending 10 full-length movies in just one second. It's comparable to transforming a single-lane highway into thousands of lanes," Wang remarked.
As per the company's official report, the potential applications are vast, covering areas such as disaster monitoring, national defense, smart cities, environmental protection, and emergency response, in addition to 6G satellite internet.
This latest accomplishment represents a major advancement for China's satellite communication capabilities, reinforcing its standing in the global space technology competition.