![\"Schematic](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/03\/schematic-diagram-of-ground-station-site-selection-based-on-system-availability-1200x803.jpg\")
An SGLC system containing one GEO satellite and four candidate ground stations with a scheduling period of one time slot. Credit: Lyu, P., Zhao, K., & Zhao, H. (2025)<\/p>\nAt Lijiang Observatory in southwestern China, a laser signal descended from a satellite parked 36,000 kilometers above Earth. It did not arrive as a clean, steady beam. The atmosphere had already begun scattering and deforming the light long before it reached the ground. What researchers recovered from that distorted signal was a 1Gbps data downlink transmitted with only 2 watts of power.<\/p>\n
The transmission rate was roughly five times faster than speeds typically cited for SpaceX\u2019s Starlink service, though the two systems are built for different purposes. Starlink operates from low Earth orbit, a few hundred kilometers up, using radio antennas to serve individual homes. The Chinese test came from a geostationary orbit more than 60 times higher and relied on a specialized ground station with a 1.8-meter telescope.<\/p>\n
An SGLC system containing one GEO satellite and four candidate ground stations with a scheduling period of one time slot. Credit: Lyu, P., Zhao, K., & Zhao, H. (2025)<\/p>\n
What made the demonstration possible was a ground system designed not to fight the atmosphere, but to work with the wreckage it creates. As a laser beam<\/a> passes through shifting layers of air, the light scatters. What begins as a focused signal becomes a weak, fuzzy patch spread across hundreds of meters by the time it touches the ground.<\/p>\n A Receiver That Sorts the Damage<\/p>\n Earlier methods tried to solve atmospheric distortion in two ways. Adaptive optics sharpens the distorted wavefront with movable mirrors. Mode diversity reception collects scattered fragments of the signal and tries to reassemble them. Neither approach worked well on its own when turbulence was strong.<\/p>\n The research team, led by Wu Jian of Peking University of Posts and Telecommunications and Liu Chao of the Chinese Academy of Sciences, combined the two strategies. Their ground system at Lijiang used a correction stage with 357 micro-mirrors that adjusted in real time to clean up the incoming light. The signal then moved through a multi-plane light converter, which split it into eight separate channels. A processor identified the three strongest channels and combined only those for decoding.<\/p>\n This approach accepted that the atmosphere would damage the beam. Rather than attempting to restore the signal to perfect form, the system simply found the parts that survived and stitched them together. The proportion of usable signal rose from 72 percent to 91.1 percent, according to the results published in the Chinese journal Acta Optica Sinica<\/a>.<\/p>\n A Different Kind of Comparison<\/p>\n The contrast with Starlink drew attention, but the two systems are not direct competitors. Starlink satellites orbit at roughly 550 kilometers and communicate with consumer terminals using radio frequencies. Their job is to serve millions of users simultaneously across a moving constellation.<\/p>\n The Chinese test, by comparison, was a point-to-point demonstration from a fixed orbital position. The 2-watt laser transmitter draws about as much power as a small LED bulb. From a distance of 36,000 kilometers, delivering a gigabit-per-second link with that little power represents a meaningful engineering benchmark.<\/p>\n One trade-off is the ground equipment. The Lijiang setup is not a home broadband terminal. It is a specialized receiver built around a large telescope and a roomful of signal processing hardware. That kind of infrastructure fits best in a backbone role, where a handful of ground stations collect high-volume data from orbit and feed it into terrestrial fiber networks.<\/p>\n A Signal Pulled From the Sky Above Yunnan<\/p>\n The most punishing part of the journey happened directly above the observatory. That is where the beam lost its shape, where the light scattered, and where the downlink risked becoming noise. The receiving system did more than endure that interference. It pulled a coherent data stream from a signal that had already been scrambled by the sky.<\/p>\n In practical terms, the reported speed translates to sending a high-definition movie from Shanghai to Los Angeles in under five seconds. Whether that figure holds under varying weather conditions or different atmospheric states remains an open question. The test represents a single successful demonstration, not an operational service.<\/p>\n The Lijiang Observatory sits in Yunnan province, a region where high-altitude mountain sites offer clearer atmospheric conditions for optical astronomy and communications testing. The location itself points to a strategic interest in ground stations that can operate with modest power requirements and limited infrastructure footprint.<\/p>\n![\"Geostationary](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/03\/geostationary-satellites-orbit-the-earth-at-36-000-km-while-the-emerging-breed-of-low-and-medium-ear.png\")
Geostationary satellites orbit the earth at 36 000 km while the emerging breed of low and medium earth orbiting satellites (LEOs and MEOs) orbit the Earth at heights ranging from 500 km to 10 500 km. Credit: Don Clarke<\/p>\n![\"Adaptive](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/03\/adaptive-deformable-mirror-sampl.jpg\")
Components of an adaptive secondary mirror for a telescope, which uses actuators to control a thin mirror\u2019s shape.\u00a0Credit: Microgate<\/p>\n