Unveiling the "Land Exploration 1 A Star" space autonomous driving: "space-time revisit" to predict geological disasters

On January 26, China successfully launched a land exploration 1 Group A satellite with the Long March 4 C carrier rocket. The picture shows the satellite development data map.　Photo by Zhang Yang

China News Network Haihai January 26 Title: Unveiling the "Lu Tan No. 1 A Star" Space Autonomous Driving: "Time and Space Revisit" to predict geological disasters

Author Zheng Yingying Ma Shuaisha Chen Baojuan

On January 26, Beijing time, China successfully launched the "Land Exploration No. 1 Group 01 A Star" (abbreviation: Lu Tan No. 1 A Star), which is equipped with China's first high-precision surface micro-deformation monitoring radar system based on space observation, which is an extremely picky "passenger", for this reason, the development team of the Attitude Orbit Control Subsystem of the Eighth Academy of China Aerospace Science and Technology Corporation gave the satellite excellent "driving" technology.

"Revisiting time and space": the premise of geological disaster prediction

Wang Wenyan, deputy chief designer of the "Land Exploration No. 1 Group 01 A Satellite", made an analogy: "The attitude orbit control subsystem is the satellite's driving system, and its design depends entirely on the individual needs of the 'passengers', and some 'passengers' need to take long-range images of a certain part of the earth, which requires the attitude orbit control subsystem to be accurate and stable enough; some 'passengers' like to take close-ups, which requires the attitude orbit control subsystem to be flexible enough and never lose." For the Land Exploration No. 1 Group 01 A star, the biggest requirement of the 'passengers' is to be able to conduct a high-precision 'space-time revisit' of the target point of the shooting. ”

"The satellite is constantly orbiting in the Earth's orbit, and the so-called high-precision 'space-time revisit' means that the satellite can return strictly to the sky above the initial target point after a regression cycle." Wang Wenyan said. She further explained that the strictness here includes the dual constraints of time and space, which is an important premise for the "Land Exploration No. 1 Group 01 A Star" to complete the monitoring of surface deformation and thus support the prediction of geological disasters.

"Space Lane": An accuracy span from kilometers to 100 meters

For conventional neo-Earth satellites, the orbital control accuracy is usually between a few kilometers and tens of kilometers, while the control accuracy of the "Land Exploration I Group 01 A Satellite" is increased from the kilometer level to the hundred meter level, and the constraints are upgraded from one dimension to three dimensions.

Satellites flying in space, in fact, there is a "lane", affected by various factors, "land exploration no. 01 group A star" flight trajectory will change up and down, left and right, the formation of "lane" like a three-dimensional "pipe".

In order to ensure that the satellites should run in the prescribed "pipeline" as much as possible during flight without yawing, the attitude orbit control subsystem team of the Eighth Academy of China Aerospace Science and Technology Corporation has created an "automatic driving system" with high-precision pipeline navigation and control as the core, so that the "Land Exploration No. 1 01 Group A Star" can drive autonomously and stably.

"We stretch a three-dimensional space with the target reference orbit as the central axis and the orbital control accuracy requirements as the radius, which is shaped like a pipe, and we want to firmly control the satellite in this pipeline space." Du Yaoke, chief designer of the satellite's attitude orbit control subsystem, said. He said that pipeline navigation technology can accurately calculate the time and space deviation of the satellite's "yaw", and then drive the "steering wheel" (referring to: pipeline control) to ensure that the satellite is always running in the predetermined space.

According to reports, when repeated observations, the satellite orbit pipeline control radius of the land exploration No. 1 group A satellite can be accurately controlled within 350 meters, reaching the international advanced level.

"Autopilot": Set the navigation route without yawning

The research and development team innovatively proposed an orbit control scheme based on the "virtual formation flight theory", that is, to treat the target reference orbit as a "hypothetical host star", let the land exploration No. 1 01 group A star follow autonomously, give the satellite "automatic driving" ability, and "carefully" formulate a control strategy to minimize the consumption of spaceborne propellant. According to reports, such a practice is also an important development trend in the field of long-life application satellites in the future.

Du Yaoke, the chief designer, said that in order to meet the needs of the mission, the satellite was pre-installed with a target reference orbit that returned to the accuracy of the meter level, that is, the "navigation route", to guide the satellite to arrive at the predetermined location on time and accurately. The task of the attitude orbit control subsystem is to ensure that the satellite can always drive strictly in accordance with the "navigation route" and not yaw under the real and complex space environment. (End)