<title>Star tracker for remote sensing satellites</title>

The high resolution satellite with the longer focal length and the larger aperture has been widely used in georeferencing of the observed scene in recent years. The consistent end to end model of high resolution remote sensing satellite geometric chain is presented, which consists of the scene, the three line array camera, the platform including attitude and position information, the time system and the processing algorithm. The integrated design of the camera and the star tracker is considered and the simulation method of the geolocation accuracy is put forward by introduce the new index of the angle between the camera and the star tracker. The model is validated by the geolocation accuracy simulation according to the test method of the ZY-3 satellite imagery rigorously. The simulation results show that the geolocation accuracy is within 25m, which is highly consistent with the test results. The geolocation accuracy can be improved about 7&thinsp;m by the integrated design. The model combined with the simulation method is applicable to the geolocation accuracy estimate before the satellite launching.

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Observation satellite attitude estimation using sensor measurement and image registration fusion

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410017691315 ◽

2017 ◽

Vol 232 (7) ◽

pp. 1390-1402 ◽

Cited By ~ 4

Author(s):

Zhao-Xiang Zhang ◽

Guo-Dong Xu ◽

Jia-Ning Song

Keyword(s):

Remote Sensing ◽

Image Registration ◽

Attitude Determination ◽

Simulated Data ◽

Star Tracker ◽

Remote Sensing Images ◽

Bias Drift ◽

Satellite Attitude ◽

Simulation And Experiment ◽

And Control

In order to enhance the accuracy and the robustness of the attitude determination and control system in observation satellites, a new way to fuse gyro and star tracker measurement with image registration is described. In this method, a novel and complete framework is proposed to estimate the on-orbit attitude variations from multi-spectrum remote sensing images. An extended Kalman filter is derived to calibrate the gyro bias drift and the star tracker error. The new framework is tested with realistically simulated data and remote sensing images based on JL-1 satellite. Simulation and experiment results indicate that based on the image registration, the satellite attitude variations could be detected in real time and applied for the accurate gyro and star tracker bias calibration.

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A Compressed and High-Accuracy Star Tracker with On-Orbit Deployable Baffle for Remote Sensing CubeSats

Remote Sensing ◽

10.3390/rs13132503 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2503

Author(s):

Xinyuan Liu ◽

Fei Xing ◽

Shaoyan Fan ◽

Zheng You

Keyword(s):

Remote Sensing ◽

Dynamic Performance ◽

High Accuracy ◽

Stray Light ◽

Star Tracker ◽

Measuring Instruments ◽

Sensing Applications ◽

Size Limitation ◽

Circuit Structure ◽

Pointing Accuracy

CubeSats have been widely used in remote sensing applications such as global coverage, hotspots revisited, etc. However, due to the strict size limitation, the high-accuracy measuring instruments such as star tracker are too large to be applied in CubeSat, thus causing insufficient accuracy in satellite attitude and image positioning. In order to reduce the volume of star tracker without compromising the performance, the relationship between the volume and pointing accuracy or dynamic performance is studied and an optimization model of star tracker with a minimum volume is proposed. Compared with the traditional star tracker, a deployable star tracker with a novel deployable baffle and surrounded circuit structure is designed. The baffle consists of nested three-stage sub-baffles with a scientifically analyzed and verified taper to achieve smooth deployment and compression. The special circuit structure surrounds the lens and can be compressed in the inner sub-baffle. Therefore, the deployable star tracker can be compressed to the smallest volume and the sub-baffles can be deployed to the accurate position without self-lock risk. The experimental results verify its deployment accuracy and reliability as well as space environmental adaptability. The deployable star tracker has almost the same results on stray light suppression ability, pointing accuracy (better than 3″ (3σ)) and dynamic performance (up to 3°/s) with the traditional star tracker. Furthermore, an integrated attitude determination and control system based on the deployable star tracker for CubeSat is further designed and implemented to support high-accuracy remote sensing.

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