Attitude Determination and Control (ADC) actively ensures a spacecraft maintains and adjusts its orientation in space. Satellites perform diverse tasks, including Earth observation, weather monitoring, telecommunications, and scientific research. Even slight orientation errors can miss critical data collection windows or disrupt communication with ground stations. Commonly used sensors in ADC include gyroscopes for measuring rotation rates, sun sensors for solar alignment, and magnetometers for detecting Earth’s magnetic field. For high-precision tasks, such as deep space probes or high-resolution imaging satellites, star trackers excel as the top choice.
A star tracker, an optical sensor, captures star field images to determine a spacecraft’s orientation. Designed for harsh space environments—extreme temperatures, radiation, and vacuum—star trackers transform the universe’s constant background into a reliable map. They provide absolute attitude reference unmatched by other sensors.
Star trackers deliver unparalleled precision in measuring a spacecraft’s orientation. They lock onto fixed stars, providing absolute reference points independent of the satellite’s position or motion. In autonomous missions, like Mars explorations, star trackers enable “lost in space” recovery. If a satellite loses orientation due to power failures or solar flares, the tracker independently reacquires attitude by scanning the sky and matching stars to a database.
Image Acquisition: The tracker captures digital images of star fields through its optical lens.
Star Detection and Centroid Calculation: Advanced image processing identifies bright spots (stars) and calculates their centroids with sub-pixel precision.
Pattern Matching: Observed star patterns match an onboard catalog containing thousands of stars’ positions, brightness, and spectral data.
Attitude Calculation: After identifying stars, the tracker computes quaternions or Euler angles representing the satellite’s orientation, outputting data to the ADC system.
Error Correction and Autonomy: Built-in software handles anomalies, like bright objects (e.g., planets) entering the field of view, by filtering them or switching to backup modes.
Size and Cost: High-end models can be bulky and expensive, though miniaturization addresses small satellite needs.
Sensitivity to Interference: Bright light from the sun, moon, or Earth may blind the sensor, requiring baffles or operational windows.
Computational Demands: Processing star catalogs needs onboard computing power, though AI advancements optimize this.
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TY-Space Technology (Beijing) Ltd. is professional focusing on advanced attitude optical sensors, especially Star Trackers for space industry.
