Satellite Vibration Characterization via Star Trail Analysis
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Solution Overview
Problem
Current methods for evaluating image quality degradation due to high-frequency vibrations in earth surface observation satellites are costly and time-consuming, as they require extensive image acquisition and complex processing of images from terrestrial sites that are often obscured by cloud cover.
Innovation Solution
A method involving selecting a star, extracting its coordinates, orienting the satellite to scan a window around the star, acquiring an image with a trail corresponding to the star, and analyzing the image to determine vibration characteristics, allowing for optimization of image quality by adjusting the speed of gyroscopic actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If methods using extensive image acquisition and complex processing of terrestrial sites are used to evaluate image quality, then measurement precision is improved, but loss of time and device complexity increase
Solution Approach 1:
The invention extracts the essential vibration information by observing a single star instead of processing multiple terrestrial sites. The star's known position serves as a reference point, and its image trail directly reveals vibration characteristics without requiring complex terrestrial site coordinates or multiple image correlations.
Solution Approach 2:
Instead of using terrestrial sites and working forward to determine vibrations, the invention inverts the approach by using a celestial reference (star) with known position and working backward to deduce satellite vibrations from the star's apparent motion in the image. This reversal simplifies the measurement process.
2Measurement precision
If methods using extensive image acquisition from terrestrial sites are used, then measurement precision is improved, but device complexity and processing complexity increase
Solution Approach 1:
The invention extracts the essential vibration information by observing a single star instead of processing multiple terrestrial sites. The star's known position serves as a reference point, and its image trail directly reveals vibration characteristics without requiring complex terrestrial site coordinates or multiple image correlations.
Solution Approach 2:
The invention uses a simplified model where the star's image trail serves as a direct copy of the vibration pattern. Instead of complex mathematical algorithms to correlate multiple images, the trail's oscillations directly represent the vibrations, making the measurement process much simpler.
3Measurement precision
If terrestrial sites are used for image acquisition, then measurement precision is improved, but reliability decreases due to cloud cover
Solution Approach 1:
The invention introduces a celestial intermediary (star) as the observation target instead of using terrestrial sites. This intermediary is not affected by cloud cover and provides a reliable, consistent reference point for vibration measurement, ensuring data acquisition can proceed regardless of weather conditions.
Solution Approach 2:
Instead of using terrestrial sites and working forward to determine vibrations, the invention inverts the approach by using a celestial reference (star) with known position and working backward to deduce satellite vibrations from the star's apparent motion in the image. This reversal simplifies the measurement process.
4Device complexity
If high-frequency vibrations are not characterized, then device complexity is reduced, but manufacturing precision deteriorates due to image degradation
Solution Approach 1:
The invention replaces complex mechanical vibration measurement systems with an optical observation method. Instead of using accelerometers or other mechanical sensors to measure high-frequency vibrations, the system uses the imaging system itself to capture the star's trail, which visually encodes the vibration information that can then be analyzed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient characterization of satellite vibrations, reducing image degradation by determining the optimal speed of gyroscopic actuators, thus improving image quality without the need for extensive image processing or cloud-dependent data acquisition.
Implementation Method 1
acquiring an image by means of the imaging system during the scanning in the second direction of said window, the image obtained having a trail corresponding to the selected star
Implementation Method 2
When the frame is pivoted to modify the orientation of the axis of rotation of the top, the reaction force generated makes it possible to modify the attitude of the satellite relative to an inertial reference frame
Implementation Method 3
The rotational movement of the tops of the gyroscopic actuators generates vibrations, generally having a high frequency of the order of 100 Hz, which propagate to the whole of the satellite and in particular to the imaging system
Data Source
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AI summary
The method involves extracting two coordinates of a selected star along directions (X, Y). A satellite is oriented using an amplitude system such that a visual axis of an imaging system is pointed towards one of the coordinates, and a window located around the other coordinate is scanned along one of the directions. An image is acquired using the imaging system during scanning along the window direction, where the obtained image presents a drag. The image is analyzed to determine a characteristic e.g. amplitude, of vibrations affecting the satellite from oscillations of the drag. An independent claim is also included for an installation for characterizing vibration affecting an observation satellite that is equipped with an imaging system having a visual axis and an amplitude system for orienting the visual axis of the imaging system, comprising a list of observable stars.