Satellite Image Shake Compensation via External Laser Reference
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Solution Overview
Problem
Current methods for characterizing image shake in satellite-based observation systems are complex, costly, and weight-penetrating, often relying on additional devices like laser metrology or star tracking, which are impractical due to vibration-induced line-of-sight variations during exposure.
Innovation Solution
An image capture method using an optical sensing device rigidly connected to the imaging system, pointing towards a distant laser source for characterizing line-of-sight variations, allowing for real-time compensation with a mobile mirror to reduce image shake, without increasing system complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser metrology device is added to constitute a pseudo-inertial reference, then image shake can be characterized, but device complexity and weight increase
Solution Approach 1:
The patent introduces an intermediary element - a distant laser source - that serves as a reference for measuring line-of-sight variations. This external laser source acts as a mediator between the imaging system and the vibration characterization process, allowing measurement without adding complex metrology devices to the satellite itself
Solution Approach 2:
The patent replaces the mechanical laser metrology device with an optical-based solution using a distant laser source. Instead of using mechanical reference systems on board, the invention uses optical interference patterns from an external laser to characterize vibrations, thereby reducing mechanical complexity
2Measurement precision
If a laser metrology device is added to constitute a pseudo-inertial reference, then image shake can be characterized, but weight increases
Solution Approach 1:
The distant laser source serves as an external intermediary that eliminates the need for heavy on-board metrology equipment. By using an external reference, the satellite can characterize image shake without carrying additional weight-penalty hardware
Solution Approach 2:
The patent extracts the reference function from the satellite system itself and places it externally in the form of a distant laser source. This separation removes the weight burden from the satellite while maintaining the capability to measure line-of-sight variations
3Productivity
If images of stars are acquired at high rate, then line of sight variations can be characterized, but signal-to-noise ratio becomes insufficient due to low luminosity
Solution Approach 1:
The patent changes the key parameter of reference source luminosity by using a laser source instead of stars. Lasers provide high luminosity that enables rapid image acquisition at high frame rates while maintaining sufficient signal-to-noise ratio for precise direction measurement
Solution Approach 2:
The patent utilizes the specific wavelength characteristics of laser light (monochromatic and coherent) to create high-contrast interference patterns that can be detected rapidly and precisely, unlike the broadband, low-luminosity starlight
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
Effectively characterizes and compensates for image shake with high precision and frequency, reducing the amplitude of target zone displacements in acquired images without adding complexity or weight to the imaging system.
Implementation Method 1
the optical detection device is pointed, during an image capture sequence by the imaging system, towards an optical communication terminal by laser signals which is external to the wearer, and which constitutes the distant radiation source
Data Source
Figure 1a~1b
Figure 2~3b
AI summary
The method involves forming, within a focal plane, an image of a radiation source (100) i.e. external laser source, remote from a carrier e.g. terrestrial satellite (S), by an optical detection device. Displacement of the image in the plane is detected by the device to provide characterization of variations in a sight line of an imaging system (1). The device is pointed toward a free space laser optical communication terminal arranged external to the carrier, during an image capturing sequence of the system, and utilized to form the source. An independent claim is also included for an onboard imaging assembly of a carrier such as land vehicle, aircraft, ship or satellite.