Star Tracker Steerable Baffle for Stray Light Management
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Solution Overview
Problem
Conventional star trackers face challenges in precision aiming and stray light management, particularly when navigating near bright objects like the sun or moon, limiting their ability to utilize a larger number of navigational stars and requiring complex mechanical mechanisms.
Innovation Solution
A star tracker with an electronically adjustable baffle assembly that selectively exposes a portion of its wide field-of-view camera to the scene, allowing for steerable and precise imaging of navigational stars while avoiding unwanted light, using a rotatable dome and curtain system to define a variable aperture and control transparency of elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wide field-of-view camera is used to capture more navigational stars, then the number of usable navigational stars increases, but stray light from bright objects like the sun or moon more easily reaches the sensor
Solution Approach 1:
The field of view is segmented into multiple zones using the adjustable baffle assembly. The baffle divides the wide FOV into a selected portion that captures navigational stars and blocks stray light paths. This segmentation allows the system to simultaneously achieve wide FOV for star capture while creating light-blocking segments to prevent stray light contamination.
Solution Approach 2:
The baffle assembly is made dynamically adjustable rather than fixed. By electronically controlling the baffle position and aperture size, the system can adapt the light-blocking configuration in real-time based on the positions of bright objects like the sun or moon. This dynamic adjustment allows optimal stray light rejection while maintaining wide FOV capability for capturing multiple navigational stars.
2Measurement precision
If a mechanically aimable star tracker is used to precisely target navigational stars, then positioning precision improves, but mechanical complexity and reliability issues increase
Solution Approach 1:
The patent replaces complex mechanical aiming mechanisms with an electronically controllable baffle assembly. Instead of using motors, gears, and mechanical linkages to physically aim the camera, the system uses electronic control to adjust the baffle position and aperture. This substitution eliminates mechanical wear, reduces complexity, and improves reliability while maintaining the ability to precisely target navigational stars within the wide FOV.
Solution Approach 2:
The system uses dynamic electronic control of the baffle assembly to achieve precise positioning without mechanical aiming mechanisms. The baffle can be rapidly and precisely positioned electronically to frame specific navigational stars, providing the positioning precision of mechanically aimable trackers while avoiding their mechanical complexity and reliability issues.
3Device complexity
If a fixed view angle star tracker is used to simplify mechanics, then device complexity reduces, but the number of usable navigational stars is limited
Solution Approach 1:
The patent introduces dynamic adjustability to the baffle assembly while keeping the camera body fixed and simple. The electronically controllable baffle can change the effective field of view angle and aperture size based on navigation needs, allowing the simple fixed camera structure to access multiple navigational stars by electronically reconfiguring the light path rather than physically repositioning the camera.
Solution Approach 2:
The baffle assembly segments the light path to selectively allow different portions of the sky to reach the sensor. By adjusting the baffle position and aperture, the system can present different selected portions of the wide field of view to the sensor, effectively providing multiple view angles from a single fixed camera position, thus increasing the number of accessible navigational stars without mechanical complexity.
Data Source
AI summary
A star tracker has an electronically steerable point of view, without requiring a precision aiming mechanism. The star tracker can be strapped down, thereby avoiding problems associated with precision aiming of mechanical devices. The star tracker images selectable narrow portions of a scene, such as the sky. Each stellar sighting can image a different portion of the sky, depending on which navigational star or group of navigational stars is of interest. The selectability of the portion of the sky imaged enables the star tracker to avoid unwanted light, such as from the sun.