Star Tracker Sun Port Beam Splitter Simultaneous Imaging
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Solution Overview
Problem
Conventional star trackers cannot simultaneously view the sun and stars due to the intense radiation from the sun overpowering the view of the stars, requiring complex mechanisms like filter wheels that increase weight and complication.
Innovation Solution
A direct sun imaging star tracker system that includes an imaging sensor and a baffle with a star port and a sun port, along with a beam splitter, allowing the sensor to receive and combine electromagnetic radiation from both environments, attenuating the sun's radiation to prevent washout and enable simultaneous imaging of the sun and stars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional star tracker uses a filter wheel to view the sun, then the star tracker can view the sun in certain configurations, but the mechanism increases device complexity and weight
Solution Approach 1:
The patent extracts the sun viewing capability from the main star tracker optical path by introducing a separate sun port with dedicated attenuation filters. This allows the sun to be viewed through a specialized path while stars are viewed through the main port, eliminating the need for a filter wheel mechanism to switch between viewing modes.
Solution Approach 2:
The patent introduces an intermediary attenuation mechanism (fixed filters in the sun port) that mediates between the intense sunlight and the imaging sensor. This intermediary element permanently reduces solar intensity to acceptable levels without requiring mechanical movement or complex control systems.
2Adaptability or versatility
If a conventional star tracker uses a filter wheel to view the sun, then the star tracker can view the sun, but the filter prevents viewing of stars, preventing simultaneous viewing of both the sun and the stars
Solution Approach 1:
The patent segments the star tracker into two independent viewing paths: a main port for star viewing and a separate sun port for solar viewing. Each port has its own optical path and attenuation characteristics, allowing both to operate simultaneously without interfering with each other. The beam splitter combines these separate paths into a single imaging sensor input.
Solution Approach 2:
The imaging sensor serves multiple functions by receiving input from both the main port (for star tracking) and the sun port (for solar viewing) simultaneously. This multi-functional capability allows the single sensor to perform both star navigation and sun observation without requiring separate sensors or sequential operation.
3Illumination intensity
If the star tracker views the sun directly, then the star tracker can observe the sun, but the intense radiation washes out the view and leads to no useful data
Solution Approach 1:
The patent applies different optical qualities to different viewing paths: the main port uses high-transmission optics optimized for faint star light, while the sun port uses dedicated attenuation filters optimized for reducing intense solar radiation. Each path is locally optimized for its specific viewing target, allowing both faint stars and bright sun to be imaged with appropriate quality.
Solution Approach 2:
The patent changes the transmission parameter of the sun port path by introducing attenuation filters that reduce solar intensity by several orders of magnitude. This parameter modification transforms the overly intense sunlight into a level suitable for the imaging sensor, preserving data quality while maintaining the ability to observe the sun.
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
Enables the star tracker to navigate using stars while observing the sun without the need for a filter wheel, reducing weight and complexity, and providing a reliable and efficient method for imaging both celestial bodies simultaneously.
Implementation Method 1
a sun port, configured to receive second electromagnetic radiation associated with a second viewing environment via a second path and configured to attenuate a magnitude of the second electromagnetic radiation
Implementation Method 2
a beam splitter, configured to receive the first electromagnetic radiation of the first path and the second electromagnetic radiation of the second path and configured to combine the first electromagnetic radiation and the second electromagnetic radiation into the combined viewpath
Data Source
AI summary
Described are systems and methods for direct sun imaging by a star tracker. Disclosed in a certain example is a direct sun imaging star tracker that includes an imaging sensor and a baffle. The baffle includes a star port, a sun port, and a beam splitter. The star port is configured to image first viewing environment while the sun port is configured to image a second viewing environment that includes the sun. The beam splitter is configured to combine electromagnetic radiation from the star port and the sun port into a combined image. In various examples, the systems and techniques described herein allow a star tracker to simultaneously view both the sun and the stars.