Star Tracker Baffle With Dual Ports for Simultaneous Sun 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 washing out the view, requiring complex and weighty filter wheels that prevent simultaneous observation.

Innovation Solution

A star tracker design featuring a baffle with a star port and a sun port, both connected via a beam splitter, allowing for the attenuation of sun radiation while enabling simultaneous imaging of both the sun and stars without a filter wheel, by positioning the sun port at a 30-60 degree angle to the star port.

Engineering Contradictions & Design Principles

VSEngineering 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, and the filter prevents viewing of stars

Engineering Contradiction:
Improveability to view sunVSAvoidfilter wheel mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the single viewing path into two separate paths: a star port for viewing stars and a sun port for viewing the sun. Each port has its own optical path and filtering mechanism, allowing independent optimization for each target without requiring a filter wheel to switch between modes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The star tracker is designed to perform multiple functions simultaneously - it can view both stars and the sun at the same time through different ports. The single imaging sensor serves both stellar navigation and solar viewing functions, eliminating the need for mechanical filtering mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Illumination intensity

If the sun is viewed with a conventional star tracker, then the sun can be observed, but the intense radiation washes out the view and leads to no useful data

Engineering Contradiction:
Improvesun radiationVSAvoidview quality
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies different optical properties to different parts of the system: the sun port includes a filter specifically designed to attenuate intense solar radiation, while the star port remains unfiltered to maximize stellar light collection. This localized differentiation allows each port to be optimized for its specific viewing target.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

A filter is introduced as an intermediary element in the sun port's optical path to mediate between the intense solar radiation and the imaging sensor. This filter attenuates the radiation to suitable levels, enabling the sensor to capture useful data from the sun without being overwhelmed by excessive intensity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a filter wheel is used to enable sun viewing, then the star tracker can observe the sun, but the filter prevents simultaneous viewing of both the sun and stars

Engineering Contradiction:
Improvesun viewing capabilityVSAvoidsimultaneous observation capability
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The viewing system is segmented into two concurrent paths: the star port for stellar observation and the sun port for solar observation. Both paths feed into the same imaging sensor simultaneously, allowing the system to capture both star and sun images at the same time without mechanical switching.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system maintains continuous viewing capability for both stars and sun simultaneously. The dual-port design with separate optical paths allows uninterrupted observation of both targets at the same time, eliminating the intermittent operation required by filter wheel mechanisms.

Inventive Principle:
Principle #20Continuity of useful action

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 simultaneously view and image both the sun and stars, improving navigation and observation capabilities without increasing weight or complexity, and preventing radiation washout.

Implementation Method 1

configured to attenuate a magnitude of the second electromagnetic radiation

Methodology Applied
Scientific EffectAttenuation: Absorption (EM radiation)

Implementation Method 2

a lens disposed within the sun port configured to act as 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

Methodology Applied
Scientific EffectBeam splitting: Reflection

Data Source

PatentEP4109043B1Direct sun imaging star tracker
Publication Date: 2024.09.18 THE BOEING CO
  • EP4109043B1 patent drawingFigure 1
  • EP4109043B1 patent drawingFigure 2
  • EP4109043B1 patent drawingFigure 3A

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.