Dual-Focal Star Sensor Optical System
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Solution Overview
Problem
Existing star sensors face challenges in achieving high accuracy and resolution for spacecraft navigation due to the compromise between focal lengths required for field of view and optical resolution, often relying on mechanically moving parts that are costly and prone to errors.
Innovation Solution
The star sensor employs a dual optical system with a central lens and a mirror lens objective, both sharing the same optical axis, allowing simultaneous imaging of two light patterns onto a detector, enabling separate evaluation and assignment of fields of view without mechanical components, thereby achieving high resolution and large field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a small focal length is used for large field of view, then fast orientation is achieved, but optical resolution and positioning accuracy deteriorate
Solution Approach 1:
The optical system is segmented into multiple partial objectives (first partial objective with smaller focal length for wide field of view, second partial objective with larger focal length for narrow field of view), each optimized for specific functions. This allows simultaneous capture of both wide-area star patterns for fast orientation and detailed star images for precise positioning.
Solution Approach 2:
The patent adds a dimensional aspect by using multiple focal lengths simultaneously through different partial objectives rather than switching between single focal lengths. The sensor surface captures light patterns from multiple focal lengths concurrently, adding the dimension of multi-focal-length capability without mechanical switching.
2Measurement precision
If a large focal length is used for high resolution, then positioning accuracy is improved, but field of view and orientation speed deteriorate
Solution Approach 1:
The optical system is segmented into multiple partial objectives (first partial objective with smaller focal length for wide field of view, second partial objective with larger focal length for narrow field of view), each optimized for specific functions. This allows simultaneous capture of both wide-area star patterns for fast orientation and detailed star images for precise positioning.
Solution Approach 2:
The optical imaging system achieves multi-functionality by incorporating multiple partial objectives with different focal lengths that simultaneously image onto a single sensor surface. The system can perform both wide-field orientation and high-resolution positioning functions concurrently without requiring separate systems or mechanical switching.
3Adaptability or versatility
If automated switching between interchangeable lenses is implemented, then focal length adaptability is improved, but mechanical complexity and reliability deteriorate
Solution Approach 1:
The patent replaces the mechanical lens switching system with a stationary multi-objective optical design. Instead of mechanically moving parts to switch between lenses, multiple partial objectives are fixed in position with their respective beam paths directed to the sensor surface, eliminating mechanical complexity while maintaining focal length adaptability through optical design.
Solution Approach 2:
The patent merges multiple focal length capabilities into a single integrated optical system where multiple partial objectives simultaneously project onto the same sensor surface. This combines the functions of multiple interchangeable lenses into one stationary system, eliminating the need for mechanical switching while preserving adaptability.
4Adaptability or versatility
If zoom lenses are used for variable focal length, then focal length adjustability is improved, but mechanical complexity and precision deteriorate
Solution Approach 1:
The patent replaces the mechanical lens switching system with a stationary multi-objective optical design. Instead of mechanically moving parts to switch between lenses, multiple partial objectives are fixed in position with their respective beam paths directed to the sensor surface, eliminating mechanical complexity while maintaining focal length adaptability through optical design.
Solution Approach 2:
The patent creates a dynamic optical system where the effective focal length is determined by which partial objective's light pattern is being evaluated, not by mechanical movement. The system dynamically adapts between wide-field and narrow-field modes through computational separation of light patterns from different focal lengths rather than physical lens changes.
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 configuration allows for precise attitude control of spacecraft to less than one arc second, simplifying design, reducing weight, and enhancing the accuracy of position determination using star patterns.
Implementation Method 1
a central lens with a first focal length and a partial lens in the form of a lens surrounding it Mirror lens objective formed partial objective having a larger focal length with light patterns simultaneously imaging onto the sensor surface
Implementation Method 2
a partial lens in the form of a lens surrounding it Mirror lens objective formed partial objective having a larger focal length
Implementation Method 3
Mirror lens objective
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The star sensor (1) comprises an optical imaging system (2) with a lens (4) imaging a predetermined field of view (17,19) around an optical axis (7) on a sensor surface (6) of a detector (5) along an optical path (10,11). The lens has two partial lenses (8,9) with different focal lengths imaging simultaneously on the sensor surface with light patterns (15,22) separated partially from each other by a computing unit (3). An independent claim is included for a method for operating a star sensor.