Imaging Device In-Flight Calibration Using Celestial References
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Solution Overview
Problem
Existing methods for determining the positional information of targets relative to vehicles, such as ships and aircraft, face errors due to degradation of ground-based calibration during flight, leading to inaccuracies in pointing knowledge.
Innovation Solution
An imaging device is used to image celestial objects for in-flight calibration, determining the difference between expected and actual positions, which allows for the nulling of pointing errors and improved positional determination of non-celestial objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ground-based calibration is used for imaging device pointing, then initial pointing accuracy is achieved, but pointing accuracy degrades during flight over time
Solution Approach 1:
The system performs preliminary ground-based calibration before flight to establish initial pointing accuracy. This pre-calibration serves as a baseline that is later refined during flight using celestial references, combining the stability of ground calibration with the adaptability of in-flight adjustments.
Solution Approach 2:
The system continuously monitors the position of celestial objects (stars, satellites) and compares actual observed positions with expected catalog positions. This feedback loop enables real-time detection of pointing drift and automatic correction through calibration adjustments, maintaining accuracy throughout the flight duration.
2Measurement precision
If ground-based calibration is performed in advance, then initial pointing knowledge is established, but error accumulates during flight operations
Solution Approach 1:
The calibration process transitions from a discrete ground-based event to a continuous in-flight process. By continuously imaging celestial objects and comparing their positions with catalog data, the system maintains up-to-date pointing knowledge throughout the entire flight, eliminating the time gap between calibration and actual use.
Solution Approach 2:
The imaging device calibrates itself during flight operations by using celestial objects as natural references. The system automatically detects pointing errors by comparing observed celestial positions with expected positions and performs self-correction without requiring external intervention or ground-based recalibration.
3Measurement precision
If in-flight celestial calibration is implemented, then pointing accuracy is maintained during flight, but system complexity increases
Solution Approach 1:
The imaging device serves dual purposes: it performs both operational imaging of targets and calibration imaging of celestial objects. The same hardware components (imager, processor, database) are used for both functions, eliminating the need for separate calibration equipment and reducing overall system complexity.
Solution Approach 2:
Celestial objects (stars, satellites) serve as intermediary reference points that bridge the gap between the imaging device and the Earth-based coordinate system. These natural references provide a stable, predictable framework for maintaining pointing accuracy without requiring complex ground-based infrastructure or active cooperation from external systems.
4Measurement precision
If celestial objects are used for calibration, then real-time pointing correction is achieved, but dependency on visible celestial objects is required
Solution Approach 1:
The calibration system dynamically adapts to different operational conditions by selecting appropriate celestial references based on visibility, time of day, and flight phase. The system can switch between different types of celestial objects (stars, planets, artificial satellites) and adjust calibration frequency based on environmental conditions and mission requirements.
Data Source
AI summary
A method of determining position of an object using an imaging device includes imaging a celestial object using an imaging device. A difference between an expected position of the celestial object and an actual position of the celestial object is determined. Pointing of the imaging device is in-flight calibrated to improve position determining by nulling the difference between the expected position of the celestial object and the actual position of the celestial object. Systems for determining position of an object relative to a vehicle are also described.