Spacecraft Flight Direction Sensing Using Celestial Imaging
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Solution Overview
Problem
Small satellites face challenges in determining flight direction due to limited space and the inefficiency of existing sensors, which become ineffective at higher altitudes where atmospheric density is low, requiring bulky and complex systems that are not suitable for low-weight, low-volume spacecraft.
Innovation Solution
A method and system using a small, lightweight imaging detector and processor, similar to those in optical mice, to capture and process sequential images of a celestial body, determining flight direction by analyzing image feature movement, which can be combined with a nadir direction finder and gyroscope for accurate orientation, functioning at any altitude below geostationary orbit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensing approaches are used to determine flight direction, then the system works well at low altitudes where atmospheric density is detectable, but the system becomes ineffective at altitudes greater than 1,000 km where atmospheric density drops rapidly
Solution Approach 1:
The patent transitions from pressure-based sensing (which depends on atmospheric density parameters) to optical imaging sensing (which depends on light reflection parameters from celestial bodies). This parameter change allows the system to operate reliably across a wide altitude range from LEO to GEO, overcoming the limitation of pressure sensors that fail above 1,000 km where atmospheric density becomes too low for detection.
2Measurement precision
If multiple sensors and complex imaging systems are used for flight direction sensing, then measurement accuracy is improved, but the system becomes prohibitively bulky and unsuitable for small satellites
Solution Approach 1:
The patent extracts only the essential function needed for flight direction sensing - capturing images of celestial bodies and analyzing their movement - rather than using complex multi-sensor systems. By taking out just the necessary imaging and processing components, the system achieves adequate measurement precision with minimal volume, making it suitable for small satellites with limited space.
Solution Approach 2:
The patent uses simple imaging detectors that capture optical images of celestial bodies, creating a simplified copy of the complex multi-sensor approaches. Instead of using multiple specialized sensors (sun sensors, star sensors, horizon sensors), the system uses basic imaging detectors that record light patterns, which are then processed to extract flight direction information, achieving comparable functionality with reduced complexity and volume.
3Weight of moving object
If lightweight and compact sensor systems are used for small satellites, then launch cost is reduced, but the system must still provide reliable flight direction sensing across various altitudes
Solution Approach 1:
The patent employs imaging detectors that serve multiple functions: they capture images of celestial bodies for flight direction determination, can potentially be used for other navigation purposes, and work across a universal altitude range from LEO to GEO. This multi-functionality ensures that the lightweight system maintains reliability across various operating conditions and altitudes without requiring additional specialized sensors.
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 cost-effective and efficient flight direction sensing for spacecraft, providing a compact and reliable system that functions across various altitudes without requiring orbital data or time information, suitable for small satellites.
Implementation Method 1
imaging at least a portion of a celestial body onto the at least one imaging detector; acquiring, by the at least one imaging detector, sequential images of at least a portion of the celestial body
Data Source
AI summary
Certain embodiments of the invention may include systems, methods, and apparatus for sensing flight direction of a spacecraft. According to an example embodiment of the invention, a method is provided for determining flight direction of a spacecraft. The method includes providing at least one imaging detector associated with a spacecraft; imaging at least a portion of a celestial body onto the at least one imaging detector; acquiring, by the at least one imaging detector, sequential images of at least a portion of the celestial body; and determining the spacecraft flight direction relative to the celestial body based at least in part on processing the sequential images, wherein the processing is performed by one or more computer processors.