Celestial Positioning System for GPS-Denied Navigation
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Solution Overview
Problem
Current navigation systems are vulnerable in GPS-denied environments due to drift and error accumulation in inertial measurement units and limitations such as susceptibility to jamming, spoofing, and the need for pre-mapped areas in vision-based approaches, necessitating an alternative for reliable absolute positioning.
Innovation Solution
A Celestial Positioning System (CPS) that uses celestial objects like the Sun, Moon, planets, and stars to determine absolute position and orientation by measuring their polarization signatures and images in the sky, independent of GPS signals, incorporating an inertial measurement unit, clock, and image processing logic to calculate latitude, longitude, and heading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS is used for navigation, then position accuracy is improved, but vulnerability to signal denial and jamming increases
Solution Approach 1:
The patent introduces celestial objects (Sun, Moon, stars) as intermediary reference points to determine position without relying on GPS signals. By measuring the angular position of these celestial bodies and comparing with predicted positions from ephemeris data, the system achieves GPS-denied navigation capability while maintaining accuracy.
Solution Approach 2:
The patent replaces the electromagnetic-based GPS system with an optical measurement system that uses celestial bodies as references. This substitution eliminates vulnerability to RF jamming and signal denial while providing independent positioning capability through optical angular measurements.
2Adaptability or versatility
If inertial measurement units are used for dead reckoning, then navigation capability is maintained, but measurement drift and error accumulation increase
Solution Approach 1:
The patent implements a feedback mechanism where celestial body observations are continuously compared with predicted positions from ephemeris data. This feedback loop allows the system to detect and correct drift accumulation in the inertial measurement system, maintaining position accuracy over extended periods without GPS.
Solution Approach 2:
The patent uses pre-computed ephemeris data (predicted positions of celestial bodies) as a reference framework. By having these predictions available in advance, the system can immediately compare observed positions against expected values to detect and correct navigation errors, preventing drift accumulation.
3Measurement precision
If vision-based approaches are used for localization, then positioning is achieved, but requirement for pre-mapped areas increases complexity
Solution Approach 1:
The patent makes the positioning system universal by using celestial bodies that are always present in the sky as reference points. Unlike vision-based systems that require specific pre-mapped environments, this approach works in any open sky condition, providing universal positioning capability without requiring pre-mapped terrain or environmental data.
Solution Approach 2:
The patent extracts the positioning reference system from the ground-based environment and moves it to the celestial sphere. By using stars, Moon, and Sun as references, the system eliminates the need for pre-mapped terrestrial features, reducing complexity while maintaining positioning accuracy.
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
The CPS provides accurate 0.1-degree heading and <100 m position accuracy without prior maps, resistant to signal denial or interference, functioning in various environments and conditions, including daytime, twilight, and cloud cover, with potential applications in vehicles and personal navigation.
Implementation Method 1
measuring their polarization signatures and images in the sky
Data Source
AI summary
In a method of determining the position of an object, raw image data of the sky is recorded using a celestial imaging unit. The last known position, orientation, date, and time data of the object are obtained, and the position of a celestial body is measured. A latitude and longitude of the object is determined by matching the measured celestial body position to the expected celestial body position based on the input parameters. A system for determining a new position of an object comprises a celestial imaging unit configured to record image data of the sky, a signal processing unit, and a signal processing unit configured to receive and store in memory the image data received from the celestial imaging unit. The signal processing unit filters the image to find the positions of celestial objects in the sky. The signal processing unit is further configured to use roll and pitch from an IMU, and date and time from a clock to determine the object's position (latitude and longitude).