Satellite Orbit Normal Estimation via Magnetic Field Rotation
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Solution Overview
Problem
Current satellite attitude estimation devices for sun-synchronous orbits face reliability, performance, and mechanical arrangement issues, particularly in quasi-polar orbits, due to fragile terrestrial sensors and complex algorithms, with existing solutions like magnetic field models requiring on-board position awareness and complex initialization processes.
Innovation Solution
A device measuring the Earth's magnetic field and calculating the satellite's rotation speed to determine the orbit normal, using a magnetometer and gyrometer for accurate and autonomous attitude control, filtering measurements to reduce noise and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terrestrial sensors are used for satellite attitude estimation, then attitude control capability is provided, but reliability deteriorates due to sensor fragility during assembly, integration and test phases
Solution Approach 1:
The patent replaces fragile terrestrial sensors with a magnetic field-based attitude determination system. Instead of using mechanical/terrestrial sensors that are vulnerable during assembly and testing, the invention employs magnetometer measurements combined with mathematical algorithms to determine satellite attitude, thereby eliminating the reliability issues associated with physical sensors while reducing system complexity.
Solution Approach 2:
The satellite uses its own magnetic field measurements and onboard computational resources to determine its attitude independently. The system processes magnetic field data from the magnetometer through algorithms that calculate attitude quaternion and normal vector without requiring external terrestrial sensors, enabling the satellite to self-determine its orientation autonomously.
2Measurement precision
If terrestrial sensors are used for attitude estimation, then attitude information is obtained, but convergence time increases due to complex processing algorithms
Solution Approach 1:
The patent pre-loads terrestrial magnetic field model data into the satellite's memory before launch. This preliminary action allows the satellite to immediately access pre-computed magnetic field information without requiring complex real-time processing or external data transmission, significantly reducing convergence time while maintaining high measurement precision through the use of pre-prepared magnetic field models.
3Ease of operation
If terrestrial sensors are mounted on satellite appendages to avoid field of view interference, then sensor placement is optimized, but mechanical arrangement complexity increases and feasibility is reduced
Solution Approach 1:
The invention replaces the need for physically mounting sensors on satellite appendages with a magnetic field-based measurement system. The magnetometer can be placed in the satellite body without field of view constraints, and the magnetic field measurements are processed algorithmically to determine attitude, eliminating the mechanical complexity of sensor placement while maintaining operational ease.
4Reliability
If on-board terrestrial magnetic field model is used for attitude determination, then attitude control is achieved, but on-board position-in-orbit awareness is required increasing system complexity
Solution Approach 1:
The patent integrates the magnetic field model usage into the existing attitude determination system, making the magnetic field-based attitude control universally applicable without requiring separate position awareness subsystems. The magnetic field measurements and pre-loaded models work together to provide both attitude and position information through a unified processing framework, reducing overall system complexity while maintaining reliability.
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 solution provides a robust and reliable method for estimating the normal to the orbit, ensuring accurate satellite pointing and reducing interference from solar panels and antennas, maintaining equipment state during survival phases and optical payload operation.
Implementation Method 1
means for measuring the earth's magnetic field
Implementation Method 2
means for measuring the speed of rotation of the satellite
Data Source
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Figure 3~4
AI summary
The subject of the invention is a device for estimating the normal to an orbit of helio-synchronous type on which is positioned a satellite, said device comprising means for measuring the speed of rotation of the satellite (Osat) characterized in that it comprises:- means for measuring the earth's magnetic field (Bsat); - means for calculating the rotation of the magnetic field relative to the satellite (RB); - means for calculating the normal to the orbit from the speed of rotation of the satellite and from the rotation of the magnetic field. This type of device is incorporated in an attitude control system equipped with sensors and actuators to optimize the position of the satellite placed in orbit.