Spacecraft Reference Trajectory Correction via Drag Acceleration
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Solution Overview
Problem
Current methods for correcting spacecraft reference trajectories during flight, such as reference trajectory guiding, closed form guidance, and real-time trajectory generation, face challenges including high data processing requirements, large data storage needs, and inaccuracies due to deviations from predefined trajectories, especially for capsule-type spacecraft that cannot generate significant lift forces.
Innovation Solution
A flight control device that calculates and corrects the reference trajectory based on the ratio of the distance from the current position to the target position using drag acceleration, allowing for accurate trajectory correction without high data processing performance, applicable to both winged and wingless spacecraft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reference trajectory guiding method is used with table data stored in advance, then the data processing performance requirement is reduced, but the storage device must store tremendous volume of data and analysis required in advance becomes large-scale
Solution Approach 1:
The patent extracts only the essential parameter (drag acceleration) from the complex table data system, eliminating the need for storing tremendous volumes of pre-analyzed trajectory data while maintaining the ability to generate accurate reference trajectories during flight
Solution Approach 2:
The reference trajectory is divided into multiple phases, and drag acceleration is calculated separately for each phase based on current flight conditions, allowing real-time adaptation without requiring complete pre-computation of all possible scenarios
2Device complexity
If the reference trajectory is generated on the Earth in advance without correction, then the data processing load during flight is reduced, but the error increases until the spacecraft reaches the target position due to deviation from the reference trajectory
Solution Approach 1:
The patent implements feedback by continuously calculating the ratio between the actual distance from current position to target and the distance based on the reference trajectory, then using this ratio to correct the drag acceleration and update the reference trajectory in real-time, ensuring high accuracy throughout the flight
Solution Approach 2:
The reference trajectory is transformed from a static pre-generated path into a dynamic trajectory that adapts in real-time based on current flight conditions and actual position, allowing the system to maintain accuracy without complex pre-computation
3Device complexity
If the closed form guidance method is used with approximate formulas, then the calculation process is simplified, but the error increases as the deviation of the spacecraft from the reference trajectory becomes greater
Solution Approach 1:
The patent applies correction only when necessary - by calculating the ratio of actual distance to reference distance and applying drag acceleration correction based on this ratio, providing sufficient correction for deviations without over-complicating the calculation for cases where the spacecraft remains close to the reference trajectory
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 accurate arrival at the target position by simplifying the calculation of drag acceleration to correct the reference trajectory, reducing errors and processing load, and enhancing accuracy for both winged and wingless spacecraft.
Implementation Method 1
In the atmosphere, the spacecraft changes inclination of its body so as to change lift force generated on the body, thereby changing the velocity
Implementation Method 2
the reference trajectory is identified based on the drag acceleration and the velocity (or energy) of the spacecraft
Data Source
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AI summary
An object of the present invention is to correct a reference trajectory based on a distance from a current position to a target position in a spacecraft in flight without using a data processor with high data processing performance. A CPU (22) included in the spacecraft generates a reference trajectory which is a trajectory for allowing the spacecraft in flight to arrive at the target position on a celestial body with the atmosphere, and which is identified based on velocity or energy of the spacecraft and on drag acceleration of the spacecraft. The CPU (22) calculates a ratio between the range that is a distance from the current position based on the reference trajectory to the target position, and the real range that is a real distance from a current position to the target position, and corrects the reference trajectory by calculating the drag acceleration in the reference trajectory using the calculated ratio.