Satellite Attitude Maneuver Avoidance Trajectory
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Solution Overview
Problem
Satellites face challenges in changing their orientation to avoid damaging or disturbing areas like the Sun and Moon during maneuvers, leading to mission interruptions and reduced autonomy, as current solutions either deactivate instruments or de-optimize missions.
Innovation Solution
A method that calculates attitude maneuvers using a spherical trajectory to avoid prohibited zones by determining tangents and intersection points, ensuring the pointing axis follows a convex avoidance trajectory, with recursive determination of additional points if necessary, to maintain instrument functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the satellite activates on-board monitoring to interrupt the mission when pointing towards prohibited zones, then the instruments are protected from damage, but the mission availability and productivity are significantly reduced
Solution Approach 1:
The method calculates avoidance trajectories in advance by determining tangents from departure and arrival points to prohibited zones, identifying avoidance points before the maneuver is executed. This preliminary planning allows the satellite to automatically navigate around prohibited zones without interrupting the mission, thus protecting instruments while maintaining continuous operation
Solution Approach 2:
The satellite autonomously determines its own avoidance trajectory by calculating tangents and selecting avoidance points based on predefined criteria. The system uses onboard resources (processing power, stored prohibited zone data) to self-manage the avoidance maneuver without external intervention, maintaining mission continuity while ensuring instrument protection
2Reliability
If the satellite rejects certain scores in advance to avoid prohibited zones, then the risk of instrument damage is reduced, but the mission possibilities and adaptability are reduced
Solution Approach 1:
The method dynamically determines avoidance trajectories based on real-time parameters including departure point, arrival point, and identified prohibited zones. The system adapts the avoidance path to the specific maneuver requirements by calculating tangents from the actual departure and arrival positions, rather than using fixed predetermined restrictions. This dynamic approach preserves mission flexibility while ensuring instrument protection
Solution Approach 2:
The system changes the operational parameters by introducing avoidance points calculated from geometric tangents to prohibited zones. Instead of rejecting entire score sets or mission possibilities, the method modifies the trajectory parameters (position, orientation) to navigate around prohibited areas, thus maintaining mission adaptability while protecting instruments
3Productivity
If the satellite follows a direct trajectory from departure to arrival, then the maneuver time is minimized, but the risk of pointing towards prohibited zones increases
Solution Approach 1:
The method uses spherical geometry to determine avoidance trajectories on the attitude sphere. By calculating tangents from departure and arrival points to the circular prohibited zone and finding their intersection, the system creates a curved avoidance path that naturally circumvents the prohibited area. This geometric approach efficiently balances maneuver time with protection requirements
4Productivity
If the satellite determines avoidance points using tangents from departure and arrival points, then the avoidance trajectory is optimized, but the calculation complexity increases
Solution Approach 1:
The avoidance trajectory calculation is segmented into distinct steps: determining tangents from the departure point to the prohibited zone, determining tangents from the arrival point to the prohibited zone, finding the intersection point of these tangents, and verifying the avoidance point is not too far from the prohibited zone. This stepwise segmentation makes the complex geometric calculation more manageable and implementable
Data Source
Figure 1~2a
Figure 2b
Figure 3
AI summary
The invention relates to a method for calculating attitude maneuvers of a system, from a starting point (A) to an arrival point (B), under constraint of pointing directions to be avoided which correspond to at least one prohibited zone towards which the craft points along a pointing axis following an initial trajectory called unconstrained going from the starting point (A) to the arrival point (B), the method comprising steps of E1) determination of at least one point called avoidance, such that an avoidance trajectory of the pointing axis deviates from the initial trajectory (AB) by passing through the avoidance point to avoid the prohibited zone; E5) determination of the maneuvers of the satellite allowing the pointing axis to follow the avoidance trajectory, E6) selection, among the maneuvers determined, according to the direction of bypassing the prohibited zone(s), of the best sequence of maneuvers to be carried out.