Spacecraft Formation Control Using Delta DOR Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current deployment techniques for spacecraft in formation flight often result in uncertain visibility and collision risks due to unpredictable inter-satellite distances and insufficient maneuvering capabilities, particularly during launches and when inter-satellite communication is lost.
Innovation Solution
A ground-based control system that simultaneously determines the orbital positions of spacecraft with high precision using Delta DOR technique and calculates maneuvers to position them accurately within a chosen formation configuration, incorporating relative metrology and collision avoidance measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If deployment is initiated by launching composites with separate launchers, then multiple spacecraft can be deployed, but inter-satellite distances become unpredictable and visibility between satellites is not guaranteed
Solution Approach 1:
The patent implements a feedback control system where ground stations continuously measure the positions of deployed spacecraft and transmit this information back to the control system. The control system then calculates and transmits maneuver commands to adjust spacecraft positions, creating a closed-loop feedback mechanism that maintains precise formation geometry despite using multiple launchers
Solution Approach 2:
The patent introduces ground-based measuring stations and control systems as intermediaries between the multiple launchers and the final formation. These intermediaries coordinate the deployment process, measure positions with high precision, and manage communications to ensure all spacecraft achieve their designated positions regardless of launcher variations
2Reliability
If spacecraft are deployed with large inter-satellite distances, then communication between ground station and spacecraft is maintained, but visibility between satellites is lost and RF link may be interrupted
Solution Approach 1:
The patent employs dynamic adjustment of inter-satellite distances based on formation phase. During deployment, larger distances are tolerated for ground communication, but once in formation, the system dynamically adjusts positions to maintain distances within RF communication range while preserving ground communication through coordinated maneuvers
Solution Approach 2:
The system changes the parameter of inter-satellite distance based on operational phase. During deployment, distances can be larger; during formation operations, distances are adjusted to specific values that ensure both ground communication reliability and inter-satellite RF link connectivity
3Ease of operation
If spacecraft maneuvering capacity is limited, then deployment simplicity is maintained, but collision avoidance capability is insufficient
Solution Approach 1:
The patent implements preliminary collision risk assessment and maneuver planning before spacecraft converge to their final positions. The ground control system calculates potential collision scenarios in advance and pre-computes avoidance maneuvers, allowing spacecraft with limited maneuvering capacity to safely navigate the deployment process without requiring complex real-time decision-making
Solution Approach 2:
The ground-based control system acts as an intermediary that manages collision avoidance for spacecraft with limited maneuvering capacity. The intermediary calculates safe trajectories and transmits maneuver commands to spacecraft, effectively providing collision avoidance capability that the spacecraft themselves cannot generate independently
Data Source
AI summary
The system has a calculation module (MC1) determining operations, intended to position each of reference and follower space vehicles (ES1, ES2) at a chosen instant in a chosen position with respect to a reference path (TR), based on orbital positions of the vehicles by considering a time law of the reference vehicle for placing a formation in a chosen configuration. Calculation units (MC21, MC22) communicate anti-collision operations, determined when a risk of collision of one vehicle with the other vehicle exceeds a chosen value, with orbit correction modules (MCO1, MCO2).