Node-Synchronous Eccentricity Control for Satellite Slot Maintenance
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Solution Overview
Problem
Maintaining satellites in inclined geosynchronous orbits within precise longitude and inclination slots is challenging due to solar radiation pressure and other perturbing forces, leading to inefficient eccentricity control and interference issues.
Innovation Solution
Implementing node-synchronous eccentricity control by establishing and synchronizing inclination and eccentricity vectors for multiple satellites, allowing them to share a common longitude location through precise thruster maneuvers and timing adjustments, thereby minimizing eccentricity variations and maintaining orbital position within designated slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thruster systems with north-south and east-west aligned thrusters are used for stationkeeping, then inclination and drift control are achieved, but eccentricity control becomes inefficient and consumes excessive slot width
Solution Approach 1:
The patent changes the operational parameters of the existing thruster system by implementing node-synchronous eccentricity control that coordinates east-west thruster firings with the satellite's orbital position and inclination vector orientation. This transforms how the conventional thrusters are used, making them efficient for eccentricity control without requiring physical reconfiguration
Solution Approach 2:
The patent introduces dynamic adjustment of thruster firing timing and duration based on the satellite's real-time orbital parameters, including inclination vector orientation and node position. This dynamic control strategy allows the fixed thruster system to adapt to varying orbital conditions and efficiently control eccentricity
2Object-generated harmful factors
If multiple satellites are assigned to narrow geosynchronous slots (0.1-0.2 degrees longitude) to reduce interference, then frequency interference is minimized, but maintaining position within slots becomes increasingly difficult due to eccentricity and perturbing forces
Solution Approach 1:
The patent implements a feedback control mechanism where the satellite's orbital position, inclination vector, and eccentricity parameters are continuously monitored and used to adjust thruster firing commands. This closed-loop control ensures satellites remain within their assigned narrow slots despite solar radiation pressure and other perturbing forces
Solution Approach 2:
The patent performs preliminary stationkeeping maneuvers at strategically timed orbital positions (near nodes) to proactively correct eccentricity before it causes the satellite to drift outside its assigned slot. This preventive approach reduces the need for corrective maneuvers and improves position reliability
3Manufacturing precision
If sun-synchronous perigee stationkeeping strategy with double burn control maneuvers is used to compress eccentricity, then some eccentricity control is achieved, but control efficiency remains insufficient and east-west longitude excursion exceeds half the slot width
Solution Approach 1:
The patent employs periodic stationkeeping maneuvers synchronized with the satellite's orbital period and the regression of the inclination vector. By performing burns at specific orbital positions (near the nodes) at regular intervals, the system efficiently compresses eccentricity while accounting for the periodic nature of orbital perturbations
Solution Approach 2:
The patent uses the inclination vector as an intermediary reference to coordinate eccentricity control maneuvers. By aligning thruster firings with the inclination vector's orientation and the orbital nodes, the system achieves more efficient eccentricity control compared to fixed-time or fixed-position maneuvers
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 approach enables multiple satellites to co-locate at the same longitude, reducing interference and maintaining precise orbital positions, even under solar radiation pressure, by ensuring the eccentricity vector tracks the inclination vector, thus efficiently managing satellite positions within narrow slots.
Implementation Method 1
thrusters which are directed to generate forces through the spacecraft's center of mass. The north-south thrusters produce north-south velocity changes (ΔV) to control inclination. The east-west thrusters produce an east-west ΔV to control drift (change of longitude with time) and eccentricity.
Implementation Method 2
Attitude control is generally facilitated with momentum and/or reaction wheels whose momentum is periodically 'dumped' when the same (or different) thrusters are directed to generate turning moments about the spacecraft's center of mass.
Implementation Method 3
Such spacecraft often have large solar arrays and solar collectors, and therefore receive a strong solar force.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A first inclination vector associated with a first satellite (12) of the plurality of satellites is established. A second inclination vector associated with a second satellite (42) of the plurality of satellites is established. The first satellite and the second satellite are controlled, such that the first satellite and the second satellite are synchronized with a node.