Satellite Constellation Repeating Ground Track for Continuous Coverage
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Solution Overview
Problem
Geosynchronous satellites have higher launch and maintenance costs and latency due to their altitude, and limited orbital slots restrict their number, necessitating alternative orbits for satellite communication systems.
Innovation Solution
A satellite communication system utilizing non-geosynchronous orbits (MEO or LEO) with a satellite constellation following a common, repeating ground track, allowing for continuous communication and reducing the complexity and cost of ground communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GEO satellites are used to provide satellite communication services, then continuous coverage and stationary appearance are achieved, but launch and maintenance costs increase due to high orbital altitude
Solution Approach 1:
The patent divides the single GEO satellite system into multiple LEO/MEO satellites operating in a constellation. Each satellite provides coverage for a specific time window, and together they provide continuous coverage through coordinated operation. This segmentation allows use of lower, more cost-effective orbits while maintaining service continuity.
Solution Approach 2:
The patent employs satellites in repeating ground tracks with periodic orbits (e.g., 100-minute periods). Satellites pass over the same ground locations at regular intervals, providing periodic coverage that, when coordinated across multiple satellites, achieves continuous service. This periodic action enables cost-effective LEO/MEO operations while maintaining reliability.
2Ease of operation
If GEO satellites are used to provide satellite communication services, then stationary appearance relative to ground stations is achieved, but communication latency increases due to high orbital altitude
Solution Approach 1:
The patent transitions from the vertical dimension (high GEO orbit at 35,786 km) to lower orbital dimensions (LEO at 160-2000 km or MEO at 2000-35,786 km). This dimensional change reduces the distance for RF communication, thereby reducing latency while using alternative strategies (multiple satellites, tracking antennas) to maintain operational ease.
Solution Approach 2:
The patent accepts dynamic satellite positions in LEO/MEO orbits rather than the static GEO appearance. Ground stations use tracking antennas that dynamically adjust to follow satellite movements across the sky. This dynamic approach reduces latency through lower orbits while maintaining ease of operation through automated tracking systems.
3Stability of the object's composition
If GEO satellites are used to provide satellite communication services, then orbital slot stability is achieved, but the number of operational satellites is limited by orbital slot availability
Solution Approach 1:
The patent changes the orbital parameters from GEO (35,786 km altitude, 24-hour period, equatorial inclination) to LEO/MEO (lower altitudes, shorter periods, various inclinations). This parameter change allows deployment of many more satellites since lower orbits have more available orbital slots and faster orbital periods enable more frequent passes and better coverage with fewer satellites per orbital plane.
Solution Approach 2:
The patent segments the satellite constellation into multiple orbital planes with satellites distributed across different inclinations and longitudes. This segmentation allows flexible deployment of numerous satellites in LEO/MEO orbits, overcoming the limited slot availability in GEO while maintaining stable, predictable ground tracks for each satellite group.
4Ease of manufacture
If LEO or MEO satellites are used instead of GEO satellites, then launch and maintenance costs are reduced, but ground communication system complexity increases due to satellite tracking requirements
Solution Approach 1:
The patent uses LEO/MEO satellites in repeating ground tracks that pass over the same locations at regular periodic intervals. This periodic action creates predictable, repeating sky tracks that ground stations can anticipate and track efficiently. The regularity reduces the complexity compared to non-repeating orbits, as tracking algorithms can exploit the periodic patterns.
Solution Approach 2:
The patent employs dynamic tracking systems at ground stations that automatically follow satellite movements. While the satellites move across the sky (requiring tracking rather than fixed antennas), modern electronic tracking systems manage this complexity efficiently. The dynamic tracking capability, combined with predictable repeating ground tracks, provides a practical balance between cost reduction and system complexity.
Data Source
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AI summary
A satellite communication system (100) in which a plurality of satellites (130) each transit about the Earth in a common mid- Earth orbit. The orbit may be configured such that each satellite of the plurality of satellites follows a common, repeating ground track (200) relative to the surface of the Earth (120). In turn, one or more repeating sky tracks (420) may be defined relative to at least one ground station (250) such that the ground station (250) is in continuous communication with at least one of the plurality of satellites (130). In an example, a ground station (250) may have visibility to a plurality of repeating sky tracks such that a plurality of discreet communication channels is provided that use different satellites for communication with user terminals of the satellite communications system (100).