Satellite Constellation Design for Full Earth Coverage
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Solution Overview
Problem
Current satellite constellation designs, particularly for polar orbiting satellites, face challenges in achieving full earth coverage with minimal gaps, as existing methods like the 'streets of coverage' technique fail to provide uniform coverage, leading to significant gaps and inefficiencies in coverage patterns.
Innovation Solution
The proposed method uses a scan over two perpendicular angular planes, employing an analytic technique to determine the minimum number of satellites required for continuous, complete earth coverage, focusing on efficient constellation designs that provide contiguous or overlapping coverage, especially in the equatorial plane, which ensures full coverage over every other latitudinal plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If geosynchronous satellites are used to provide frequent coverage, then coverage frequency is improved, but measurement resolution deteriorates due to high altitude
Solution Approach 1:
The patent divides the earth coverage task into multiple segments by using multiple low-altitude polar orbiting satellites instead of a single high-altitude geosynchronous satellite. Each satellite covers a specific portion of the earth, and together they provide complete coverage with high resolution. This segmentation allows maintaining high measurement precision while achieving frequent coverage through the coordinated operation of multiple satellites.
Solution Approach 2:
The patent transitions from using satellites in a single orbital plane (geosynchronous equatorial orbit) to using satellites in multiple orbital planes (polar orbits with different inclinations). This dimensional change in orbital configuration allows low-altitude satellites to cover all latitudes including polar regions, providing both high resolution and frequent global coverage that cannot be achieved from a single geosynchronous position.
2Measurement precision
If low earth orbit satellites are used to provide high spatial resolution, then measurement resolution is improved, but coverage frequency deteriorates to once per half day to a few days
Solution Approach 1:
The patent merges multiple low-altitude polar orbiting satellites into a coordinated constellation that operates together to provide continuous global coverage. By combining the coverage areas and observation times of multiple satellites in different orbital planes, the system achieves both high spatial resolution (inherited from low altitude) and high coverage frequency (achieved through multiple satellites passing over different regions), resolving the contradiction between resolution and coverage frequency.
Solution Approach 2:
The patent ensures continuous useful action by designing the satellite constellation so that as one satellite completes its orbit and exits a region, another satellite is already positioned to cover that same region. This continuous handover between satellites maintains uninterrupted high-resolution monitoring of the entire earth, eliminating the gaps that would occur with a single low-altitude satellite.
3Area of stationary object
If geosynchronous satellites are positioned to cover high latitudes, then coverage area is improved, but measurement resolution deteriorates significantly for latitudes greater than 60 degrees
Solution Approach 1:
The patent applies local quality by positioning low-altitude satellites in polar orbits that pass directly over high-latitude regions, providing locally optimized high-resolution coverage where it is most needed. Unlike geosynchronous satellites that view high latitudes from a distant, oblique angle, the polar orbiting satellites fly overhead, maintaining consistently high resolution across all latitudes including those greater than 60 degrees, while still covering the entire global area.
4Area of stationary object
If more satellites are added to achieve full earth coverage with low altitude satellites, then coverage completeness is improved, but system cost increases
Solution Approach 1:
The patent employs dynamic orbital configurations where satellites operate in inclined polar orbits that naturally provide varying coverage patterns as they orbit. This dynamic approach allows a smaller number of satellites to achieve complete global coverage compared to static configurations, as each satellite's orbital plane and ground track change continuously, providing different viewing angles and coverage areas that complement each other over time.
Data Source
AI summary
A system and method for highly efficient constellations of satellites which give single, double, . . . k-fold redundant full earth imaging coverage, or k-fold coverage for latitudes greater than any selected latitude is given for remote sensing instruments in short periods of time, i.e., continuous coverage, as a function of the parameters of the satellite and the remote sensing instrument for many different types of orbits. A high data rate satellite communication system and method for use with small, mobile cell phone receiving and transmitting stations is also provided. Satellite instrument performance models, full and partial satellite constellation models, and satellite cost models are disclosed and used to optimize the design of satellite systems with vastly improved performance and lower cost over current major satellite systems.