LEO Satellite Constellation Optimization for ARAIM Integrity
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Solution Overview
Problem
Current satellite navigation augmentation systems face challenges in providing global centimeter-level positioning and fast convergence services, especially in complex environments, due to limitations in ground station infrastructure and the need for reduced dependence on overseas stations, and there is a lack of integrity monitoring in Low Earth Orbit (LEO) satellite navigation enhancement systems.
Innovation Solution
A constellation configuration optimization method for a LEO satellite augmentation system using a non-dominated sorting genetic algorithm with an elite strategy to optimize LEO satellite constellation configuration parameters, such as orbit inclination, altitude, ascending intersection right ascension, and mean anomaly, to reduce vertical protection levels and enhance ARAIM protection levels, thereby improving the availability and integrity of navigation services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ground station auxiliary information enhancement systems are used, then regional navigation enhancement can be achieved, but global centimeter-level positioning and fast convergence service cannot be realized due to territory limitations
Solution Approach 1:
The patent transitions from ground-based augmentation to space-based LEO satellite augmentation, moving the enhancement system from terrestrial dimension to orbital dimension. This enables global coverage by utilizing satellites' movement across different geographic regions, overcoming the territorial limitations of ground stations while maintaining centimeter-level positioning reliability.
Solution Approach 2:
LEO satellites serve as intermediary platforms carrying navigation enhancement payloads that broadcast correction data and integrity information to airborne receivers. These satellites mediate between ground-based reference systems and mobile users, providing global access to precise positioning services without requiring dense ground infrastructure everywhere.
2Reliability
If LEO satellite constellation configuration is not optimized, then system implementation is simpler, but vertical protection levels are higher and ARAIM availability is reduced
Solution Approach 1:
The patent systematically optimizes key constellation parameters including orbital altitude (1600-2000 km range), inclination angles (50-70 degrees), satellite spacing, and phasing to minimize vertical protection levels. By adjusting these parameters within specific ranges, the system achieves optimal geometric distribution of satellites relative to airborne receivers, thereby reducing protection levels and enhancing ARAIM availability.
Solution Approach 2:
The optimized constellation configuration creates dynamic geometric relationships between LEO satellites and airborne receivers as satellites move along their orbital paths. This dynamic geometry ensures that favorable satellite-receiver configurations are maintained over time, continuously reducing vertical protection levels and improving integrity monitoring performance throughout the satellites' orbital cycles.
3Reliability
If LEO satellite navigation enhancement system is deployed without integrity monitoring optimization, then deployment is faster, but integrity monitoring capability is lacking and ARAIM receiver availability is affected
Solution Approach 1:
The patent incorporates integrity monitoring functionality directly into the LEO satellite navigation enhancement payload design from the outset, rather than adding it later. The constellation configuration is pre-optimized specifically to support ARAIM integrity requirements, with satellite geometry and distribution planned to ensure adequate visibility and protection level reduction for integrity monitoring operations.
Solution Approach 2:
The LEO satellites are designed with multi-functional payloads that simultaneously provide navigation enhancement, integrity monitoring, and positioning services. This universal approach allows a single satellite constellation to fulfill multiple functions, eliminating the need for separate integrity monitoring infrastructure and enabling faster deployment while maintaining comprehensive ARAIM support.
Data Source
AI summary
A constellation configuration optimization method of a low earth orbit (LEO) satellite augmentation system for an ARAIM application includes: 1, traversing vertical protection levels after all subset solutions and fault modes under the condition that integrity risk and continuity risk are equally distributed, and determining the constraint conditions of LEO satellite constellation configuration parameters; 2, determining objective functions of LEO satellite constellation configuration parameters x1, x2, x3, x4, eliminating calculated values of abnormal vertical protection levels, and screening initial populations of the parameters x1, x2, x3, x4; 3, calculating fitness of the objective functions; 4, starting from a second generation population, merging a parent population with an offspring population to form a new offspring population; 5, performing local optimal selection on the new offspring population, screening out a maximum value of the objective functions as an optimal offspring, and repeating step 4 until a genetic algebra is less than a maximum genetic algebra.