LEO Constellation for GNSS Resilience
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Solution Overview
Problem
Current Global Navigation Satellite Systems (GNSS) face challenges such as interference, jamming, and spoofing, which compromise accuracy and integrity, particularly in aviation and military applications, and require costly infrastructure upgrades to enhance resilience and availability.
Innovation Solution
The implementation of a method using a Low Earth Orbit (LEO) constellation with carrier phase and coherent detection for resilient positioning, leveraging Receiver Autonomous Integrity Monitoring (RAIM) and existing user equipment with minimal hardware changes, to provide high precision, integrity, and rapid cold-start convergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS broadcast power is increased to improve signal availability and resilience against jamming, then reliability improves, but energy consumption and spectrum interference worsen
Solution Approach 1:
LEO satellites serve as intermediary nodes that receive weak GPS signals from MEO satellites and re-broadcast them with amplified power to users in jamming environments. This mediator approach allows signal enhancement without requiring the original GPS satellites to increase their already limited broadcast power, resolving the contradiction between signal availability and energy consumption.
Solution Approach 2:
The system changes the orbital parameter of the broadcasting satellite from MEO to LEO, exploiting the proximity advantage of LEO satellites to provide stronger signals to users. This parameter change enables improved signal availability and jamming resistance without increasing the power output of the original GPS satellites, thus avoiding the energy consumption penalty.
2Reliability
If LEO constellation is deployed to provide resilient positioning, then reliability against interference improves, but device complexity increases
Solution Approach 1:
The LEO satellites are designed with multi-functionality, serving both as communication relays for GPS signal distribution and as independent positioning sources. This universal design reduces overall system complexity by consolidating multiple functions into a single satellite platform, rather than requiring separate systems for signal relay and positioning.
Solution Approach 2:
The system implements self-service through user equipment that can autonomously select between direct GPS signals and LEO-relayed signals based on signal quality and availability. The receiver autonomously monitors signal integrity and switches sources without external intervention, reducing the complexity of ground-based monitoring and control infrastructure.
3Measurement precision
If carrier phase and coherent detection are used to achieve high precision positioning, then measurement precision improves, but ease of operation deteriorates due to hardware requirements
Solution Approach 1:
The system applies partial coherent detection by using coherent processing for carrier phase measurements only when needed for high-precision applications, while maintaining compatibility with standard non-coherent receivers for basic positioning. This partial application of the complex technique achieves high precision where required without mandating complex hardware upgrades across all users.
Data Source
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AI summary
Significant, cost-effective improvement is introduced for Position, Navigation, and Timing (PNT) on a global basis, particularly enhancing the performance of Global Navigation Satellite Systems (GNSS), an example of which is the Global Positioning System (GPS). The solution significantly improves performance metrics including the accuracy, integrity, time to acquire, interference rejection, and spoofing protection. A constellation of small satellites employing a low-cost architecture combined with improved signal processing yields an affordable enabler for spectrum-efficient transportation mobility. As air traffic management modernization transitions to a greater dependence on satellite positioning, the solution provides aviation users new protections from both intentional and unintentional interference to navigation and surveillance. And in response to an era in which intelligent transportation is under development for automobiles, reliable where-in-lane positioning enables new applications in connected and autonomous vehicles. New military capability increases PNT availability.