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Radio-Frequency Signal Augmentation to Reduce PNT Jamming and Spoofing Risks

Project Description:  GNSS is vulnerable to jamming because the power of GNSS signals received near the Earth’s surface is extremely weak, as low as a tenth of a millionth of a billionth of a Watt.  Higher power signals from Low-Earth Orbiting (LEO) satellites intended for communication can be used as an opportunistic means of navigation, but only with significant risks because the LEO service providers have no commitment to navigation users.  In contrast, recently-modernized and emerging dedicated LEO constellations can provide positioning navigation and timing (PNT) with quantifiable performance. In particular, CARNATIONS industrial partners Satelles, Inc. and Xona Space Systems, two PNT LEO satellite constellation operators, provide signals that are secure, powerful, reliable, and independent of GNSS.  This project aims at (1) designing LEO satellite-based resilient PNT (R-PNT) algorithms and (2) evaluating them for transportation applications. 

1.  We propose to develop new methods to combine LEO and GNSS satellite signals. Navigation continuity is maximized when signals are tightly integrated as early as possible in the navigation system’s processing pipeline. However, preserving the independence of data sources is key to detecting insidious spoofing threats by checking for inconsistencies between individual pieces of information. Loosely-coupled implementations can be more integrity-efficient than tightly-coupled ones for GNSS fault detection and exclusion (FDE) in transportation applications.  The proposed research aims at deriving optimal LEO/GNSS algorithms that maximize integrity while maintaining continuity.  These algorithms depend on robust models of satellite signal uncertainty that we will also establish. 

2.  We propose to evaluate the integrity performance of optimal LEO-GNSS PNT algorithms in specific transportation operations, including port and connected vehicle operations.  LEO satellites are more powerful, but their scope of application, for example in high-multipath environments between truck trailers and containers, has yet to be determined.  We will evaluate the LEO-based PNT coverage in multi-layered maps.  These maps will display suggested routes with maximal PNT integrity, will account for building signal obstructions, and will dynamically change with LEO satellite motion. 

US DOT Priorities:  This research project directly targets the US DOT’s research priority area of Reducing Transportation Cybersecurity Risks.  GNSS augmentation using other radio-frequency PNT solutions can help ensure resilience to jamming and spoofing attacks.  We will be investigating LEO/GNSS integration methods and will be quantifying their integrity and continuity to establish multi-layered R-PNT performance maps for multi-modal surface transportation applications.   

We will develop the tools and methods to rigorously quantify LEO-based PNT performance.  Transferring cutting-edge LEO-based PNT technology into practice for transportation modernization requires mediation between the US DOT and industry agents. We will leverage our experience acting as neutral mediators in this research program. 

Outputs:  In this jumpstart project, we will develop and provide: 

  • High-integrity LEO satellite measurement error models in high-multipath surface environments leveraging probabilistic methods, such as overbounding theory used in aviation. 

  • Risk-minimizing algorithms that best utilize LEO signals in surface vehicle applications. 

  • Performance maps quantifying the integrity and continuity of LEO-based PNT augmentation in port operations and connected vehicle applications and facilitate the development of performance standards. 

We expect interest in this research from LEO satellite constellation service providers and from LEO and GNSS signal simulator and receiver manufacturers.  

Outcomes/Impacts:  As a complement or as an alternative to GNSS, LEO satellite ranging signals can provide robust, secure, global, R-PNT solutions.  The aim of this project is to quantify the PNT performance of this emerging technology for surface transportation applications.  It will provide guidance and motivation for further LEO-based technology development and will bring scrutiny to LEO satellite performance.  The results of this project will be shared with the DOT, GNSS researchers, industry, and standardization bodies.  

Final Research Report:  (Upon completion of the project we will provide a link to the final report.)  

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