The proliferation of GNSS jamming and spoofing in certain parts of the world have accelerated the search for alternative positioning technologies. Satellite navigation experts advocate for a "system of systems" approach, where GNSS remains the backbone, augmented by Low Earth Orbit (LEO) layer for complementarity and global coverage, terrestrial 5G networks layer for regional coverage and indoor users, and user equipment sensors like Inertial Measurement Units (IMUs). This thesis investigates two innovative positioning techniques within this evolving landscape, focusing on leveraging 5G networks and LEO-PNT layers to supplement GNSS technologies. For 5G, a Synchronization Signal Block (SSB)-based positioning method designed to operate seamlessly on existing 5G infrastructure is proposed. Rigorous field testing has demonstrated the feasibility of the concept and its ability to meet emergency call requirements (50 m horizontal positioning accuracy) and even get close to the 10 meters target of 5G Positioning Service Level 1. To achieve this performance level the UE’s positioning engine need to effectively detect and reject outliers, given the noisy nature of SSB-based pseudoranges. The thesis also provides practical implementation insights, offering a comprehensive blueprint for network operators to roll out this positioning service in their system. The second positioning technology investigated is LEO-PNT. This concept consists in a complementary LEO orbit satellite layer to augment and backup GNSS. Analysis of its standalone performance, as well as its integration with the proposed 5G SSB positioning and GNSS have been investigated in depth, in particular in conditions emulating obstructed environments. Code-based synthetic LEO-PNT observations were fused with real 5G and GNSS pseudoranges in an Extended Kalman Filter (EKF). LEO-PNT standalone and LEO-PNT fused with GNSS achieved sub-meter horizontal positioning accuracy at the 68th percentile and within 3 meters at the 95th percentile in the emulated obstructed environment.
La proliferazione di GNSS jamming e spoofing in alcuni posti ha accelerato la ricerca di tecnologie di posizionamento alternative. Gli esperti di navigazione satellitare propongono un approccio integrato, in cui il GNSS rimane la infrastruttura fondamentale, potenziato da satelliti in orbita bassa (LEO) per complementarietà e copertura globale, da una rete 5G terrestre per la copertura regionale, e da sensori disponibility nel mobile. Questa tesi esamina due tecniche di posizionamento innovative all’interno di questo panorama in evoluzione, concentrandosi sullo sfruttamento delle reti 5G e delle costellazioni LEO-PNT. Per il 5G, viene proposto un metodo di posizionamento basato su Synchronization Signal Block (SSB) progettato per funzionare senza problemi sull’infrastruttura 5G esistente. Rigorosi test sul campo hanno dimostrato la fattibilita del concetto e la sua capacita di soddisfare il requisiti delle chiamate di emergenza (precision di posizionamento 2D di 50 metri). Per raggiungere questo livello, il motore di posizionamento dell’UE deve eliminare efficacemente le osservazioni anomale, data la natura rumorosa degli pseudorange basati su SSB. La tesi fornisce anche approfondimenti pratici sull’implementatzione, offrendo un imagine completa per gli operatori di rete 5G per attivare questo servizio nel loro sistema. La seconda tecnica si concentra su LEO-PNT, offrendo un livello complementare basato su satelliti per aumentare e supportare GNSS. Una simulazione approfondita delle sue prestazioni autonome, nonché la sua integrazione con il metodo basato su 5G proposto, esplora il potenziale dei sistemi ibridi per migliorare la precisione e l’affidabilità del posizionamento, in particolare in ambienti urbani e ostruiti. Gli pseudorange LEO-PNT sintetici sono stati integrati a pseudorange 5G e GNSS reali ed elaborati utilizzando un Extended Kalman Filter (EKF). I risultati evidenziano una precisione sub-metrica in configurazioni ibride e una significativa resilienza in scenari ostruiti.
Modern positioning systems: exploring 5G and LEO-PNT as complements to GNSS
Grec, Florin-Catalin
2024/2025
Abstract
The proliferation of GNSS jamming and spoofing in certain parts of the world have accelerated the search for alternative positioning technologies. Satellite navigation experts advocate for a "system of systems" approach, where GNSS remains the backbone, augmented by Low Earth Orbit (LEO) layer for complementarity and global coverage, terrestrial 5G networks layer for regional coverage and indoor users, and user equipment sensors like Inertial Measurement Units (IMUs). This thesis investigates two innovative positioning techniques within this evolving landscape, focusing on leveraging 5G networks and LEO-PNT layers to supplement GNSS technologies. For 5G, a Synchronization Signal Block (SSB)-based positioning method designed to operate seamlessly on existing 5G infrastructure is proposed. Rigorous field testing has demonstrated the feasibility of the concept and its ability to meet emergency call requirements (50 m horizontal positioning accuracy) and even get close to the 10 meters target of 5G Positioning Service Level 1. To achieve this performance level the UE’s positioning engine need to effectively detect and reject outliers, given the noisy nature of SSB-based pseudoranges. The thesis also provides practical implementation insights, offering a comprehensive blueprint for network operators to roll out this positioning service in their system. The second positioning technology investigated is LEO-PNT. This concept consists in a complementary LEO orbit satellite layer to augment and backup GNSS. Analysis of its standalone performance, as well as its integration with the proposed 5G SSB positioning and GNSS have been investigated in depth, in particular in conditions emulating obstructed environments. Code-based synthetic LEO-PNT observations were fused with real 5G and GNSS pseudoranges in an Extended Kalman Filter (EKF). LEO-PNT standalone and LEO-PNT fused with GNSS achieved sub-meter horizontal positioning accuracy at the 68th percentile and within 3 meters at the 95th percentile in the emulated obstructed environment.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/241302