Investigation of interference detection, localization and classification techniques in GNSS frequency bands (in collaboration with THALES ALENIA SPACE)

Background

The capability of a Global Navigation Satellite System (GNSS) to provide the user with reliable Position, Velocity and Time (PVT) estimates is paramount for many applications. However, the final positioning performance and even the capability of the GNSS receiver to acquire and track the satellite signals could be affected by external interferences occurred in the same or contiguous frequency bands. The aforementioned interferences could be:

• Unintentional: an external source is transmitting a signal in the frequencies adjacent to GNSS bands; unintentional interference are also out-of-band emissions from other licensed RF transmitters located nearby the GNSS receiver antenna that overpower the receiver’s front-end band-pass filters. In these categories, it is possible to find personal electronic devices, ultra-wideband radar, television, VHF, etc.

• Intentional: these interferences usually belong to in-band interference category, and they are commonly referred to as jamming and spoofing.

Detecting, localizing and classifying these interference sources is crucial for maintaining the reliability and accuracy of GNSS systems, especially in critical applications like aviation, transportation, and navigation for defence and emergency services.

Objectives

The main objective of this study is to investigate and compare the main techniques for the detection, localization and classification of interferences in GNSS bands in order to be able to select techniques potentially suitable for space applications. The study should include the review of the literature and the implementation of a selected subset of algorithms for at least one of the aforementioned aspects (detection, localization, classification).

Tasks

The study should encompass the following steps:

· Critical Review of the state-of-the-art methods and technologies used for GNSS interference detection, localization and classification (at least one of them) – Input available will be provided by TAS-I

· Implementation of a selected subset of the studied techniques in Matlab/Python

· Experimentation on simulated and/or real dataset

· Analyses of the results

Preferred Academic Background

Telecommunication Engineering, Electronics Engineering, Information Technology Engineering

Expected competencies

Good knowledge of MatLab (or Python) programming, Good knowledge of Signal Theory and Signal Processing, Knowledge of GNSS principles and PVT estimation (preferred), Basic knowledge of Communication Systems (preferred)

This thesis investigates the integration of space-based and ground-based ADS-B systems, focusing on multilateration (MLAT) performance and the impact of self-interference. Hybrid surveillance architectures improve coverage, especially in remote areas, but introduce interference issues.

Here, self-interference refers to the high rate of ADS-B message reception (“fruit”) that saturates sensors and limits their effective coverage. A simulation framework is developed to model combined receiver networks and evaluate interference under different traffic conditions.

self-interference degrades MLAT accuracy, particularly in high-density airspace without proper coordination. The findings will support the development of more reliable and efficient integrated surveillance systems for modern air traffic management.

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Integrating Space-based and Ground based ADS-B multilateration: Evaluating the final system performance

This thesis investigates the integration of space-based and ground-based ADS-B systems for multilateration (MLAT), focusing on the evaluation of overall system performance. Hybrid surveillance architectures, combining terrestrial and satellite-based receivers, offer enhanced coverage, particularly in remote and oceanic regions where traditional ground infrastructure is limited.

A simulation framework is developed to model the integrated network of receivers and to assess system performance under varying traffic densities and operational configurations. Key metrics such as positioning accuracy, detection probability, coverage, and system robustness are analyzed to provide a comprehensive evaluation.

The findings will contribute to the design and optimization of next-generation air traffic surveillance systems, supporting more accurate, reliable, and efficient aircraft tracking in modern airspace environments.

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GNSS jamming and spoofing in LEO constellation: real attack, risk assessment and possibile mitigation

Global Navigation Satellite Systems (GNSS) are increasingly vulnerable to jamming and spoofing, posing significant risks to positioning, navigation, and timing (PNT) services. These threats are particularly relevant for emerging Low Earth Orbit (LEO) constellations, which aim to enhance or complement traditional GNSS. This thesis analyzes real-world GNSS interference scenarios and evaluates their impact on LEO-based systems.

A risk assessment framework is developed to quantify effects on system performance. The study also investigates mitigation strategies such as advanced signal processing, multi-constellation integration, and cooperative techniques enabled by inter-satellite links. The goal is to support the design of resilient LEO systems capable of operating in hostile signal environments.

LEO constellation for RF-spectrum monitoring and cyber-attack detection: system design and performance evaluation

This thesis investigates the design and performance of a Low Earth Orbit (LEO) satellite constellation for global RF-spectrum monitoring and cyber-attack detection. The increasing congestion of the RF spectrum and the growing threat of malicious activities such as jamming and spoofing require more advanced and scalable monitoring solutions beyond traditional ground-based systems.

The proposed work focuses on defining an optimal constellation architecture, modeling RF signal environments, and developing detection algorithms capable of identifying anomalous transmissions. A simulation framework will be implemented to evaluate key performance metrics, including coverage, detection accuracy, latency, and geolocation capability.

The study aims to provide design guidelines and performance insights for space-based RF monitoring systems, highlighting their potential role in enhancing the security and resilience of modern communication infrastructures.

LUGRE mission: evaluation of the LUGRE data

This thesis focuses on the analysis and evaluation of data collected during the LUGRE mission, with the objective of assessing system performance and validating key mission concepts. The study will examine the characteristics and quality of the acquired measurements, including signal integrity, positioning accuracy, and environmental effects impacting the data.

Particular attention will be given to the comparison between expected and observed performance, highlighting discrepancies and their possible causes. Data processing techniques and statistical analysis will be applied to extract meaningful insights and evaluate the reliability of the system under real operational conditions.

The outcomes of this work aim to provide a comprehensive assessment of the LUGRE mission results, contributing to the improvement of future GNSS-based space applications and experimental mission designs.

Past Thesis

2025

“Enhanced Lunar Navigation Using Surface Beacons: Performance Analysis and Evaluation.” , Candidate: Bardia Hassannejad, Supervisor: Mauro Leonardi , Oct 2025