Marco Pini

Istituto Superiore Mario Boella (ISMB) | ISMB · Research Division of Navigation Technologies (NavSAS)

In recent years, the push for accurate and reliable time synchronization has gained momentum in critical infrastructures, especially in telecommunication networks, driven by the demands of 5G new radio and next-generation technologies that rely on submicrosecond timing accuracy for radio access network (RAN) nodes. Traditionally, atomic clocks pair...

The Public Observation (PO) test phase of the Galileo Open Service Navigation Message Authentication (OSNMA) signal is officially opened since November $15^{\text {th}}~2021$ , by the European Union Agency for the Space Programme (EUSPA). During this phase, any interested users is allowed to access the Signal in Space (SIS) for testing purposes,...

Adaptive notch filters (ANFs) have been widely investigated in literature for their low complexity and good performance, and used in many signal processing applications. More recently, they have been proven to be an effective solution against jamming interferences, considered more than ever a real threat to Global Navigation Satellite System signal...

Precision Agriculture (PA) refers to applications asking for reliable and highly available precise positions, at centimeter level, in most of operational scenarios. Machinery guidance, automatic steering and controlled traffic farming enable machinery to move along repeatable tracks on the field, minimizing pass-to-pass errors and overlaps. In the...

Signals from global navigation satellite systems (GNSS) can be utilized as signals of opportunity in remote sensing applications. Geophysical properties of the earth surface can be detected and monitored by processing the back-scattered GNSS signals from the ground. In the literature, several airborne GNSS-based passive radar experiments have been...

GNSS Reflectometry (GNSS-R) is a consolidated remote sensing technique that exploits the back-scattered GNSS signals to retrieve information about the Earth surface. By the use of GNSS-R sensors onboard UAVs, this tool can bring significant advantages in agriculture, especially for the detection of the presence of water/moisure in specific rural ar...

This chapter mainly focuses on the signal processing algorithms used in the physical layer of a global navigation satellite system (GNSS) receiver. It provides a general introduction of all the subsystems of a GNSS receiver. The chapter describes the first operation that a receiver performs when it is switched on: the acquisition of the satellites...

Many infrastructures that shape our lifestyle depend on the GPS. Even though not used for positioning, these infrastructures need GPS to derive a precise time synchronization necessary for their operations. Examples are power distribution grids, gateways for financial transactions, and telecommunication networks. However, GPS receivers, and more in...

Biomass is a spaceborn polarimetric P-band (435 MHz) synthetic aperture radar (SAR) in a dawn-dusk low Earth orbit. Its principal objective is to measure biomass content and change in all the Earth's forests. The ionosphere introduces the Faraday rotation on every pulse emitted by low-frequency SAR and scintillations when the pulse traverses a regi...

This chapter describes how an augmentation system can support a GNSS receiver of a vehicle (more in general a mobile object) in the PL evaluation. Since this approach has been firstly adopted in aviation, and it is already operative in some airports, we will describe a generic LAAS architecture, as a typical example of a GBAS, tailored to improve t...

This chapter reports fundamentals of the methods of the position computation based on global navigation satellite systems. In particular, it addresses the method of position computation based on the least square method and describes the errors which affect this type of position estimate.

During the last decade, the number of applications for land transportation that depend on systems for accurate positioning has significantly increased. Unfortunately, systems based on low cost Global Navigation Satellite System (GNSS) components harshly suffer signal impairments due to the environment surrounding the antenna, but new designs based...

In the modern automotive industry, the wide variety of Intelligent Transport System (ITS) services needs a positioning unit. The core of such unit is a Global Navigation Satellite System (GNSS) receiver hybridized or assisted by other sensors or data. In harsh environments, such as urban scenarios, the testing and performance assessment of these te...

The paper deals with the development of a Robust Position Unit (RPU) based on the real-time implementation of an advanced positioning algorithm. The RPU uses a tightly-coupled technique between a mass market single frequency GNSS chipset with a low cost Inertial Measurement Unit (IMU) based on Micro Electro-Mechanical Systems and an odometer. The t...

Global Navigation Satellite Systems (GNSSs) remain the principal mean of positioning in many applications and systems, but in several types of environment, the performance of standalone receivers is degraded. Although many works show the benefits of the integration between GNSS and Inertial Navigation Systems (INSs), tightly-coupled architectures a...

We investigate the geospace response to the 2015 St. Patrick's Day storm leveraging on instruments spread over South East Asia (SEA), covering a wide longitudinal sector of the low latitude ionosphere. A regional characterization of the storm is provided, identifying the peculiarities of ionospheric irregularities formation. The novelties of this w...

Nowadays more and more applications rely on the information provided by Global Navigation Satellite Systems (GNSSs), but the vulnerability of GNSS signals to interference, jamming and spoofing is a growing concern. Among all the possible sources of intentional interference, spoofing is extremely deceptive and sinister. In fact, the victim receiver...

Global Navigation Satellite Systems (GNSS) broadcast signals for positioning and navigation, which can be also employed for remote sensing applications. Indeed, the satellites of any GNSS can be seen as synchronized sources of electromagnetic radiation, and specific processing of the signals reflected back from the ground can be used to estimate th...

GINESTRA and ERICA are two projects funded in the framework of the ALCANTARA Initiative of the European Space Agency. GINESTRA is a survey aimed to explore the capabilities of ionosphere monitoring in South East Asia (SEA) and the Pacific region in order to identify institutions involved in this field and existing monitoring facilities which could...

Nowadays, Unmanned Aerial Vehicles (UAVs) platform are widely employed in a broad range of applications: from environmental monitoring and precise agriculture to humanitarian localization and rescue and prevention of events such as floods, fires, landslides. On the other hand, Global Navigation Satellite System Reflectometry (GNSS-R) is an emerging...

Reliable positioning and navigation is becoming imperative in more and more applications for public services, consumer products, and safety-critical purposes. Research for finding pervasive and robust positioning methodologies is critical for a growing amount of societal areas while making sure that navigation is trustworthy and the risks and threa...

Reliable positioning and navigation is becoming imperative in more and more applications for public services, consumer products, and safety-critical purposes. Research for finding pervasive and robust positioning methodologies is critical for a growing amount of societal areas while making sure that navigation is trustworthy and the risks and threa...

The GPS modernization program offers a new civil signal on the L2 band, which, together with the legacy L1 C/A signal, spurs the development of dual-frequency receivers for civil applications. This paper proposes a complete combined acquisition architecture dedicated to these receivers. The architecture fully utilizes the capacity of both signal ch...

The last decade has seen the success of satellite based navigation applications in the ordinary people’s life. New services with demanding performance are boosting also the development of improved technologies for navigation receivers. Although the navigation technology also rapidly evolved towards more complex signal processing techniques, when co...

This chapter deals with one of the major concerns for reliable use of Global Navigation Satellite Systems (GNSS), providing a description of intentional and unintentional threats, such as interference, jamming, and spoofing. Despite the fact that these phenomena have been studied since the early stages of Global Positioning System (GPS), they were...

In this paper the preliminary design of a Global Navigation Satellite System (GNSS) receiver with scatterometric capabilities is presented. The aim is to exploit the reflected GNSS signals to retrieve information about the soil characteristics. The receiver prototype is specifically designed to be small and lightweight, to be mounted on board an Un...

The Remote sensing group of Politecnico di Torino adapted a receiver developed by the Navigation Signal Analysis and Simulation group (NAVSAS) for positioning purposes, to be used for GNSS Reflectometry applications. Both direct and reflected GNSS signals were collected by this receiver mounted on an aircraft which flew over rice fields in the Verc...

GNSS Reflectometry is an emerging technique used for the remote sensing of soil surfaces. In this contribution an application of dielectric constant retrieval is presented. Both direct and reflected GPS signals were collected by a fully software receiver mounted on-board an aircraft. The reflected signal was processed with an open loop approach, ob...

GNSS Reflectometry is an emerging technique used for remote sensing of soil. Some measurements campaign for the characterization of soil moisture were performed considering a Software Defined Radio GPS receiver. Left Hand Circularly Polarized (LHCP) reflected signals were processed to extract Delay Doppler Maps (DDMs) and corresponding Delay Wavefo...

The disruptive effect of the interference in Global Navigation Satellite System (GNSS) receivers is well known. Jammers and spoofing attacks, in addition to time-varying environment effects, such as fading and multipath, can induce distortions on the correlation function resulting in a degraded positioning accuracy. Furthermore, improved performanc...

The extremely low power of Global Navigation Satellite System (GNSS) signals makes them vulnerable to disturbances and interference from external sources. These induce distortions on the correlation function that reflect upon a degraded pseudoranges measurement and poor positioning accuracy. On the other hand, the wide spread use of GNSS receivers...

Interference is an actual problem for Global Navigation Satellite System (GNSS) receivers. Despite a wide amount of research works available in literature, the growing risk represented by portable jamming devices indicates that interfering signals are still a concern for GNSS-based services. The design of simple detection methods, possibly applicab...

In the framework of the regional Italian project SMAT-F1, an experimental campaign using small aircraft flying an area above Vercelli (Piedmont, North Italy) was performed to remotely sense rice fields’ flooding state by applying Global Navigation Satellites System Reflectometry (GNSS-R) technique. Both direct and reflected GPS signals (the latest...

This paper gives a classification of intentional and unintentional threats, such as interference, jamming and spoofing, and discusses some of the recent trends concerning techniques for their detection and mitigation. Despite the fact that these phenomena have been studied since the early stages of Global Positioning System (GPS), they were mainly...

European Geostationary Navigation Overlay Service (EGNOS) is a satellite-based system developed to improve the performance of GPS in the European region. It not only enhances the estimated positioning accuracy but also provides an integrity solution. We assess the EGNOS performance through analysis of real measurements, performed in different road...

This chapter presents the results of a testing and validation activity carried out to analyze the performance of signal-processing techniques related to positioning and navigation. The steps included the setup of a measurement campaign and the setup of a shared database, the usage of this database to test algorithms, and the development of a softwa...

Recent improvements on receiver technologies, combined with the growth of new applications, increase the expectations for positioning and timing performance. New systems based on Global Navigation Satellite System (GNSS) are emerging, while safety and liability-critical applications relying on Global Positioning System (GPS) are becoming more popul...

This chapter presents the algorithms of digital signal processing implemented in the physical layer of global navigation satellite systems (GNSS) receivers. It starts with the analysis of the radio frequency (RF) signal received at the antenna and highlights the presence of a Doppler frequency shift. The chapter then illustrates the frequency down-...

In this study a new multipath mitigation architecture for satellite navigation receiver, named coupled amplitude delay lock loops (CADLLs) is presented. This architecture exploits the `turbo principle` to separately track the line-of-sight (LOS) signal and multipath signals in order to mitigate the effects of the multiple reflections. The delay loc...

In a GNSS receiver the measure of C/N₀ is not only supplementary information provided to the user together with the PVT (position, velocity, time), but it is also fundamental information to determine the status of the tracking subsystems and to control the receiver in critical environments. A classic approach to estimate the C/N<sub>0</s...

“Peers-based aiding GNSS” refers to collaborative systems composed by GNSS receivers that exchange aiding data in order to improve their performance. One of the main issues related to this type of systems is the time synchronization between receivers. The required precision of the synchronization depends on the type of data the receivers exchange....

Due to the large amount of different new applications based on GNSS systems, the issue of interference monitoring is becoming an increasing concern in the satellite navigation community. Threats for GNSS can be classified as unintentional interference, jamming and spoofing. Among them, spoofing is more deceitful because the target receiver might no...

Services based on Global Navigation Satellite Systems (GNSS) are currently in use in many critical networked infrastructures and crucial applications. Within the described scenario, the importance for the GNSS community of investigating the effects of spoofing attacks, together with anti-spoofing techniques, appears essential. This paper describes...

This paper presents the main features of NFUELS (FUll Educational Library of Signals for Navigation), a signal simulator designed to offer young researchers and students a complete, flexible and intuitive software tool able to offline reproduce and analyze GNSS signals as they appear at the Analog to Digital Converter output of a navigation receive...

In this paper a novel multipath mitigation architecture for satellite navigation receiver, named Coupled Amplitude Delay Lock Loops (CADLL) is presented. This architecture exploits the “turbo principle” to separately track the Line Of Sight (LOS) signal and multipath signals in order to mitigate the effects of the multiple reflections. The Delay Lo...

In the following lines we introduce a Software Defined Radio prototype terminal for Emergency Situations. More specifically this integrated terminal will have NAV/COM functions and so it will be composed by two modules: the Localization and Communication Components, running on the same machine and connected each other via TCP/IP protocol. The Local...

This paper proposes a new strategy for the acquisition of the GPS L5 signal. Although the L5 signal is mainly thought for aircraft navigation, it also will serve as a robust third signal for a broad range of GPS civil users. The GPS L5 signal features an enhanced signal structure, with two components, one with and one without a navigation message....

GPS modernization program offers a new civil signal on L2 band, which together with the legacy L1 C/A spurs the development of dual frequency receivers for civil applications. This paper proposes a complete combined acquisition architecture dedicated to these receivers. The architecture fully utilizes the capacity of both the signal channels as wel...

This paper describes an efficient algorithm, based on the gradient method, for the fine estimate of the Doppler shift of Global Navigation Satellite System (GNSS) signals. The algorithm is a suitable solution for software radio implementation, as it requires a moderate computational burden. The new approach is based on a close-form expression that...

In this paper we present a prototype of NAV/COM devices for emergency situations based on the software defined radio (SDR) technology. More specifically this integrated terminal will be composed of two modules, the localization and communication components, running on the same machine and connected each other via TCP/IP protocol. Both of them, then...

N-Gene is a GNSS receiver completely designed in software, able to run in real-time on a common Personal Computer. This kind of receiver implements the concept of Software Defined Radio (SDR) and can be used as a test-bed for the development of innovative algorithms and for their valida- tion in a real-time environment. This paper presents the so-...

The growth of new location-based applications, the improvements in receiver technologies, as well as the availability of new Global Navigation Satellite System (GNSS) signals, increase the expectations for positioning and timing performance. Recent applications foresee the use of commercial Global Positioning System (GPS) receivers in challenging e...

In a global navigation satellite system (GGNS) receiver the acquisition algorithms as well as the signal tracking play an important role in the receiver functioning. When the receiver is implemented in software radio technology the demanding computational complexity becomes a critical issue as much as the algorithms performance and stability. This...

The high level of flexibility achievable with Software Defined Radio (SDR) technology generates interest in the industry of mass market receivers, but represents also a valuable tool for research-oriented analysis. This paper exploits this last aspect and demonstrates how it is possible to assess the performance of different digital estimators of C...

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The objective of the work is the evaluation of the impact of new modulation strategies foreseen for the galileo signal in space (SIS) on the carrier tracking operation within the global navigation satellite systems (GNSS) receiver (namely frequency locked loop (FLL)/phase locked loop (PLL)) in presence of multipath. Although multipath has more rele...

In this paper we have analyzed the normalization problem in the evaluation of the DLL discriminator function. We know that the parameter setting of the DLL elements is strictly related to the definition of the discriminator function. If this function becomes sensible to the prompt fluctuations, due to a degradation of its estimation, also the loop...

In a GNSS receiver the measure of the carrier to noise power density ratio (CNo) is not only a measure of the strength of the received signal, but is also used to determine the lock condition of the carrier and tracking loops and to control the channel scheduling. This paper investigates the possibility of implementing various low complexity C/No e...

A reconfigurable and simultaneous dual band Galileo/GPS front-end receiver has been realized on 0.13-mum RFCMOS technology. The front-end uses only one fixed frequency PLL and VCO on a superheterodyne architecture to down-convert two RF (radio frequency) signals into two IF (intermediate frequency) signals in the range of 50 MHz to 150 Mhz. L1 and...

Recent years have seen an exponential increase of DVD equipped and navigation assisted cars. Nowadays a car trip can be both entertaining for passengers and computer assisted for drivers. In a further integration of automotive and information technologies, cars will be able to communicate to each other and to the Internet supporting safety, infotai...

The mitigation of radio frequency interference (RFI) has a fundamental role in global navigation satellite system (GNSS) applications, especially when a high level of availability is required. Several electromagnetic sources, in fact, might degrade the performance of the global positioning system (GPS) and Galileo receivers, and their effects can b...

This paper presents the first results obtained processing the Signal-In-Space broadcast by the Galileo In — Orbit Validation Element A (GIOVE-A) satellite, the first experimental Galileo satellite. The paper analyzes both the acquisition and tracking phase of a Galileo software receiver able to process raw samples of the signal collected by means o...

Recent experiments have shown that a valuable way to monitor the quality of the signal broadcast by Global Navigation Satellite System (GNSS) satellites is to use a high gain antenna. Signal monitoring experiments are important to check the health of the electronic devices on board of the satellite just after the launch, but also to characterize th...

In this paper a detailed evaluation of the performance of the architecture named “Turbo Delay Lock Loop” (TurboDLL) is presented. Such an architecture has been introduced by the authors in [1], as an innovative solution for improving the performance of satellite navigation receivers in multipath affected scenarios. The relevant innovation resides i...

There are a number of different error sources, such as multipath and thermal noise, which corrupt satellite navigation waveforms from their theoretical structure. However, even under ideal conditions the broadcast signals have some degree of deformation as a result of the practical individual hardware implementation. For the most demanding users of...

: This paper investigates the effect of the sampling frequency on Global Navigation Satellite System (GNSS) receiver performance. Modern digital navigation receivers sample the analog signal at the output of the Intermediate Frequency (IF) filter and implement digital tracking loops. The synchronization of the incoming and local code, fundamental t...

The increased interest for the design of applications based on both navigation and communication systems, represents an important driver for the design and implementation of innovative receivers architectures. The realization of civil GPS applications, the advent of the European navigation system Galileo, and the integration of localization service...

Since the selective availability was turned off, one of the major error sources in GNSS user positioning is represented by the deleterious superimposition of the same signa-in-space due to obstruction and ground reflections (multipath). Such an error component is the most critical in case of urban (or indoor) navigation due to the high density of p...

The increasing use of satellite navigation systems in ordinary life application, is demanding more and more protection of the position information, in order to provide not only accurate solutions, but also reliable and "trustable" information. For this reason, new algorithms, strategies techniques are being investigated and designed, in order to pr...