This newly revised and greatly expanded edition of the popular Artech House book Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems offers you a current and comprehensive understanding of satellite navigation, inertial navigation, terrestrial radio navigation, dead reckoning, and environmental feature matching . It provides both an introduction to navigation systems and an in-depth treatment of INS/GNSS and multisensor integration. The second edition offers a wealth of added and updated material, including a brand new chapter on the principles of radio positioning and a chapter devoted to important applications in the field. Other updates include expanded treatments of map matching, image-based navigation, attitude determination, acoustic positioning, pedestrian navigation, advanced GNSS techniques, and several terrestrial and short-range radio positioning technologies. The book shows you how satellite, inertial, and other navigation technologies work, and focuses on processing chains and error sources. In addition, you get a clear introduction to coordinate frames, multi-frame kinematics, Earth models, gravity, Kalman filtering, and nonlinear filtering. Providing solutions to common integration problems, the book describes and compares different integration architectures, and explains how to model different error sources. You get a broad and penetrating overview of current technology and are brought up to speed with the latest developments in the field, including context-dependent and cooperative positioning. DVD Included: Features eleven appendices, interactive worked examples, basic GNSS and INS MATLAB simulation software, and problems and exercises to help you master the material.

Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems, Second Edition

An increasing number of wireless applications rely on GPS signals for localization, navigation, and time synchronization. However, civilian GPS signals are known to be susceptible to spoofing attacks which make GPS receivers in range believe that they reside at locations different than their real physical locations. In this paper, we investigate the requirements for successful GPS spoofing attacks on individuals and groups of victims with civilian or military GPS receivers. In particular, we are interested in identifying from which locations and with which precision the attacker needs to generate its signals in order to successfully spoof the receivers. We will show, for example, that any number of receivers can easily be spoofed to one arbitrary location; however, the attacker is restricted to only few transmission locations when spoofing a group of receivers while preserving their constellation. In addition, we investigate the practical aspects of a satellite-lock takeover, in which a victim receives spoofed signals after first being locked on to legitimate GPS signals. Using a civilian GPS signal generator, we perform a set of experiments and find the minimal precision of the attacker's spoofing signals required for covert satellite-lock takeover.

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On the requirements for successful GPS spoofing attacks

This article is a survey on communication aspects of High Altitude Platforms (HAPs), namely airships or aircraft positioned in the stratosphere between 17 and 22 km. HAPs can be considered as a novel solution for providing telecommunications services. This survey begins with an introduction to HAPs, that is, some historical information and advantages of HAPs compared to terrestrial and satellite networks, followed by information about suitable airships and aircraft, frequency bands allocated to HAPs, possible architectures, and some points on the system structure. We continue with the studies that have been carried out on channel modeling and interference, antennas, transmission and coding techniques. We also refer to access and resource allocation techniques that have been performed so far. Finally, the survey concludes with the types of applications that HAPs are suitable for, in addition to some related projects.

Broadband communications via high-altitude platforms: a survey

Many operations in power grids, such as fault detection and event location estimation, depend on precise timing information. In this paper, a novel Time Synchronization Attack (TSA) is proposed to attack the timing information in smart grid. Since many applications in smart grid utilize synchronous measurements and most of the measurement devices are equipped with global positioning system (GPS) for precise timing, it is highly probable to attack the measurement system by spoofing the GPS. The effectiveness of TSA is demonstrated for three applications of phasor measurement unit (PMU) in smart grid, namely transmission line fault detection, voltage stability monitoring and event locationing. The validity of TSA is demonstrated by numerical simulations.

Time Synchronization Attack in Smart Grid: Impact and Analysis

Accurately determining one's position has been a recurrent problem in history [1]. It even precedes the first deep-sea navigation attempts of ancient civilizations and reaches the present time with the issue of legal mandates for the location identification of emergency calls in cellular networks and the emergence of location-based services. The science and technology for positioning and navigation has experienced a dramatic evolution [2]. The observation of celestial bodies for navigation purposes has been replaced today by the use of electromagnetic waveforms emitted from reference sources [3].

Challenges in Indoor Global Navigation Satellite Systems: Unveiling its core features in signal processing

In this paper, the problem of acquiring the pilot and data channel of the next-generation systems (as Galileo, and GPS modernization) is addressed and analyzed, focusing the majority of the attention to the problem of managing the higher sign reversal transition rate due to the navigation message in the data channel and to the secondary code in the pilot channel. It must be considered that in the case of the Galileo E1 signals, each period of the spreading sequence may suffer of a sign change which can reduce the correlation gain. Moreover, the sign transition occurred on the block of samples being processed produces a correlation peak splitting along the Doppler axis of the search space matrix constructed during the acquisition phase and this may lead to a wrong Doppler estimate. Here, we propose an acquisition detection methodology in order to cope with the aforementioned impairments. The main idea behind the proposed algorithm derives by the fact that even though a sign transition occurs, the total useful signal energy remains unchanged, so it is possible to process the search space in order to recover in a nonambiguous way not only the presence of a satellite but also the correct spreading code delay phase and its Doppler shift. The effectiveness of the proposed method will be deeply assessed with a simulation campaign in terms of detection and false detection rate, which will be presented by means of the so-called receiver operative characteristic curves and compared with the state-of-the-art acquisition methodologies.

GNSS Signal Acquisition in the Presence of Sign Transition

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 lock loop (DLL) and the amplitude lock loop (ALL) are two basic elements in the structure. DLL is in charge of estimating and tracking the code delay of a specific ray in the incoming signal while ALL is in charge of estimating the corresponding amplitude. A pair of DLL and ALL makes a Unit, devoted to track LOS or a multipath signal. Several Units are incorporated in the CADLL structure, and then able to track the different component rays from the overall incoming signal. The feedback architecture and special working strategy of CADLL boost the performances of the parameter estimation accuracy, the noise tolerance ability and the error mitigation for short-range multipath.

Turbo architecture for multipath mitigation in global navigation satellite system receivers

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 the results of preliminary tests performed in lab on low cost GNSS receivers under spoofing attack Such tests have been performed at the Istituto Superiore Mario Boella (ISMB) research institute and at the European Commission Joint Research Centre (EC-JRC) with the final goal of identifying effective countermeasures to increase receivers robustness

Performance assessment of low cost GPS receivers under civilian spoofing attacks

The work presented in this paper introduces an innovative architecture for the tracking loop within the Galileo receiver (i.e. an innovative Delay Lock Loop (DLL)) which has been patented by the authors [1]. Such an innovative strategy has been especially tailored for the alignment of a Binary Offset Carrier (n.n) (BOC) modulated signal. It is in fact well known that BOC(1,1) has been chosen as the format of the Signal-In-Space (SIS) broadcast by the novel European satellite navigation system Galileo for the Open Access Service (OAS) over the L1 carrier frequency [2]. The innovative internal architecture here proposed is able to exploit all the features of the BOC(1,1) signal reducing the overall complexity of the required hardware and software blocks. Such an architecture applies to all BOC(n.n) possible signals

A Novel Algorithm for the Code Tracking of BOC [n,n] Modulated Signals

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 relevant effects in term of measurement errors on the code tracking, its consequences on the carrier tracking can not be neglected in high accuracy applications that rely on the carrier phase measurement such as, for example, real time kinematics (RTK) survey. Particular attention is addressed to the multiplexed binary offset carrier (MBOC) signals and the alternate BOC (AltBOC) signals. The investigation is conducted considering a two ray model with the aim of producing an error diagram showing the multipath effect in the carrier tracking: the delay locked loop (DLL) PLL interaction is considered in a static - low dynamic environment. Closed loop simulations are conducted by means of specific software tools based on the GNSS fully software receiver developed by the NavSAS group. Performance verification is done for a noisy environment. Results show loops performance in a multipath affected environment and the effects of noise in the carrier tracking operations. The PLL performance evaluation under multipath conditions, considering as input MBOC and AltBOC modulated signals, is important to understand the behavior of the new modulations especially in case of carrier tracking based applications that are the more demanding in terms of final positioning performance (i.e. geodetic applications).

Paolo Mulassano

Papers

GNSS Signal Acquisition in the Presence of Sign Transition

Turbo architecture for multipath mitigation in global navigation satellite system receivers

Performance assessment of low cost GPS receivers under civilian spoofing attacks

A Novel Algorithm for the Code Tracking of BOC [n,n] Modulated Signals

Performance analysis of MBOC, AltBOC and BOC modulations in terms of multipath effects on the carrier tracking loop within GNSS receivers