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This chapter presents and discusses the fundamentals of ultra‐wideband (UWB) technology, the main issues and the methods of obtaining high‐resolution ranging and localization. It illustrates some results related to the passive localization of energy autonomous tags using the UWB backscatter principle. The chapter also illustrates an experimental case study where UWB technology has been used to track a mobile node in a typical indoor environment and tracking experimental results using a Bayesian filtering approach, with a PF implementation. It further exploits prior knowledge from the mobility and perception models. After the FCC allowed the use of UWB signals in the USA, considerable amount of effort was put into the development and standardization of UWB systems. This effort resulted in the publication of the IEEE 802.15.4a standard in 2007 (IEE 2007) as a physical layer (PHY) alternative based on UWB to the IEEE 802.15.4 standard.

Cooperative mobile positioning is becoming increasingly important as a promising new branch of wireless location in which several research directions are being explored (e.g., positioning, tracking, data fusion and clustering). This chapter first discusses the framework of cooperative mobile positioning framework and then introduces the COMET as an innovative solution for position determination in fourth generation (4G) wireless networks. It also presents a brief survey of cooperative localization in robot networks and wireless sensor networks (WSNs), and examines the cooperative mobile positioning approach and its overall benefits. The chapter further illustrates the data fusion and filtering techniques, which have been adapted to cope with the cooperative framework. Finally, it describes COMET, an example of a cooperative augmentation system (CAS) in a cellular network, with its system architecture and its data fusion methods; and explores its performance, which has been evaluated via computer simulations.

This chapter begins by presenting the Location Stack, a framework created by Jeffrey Hightower, which offers an overview of an exemplary localization system with all its elements and interrelations, similar to the seven‐layer ISO/OSI model used in the field of communication systems. It introduces the first application area of positioning and thereby the formal definitions of a location‐based service (LBS), which is basically considered as the intersection of new information and communication technologies (NICTs), the Internet and geographic information systems (GISs). The chapter illustrates the "LBS ecosystem", which is an efficient parallel taken from biology, to show the many actors rotating around this business; in particular, these actors will be split into operational and non‐operational actors. It then presents taxonomies of LBSs, which are divided into the service model, application, market segment and content. The chapter focuses on the second of these classes and explains some application categories within LBSs.

This chapter presents two major approaches of data fusion: the least squares (LS) approach and the Bayesian framework. The LS approach is an algorithm that estimates the position of a mobile station (MS) by minimizing the squared error between the actual measurements observed in the wireless channel and the expected measurements resulting from the estimated position. In the Bayesian framework, the position is determined as an estimator that minimizes the mean square error between the actual measurements and the expected measurements. The chapter also provides three major implementations of the Bayesian framework: the Kalman filter (KF), the particle filter (PF) and grid‐based methods. The KF is a group of methods that assumes the measurements to be corrupted by white Gaussian noise, the PF is a Monte Carlo type of algorithm that does not constrain the noise component of the Gaussian distribution, and the grid‐based methods assume that the state space is discrete and finite.

We present experimental evaluations of human-induced perturbations on received-signal-strength-(RSS-) based ranging measurements for cooperative mobile positioning. To the best of our knowledge, this work is the first attempt to gain insight and understand the impact of both body loss and hand grip on the RSS for enhancing proximity measurements among neighbouring devices in cooperative scenarios. Our main contribution is represented by experimental investigations. Analysis of the errors introduced in the distance estimation using path-loss-based methods has been carried out. Moreover, the exploitation of human-induced perturbations for enhancing the final positioning accuracy through cooperative schemes has been assessed. It has been proved that the effect of cooperation is very limited if human factors are not taken into account when performing experimental activities.

It is well known property of the GNSS systems that they are able to deliver very precise Position, Velocity and Time information to the user. In this paper we introduce a GNSS receiver architecture, which is able to synchronize its operations to the GNSS signals it processes, be it live satellite signals or simulator signals, without the need of external synchronization equipment. This capability is useful for testing the receiver with GNSS simulators, and can also be used for synchronizing a set of GNSS receivers. Since the architecture does not need any external synchronization signals, it is convenient to move the GNSS receiver between testing premises. Most commercially available GNSS simulators can output some format of scenario information, and this scenario information is by default bound to be ticked on exact full second intervals according to the simulator clock. Having a receiver capable of doing the synchronization to the same time allows the receiver output its own measurements at the same time instants, making the comparisons extremely useful.

The navigation software of a GNSS receiver is responsible for producing the final Position, Velocity and Time (PVT) solution. The receiver needs to acquire and track enough satellites to solve the unknown parameters, namely the x-, y-, and z- coordinates and time biases. In this chapter, we address the basic navigation software tasks, with emphasis on the issues which arise in a multi-system GNSS receiver. In particular single-frequency GPS/Galileo multisystem is selected as an example. Since these GNSS systems both have a different reference time, the chapter includes a section about synchronization to either GPS or Galileo time. Also, this chapter covers topics such as the pseudorange construction, the calculation of the satellite locations, the atmospheric corrections, the navigation solution and navigation data decoding in dual system receiver, and, finally, few words about the extra availability of satellites.

In this paper we present experimental evaluations of cooperative ranging-based approaches in mobile positioning. Our main contribution is represented by experimental investigations, analysis of the errors introduced in the distance estimation and exploitation of the knowledge of environmental perturbations with a NLLS algorithm, highlighting the limits of such cooperative schemes, proving that the effect of cooperation might be very limited in real-life scenarios.

New Global Navigation Satellite Systems like Galileo are expected to be fully operational in the future, thus increasing the availability of satellite signals for the GNSS receiver. As modern receivers have the capability of tracking different signals simultaneously, in this paper we evaluate how much stress all the available satellite signals will put on the processor responsible for calculating the PVT solution. We present C-language fixed-point method which does not require floating point support from the target processor, resulting in a target processor independent source code. The performance of the presented algorithms is shown in terms of clock cycles. In the end we demonstrate that it is possible to maintain a traditional 1Hz update rate on the processor even with high amount of satellites included into the navigation solution.

This paper deals with the propagation channel challenges affecting indoor positioning. Several methods are reviewed and experimental results are provided, showing that the pathloss method is preferable with respect to fingerprinting because of its intrinsic complexity and uncertain effective reliability under real-world conditions. Moreover the influence of the user and the heterogeneity of the devices pose a high challenge on the positioning accuracy.

In this paper we present a practical approach to relative positioning of heterogeneous mass market devices. We propose a user-centric solution exploiting measurements from on-the-fly fixed reference points detected during scanning procedures. The technique implemented on mobile devices is able to locate neighboring nodes, demonstrating to be a feasible and practical solution for sensing spatial social contexts in ad-hoc environments.

In this paper we present the effect of the hand-grip and the presence of the human body on received signal strength measurements when performing positioning of mass market devices in indoor environments. We demonstrate that the mitigation of both human body and hand-grip influence can enhance the positioning accuracy and that the human factor cannot be neglected in experimental activities with real mobile devices.

Mobile and wireless communications are global phenomena of large social ­relevance. During the last decades we have observed a constant increase of mobile subscribers worldwide, where, thanks to globalization and huge demands, the costs have decreased so much that the mobile phone has become a device affordable by almost everybody. In particular, mobile and wireless communication systems have opened up new scenarios for developing countries, which have finally the possibility to have global access from remote areas at low costs, much lower than when deploying wired systems. At the same time, we have experienced a metamorphosis of the mobile phone with respect to the services it provides to its users and its social relevance; indeed, from being a device merely used for voice calls and SMSs, it is now used for exchanging e-mails, taking pictures, retrieving location-based information, etc. Practically, it has turned into an advanced social-networking tool, which is nowadays exploited for enlarging one’s social sphere. Along with this change of skin there have been increasing research and ­development efforts at a global scale for mobile phones and mobile and wireless communications, in general. At the present time, we are actually heading to the fourth generation (4G), where the main drivers are higher data rates and the convergence among the several technologies available today. In this chapter, we exploit the second track in order to develop a localization solution that will provide 4G and beyond users more advanced services, like indoor navigation and cooperative location-based services.

In this paper we describe the prototype concept of multi-constellation GNSS receivers investigated in the Galileo Ready Advanced Mass Marker Receiver (GRAMMAR) EU FP7 project [1]. The purpose of our work is to provide technology solutions with their implementations for multi-system GNSS mass market receivers by motivating the need for both hardware and software research and present the functional blocks for a multi-constellation GNSS receiver.

Recently a lot of research has been going on in the field of Global Navigation Satellite System receivers. Only few projects have been providing open source hardware receivers. In this paper we present a university based GNSS receiver intended for open source release. The highly modular design of the receiver is described in detail. We also provide description of the software parts and advanced user interface of the receiver. In the end of the paper a test scenario is provided proving the functionality of the receiver design. The presented GNSS receiver architecture is expected to be valuable prototype for research purposes.

In this paper we propose a Collaborative Mapping (CM) method based on the exploitation of the WLAN Received Signal Strength (RSS) measured from short-range ad-hoc links between neighboring devices. The estimated spatial proximity allows on-the-fly calibrations of heterogeneous clients for Location Fingerprinting (LF) applications. This method can avoid long time-consuming and battery-draining calibrations when implementing Fingerprinting Location applications running on heterogeneous mass market devices.

Recently, people are demanding more and more social, ubiquitous and cognitive features on their smart phones to enhance communication and interactions between users. Indoor relative positioning technology provides potential to develop such applications. Several of projects and products of positioning systems have been carried out with different positioning technologies through past few years to demonstrate their potential features and abilities. The object of this thesis is to study and develop a practical relative positioning solution based on received signal strength measurement for locating neighbouring mass market mobile devices using passive scanning. Thus, we have implemented a python application for Linux-based mobile devices to demonstrate features and solutions. The results of the proposed positioning technique show it is feasible for implementing a practical relative-positioning application. Experiments have been carried out successfully to demonstrate the positioning technique with up to five heterogeneous devices in short range. /Kir11