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Research to improve performance in resonant MEMS sensors has concentrated on novel designs, fabrication techniques, actuation and sensing mechanisms, often based on macroscale designs and phenomena which have been studied extensively. This dissertation is about one such actuation mechanism, called parametric excitation, based on the phenomenon of parametric resonance, to enable performance improvement in an electrostatically actuated MEMS ring resonator modulation can be conveniently achieved using electrostatic actuation which is a widely preferred actuation mechanism for MEMS.

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In 1999 Europe, through the European Commission and the European Space Agency, began detailed definition of a second generation Global Navigation Satellite System (GNSS). This GNSS development programme, known as “Galileo”, was intended to both complement and compete against the existing US Global Positioning System (GPS). Unlike GPS, Galileo is intended to be privately financed, following the initial development investment from the EC and ESA, which implies that Galileo should provide some revenue-earning services. From its earliest inception, the basis of these services has been assumed to be through the provision of Signal Integrity through an Integrity Flag broadcast through the Galileo system– a service which GPS cannot provide without some external system augmentation. This thesis undertakes a critical evaluation of the value of this integrity system in Galileo. This thesis has two parts. The first demonstrates that the conditions required to attract adequate private finance to the Galileo programme are incompatible with the system architecture derived from the early Galileo system studies and taken forward into the system early deployment phase, which includes an Integrity system within Galileo. The second part of this thesis aims to demonstrate that receivers which can combine the signals from GPS and Galileo may offer a free Integrity service which meet the needs of the majority of users, possibly up to the standards required for aviation precision approach. A novel Receiver Autonomous Integrity Monitoring (RAIM) technique is described, using an Errors in Variables/Total Least Squares approach to the detection of inconsistencies in an over-determined set of GNSS signal measurements. The mathematical basis for this technique is presented, along with results which compare the simulated performance of receivers using this algorithm against the expected performance of Galileo’s internal integrity determination system.

The key aim of this research is to contribute to the development of a robust and reliable navigation system in order to support the positioning requirements of advanced transport telematics (ATT) services. This is achieved through the development of high integrity map matching algorithms. In the last two decades, satellite navigation technology, especially the Global Positioning System (GPS), has established itself as a major positioning technology for land vehicle navigation. Deduced Reckoning (DR) sensors, which consist of an odometer and a gyroscope, are commonly used to bridge any gaps in GPS positioning. However, DR sensor positioning errors can grow rapidly if not controlled by another sensor or system such as GPS. Digital road maps are used for spatial reference of the vehicle location via a process known as map matching. Map matching algorithms use inputs generated from positioning technologies and supplement this with data from a high resolution digital road network map to provide an enhanced positioning output. Existing map matching algorithms have weaknesses which decrease their capability to support many ATT services. Three high integrity map matching algorithms are developed in this research. They are the improved topological, probabilistic, and fuzzy logic map matching algorithms. These algorithms are successfully implemented, tested and validated using real field test data. A reference (truth) vehicle trajectory, as determined by high accuracy GPS carrier phase positioning, is used to validate the algorithms. The integrity (level of confidence) of the algorithms is analysed by taking into account the uncertainty associated with the map-matched location and the error sources associated with the navigation system and the digital map. The effects of navigation systems and digital map quality on the performance of map matching algorithms are also investigated for suburban and urban road networks. The results suggest that all three map matching algorithms developed in the course of this research have the potential to support the navigation function of a wide range of ATT services. However, of the three, the fuzzy logic map matching algorithm offers the highest performance, both in terms of link identification and location determination.

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