Implementation of Moving-Base-GNSS en NAVKA Multisensor GNSS / MEMS /optics navigation algorithms and systems

[EN] Implementation of Moving-Base-GNSS in NAVKA Multisensor GNSS / MEMS / Optics Navigation Algorithms and Systems. Development and implementation of an ambiguity resolution algorithm related to the Moving-Base-GNSS situation. Algorithm implementation in the RTKLIB open source library (C / C ++). Development of software that allows to calculate the position of a rover from the coordinates of a master receiver (DGNSS / PPP) and from the baselines calculated with the algorithm in question.[ES] Implementation of Moving-Base-GNSS in NAVKA Multisensor GNSS/MEMS/Optics Navigation Algorithms and Systems. Desarrollo e implementación de un algoritmo de resolución de ambigüedades relacionado con la situación Moving-Base-GNSS. Implementación del algoritmo en la librería de código abierto RTKLIB (C/C++). Desarrollo de un software que permite calcular la posición de un rover a partir de las coordenadas de un receptor máster (DGNSS/PPP) y de las líneas base calculadas con el algoritmo en cuestión.Hernández Olcina, J. (2019). Implementation of Moving-Base-GNSS en NAVKA Multisensor GNSS / MEMS /optics navigation algorithms and systems. http://hdl.handle.net/10251/139434TFG

Global ionospheric maps : estimation and assessment in post-processing and real-time

The research of this paper-based dissertation is focused on Global Ionospheric Maps (GIM) generation and assessment. In summary, the novelty and thematic unity in this works relies on four different but complementary topics: 1. Defining a systematic procedure to validate and quantify the quality of GIMs based on independent data sources or techniques. 2. Applying this methodology to not only the GIMs computed at UPC, but also to most of the currently open accessible GIMs inside the scientific community. 3.Including newly available Global Navigation Satellite Systems (GNSS) data to the processing of UPC's GIMs. 4. Assessment and distribution also of real-time GIMs. More in detail, my first contribution has been to the definition of a complete GIM validation procedure. This procedure is based on two methods: direct VTEC (Vertical Total Electron Content) altimeter and GNSS difference of slant TEC (Total Electron Content), both of them giving complementary information of the GIM performance. The main advantage of using satellite altimeter data is the fact that we are using a truly independent information source with regard to the input data used for GIM generation. This allows assessing the TEC from a entirely different point-of-view, fully different and independent to any error that may affect GNSS systems and its processing. The second technique, relies on using the same type of input data but in this case from permanent GNSS stations not participating in the GIM generation. The main advantages of this second technique is twofold: first, it allows to asses the GIMs on land; and second its a low latency direct assessment of the GIM, given a more direct information about the processing and interpolation done with the GNSS input data. Afterwards, a second contribution has been to use the previously defined methodology to validate all the GIMs generated by the International GNSS Service (IGS) Associated Analysis Centers (IAAC), and some other candidates to join them, for a more than a full solar cycle (starting from end of 2001 to beginning of 2017). As a side result, it is also demonstrated that while the time interval of the GIM has little influence on its overall quality, the interpolation technique used by the IAACs has an important role. Finally, this work also lead to the acceptance of the previously mentioned IAAC candidates since it demonstrated the good quality of their GIMs. Another contribution has been, as part of the European GRC project, improving the currently in production UPC's TOMION (TOMographic IONospheric) software used to generate the UQRG (UPC's rapid GIM) map. The software input source data was restricted to GPS L1 and L2. Now it allows processing all current frequencies available for GPS, Galileo and Beidou. This software has been internally tested for some specific days with the previously explained altimeter method giving results with improved quality for specific combinations of GNSS systems and frequencies. Using this work flow but focused on single frequency processing, a last article was published analysing the ionospheric footprint of the solar eclipse over North America during 2017. Finally, another contribution has been to improve the data acquisition and distribution system for the real-time GIM generation processing chain. Furthermore, as part of UPC contribution to the Real Time Ionospheric Monitoring Working Group (RTIM-WG) of the International Association of Geodesy (IAG) and following the previously explained methodology, an assessment of the GIMs generated by the members of this sub-commission have been performed. As a result of all these efforts, UPC has been leading inside the IGS frame, and made a first implementation, of a new real-time combined map.La recerca realitzada en aquesta tesis en format compendi d’articles esta enfocada en la generació i validació de mapes ionosfèrics globals (GIM, del angles Global Ionospheric Maps). En resum, la novetat i unitat temàtica d’aquesta tesis esta basada en quatre temes diferents però complementaris: • Definició d’un procediment sistemàtic per validar i quantificar la qualitat dels GIMs basada en fonts de dades o tècniques independents. • Aplicar aquesta metodologia no nomes als GIMs generats a UPC, sinó també a la resta de GIMs d’accés obert actualment existent dintre la comunitat científica internacional. • Incloure en el processat per generar els GIMs de UPC dades de les noves constel·lacions GNSS (del angles Global Navigation Satellite Systems) disponibles. • Validació i distribució també dels GIMs en temps real. Com a conseqüència, també s’ha aconseguit generar un primer GIM combinat en temps real. Mes en detall, la meva primera contribució va ser definir un procediment complet de validació de GIM. Aquest procediment esta basat en dos mètodes: obtenció directa del contingut vertical total d’electrons (VTEC, del angles, Vertical Total Electron Content) a partir de dades d’altimetria i per diferencies del contingut total d’electrons (TEC, del angles Total Electron Content) inclinat de dades GNSS. Els dos donen informació complementaria de la qualitat dels GIM. L’avantatge principal d’utilitzar dades de satèl·lits altimètrics es que es una font de dades completament diferent de les que s’utilitzen per la generació dels GIMs. Aquest fet ens permet verificar el TEC des d’una perspectiva diferent, plenament independent de qualsevol font d’error que pugui afectar al propi sistema GNSS o el seu processat. El segon mètode, es basa en la mateix tipus de dades que s’utilitzen pel càlcul dels GIM però en aquest cas amb dades d’estacions permanent GNSS no involucrades en la generació dels GIMs a avaluar. L’avantatge principal d’aquest segon mètodes es doble: primer, permet avaluar el GIM sobre els continents; i segon, permet fer la anàlisis directa de baixa latència del GIM, a mes a mes donant informació directa sobre el processat i la interpolació aplicada sobre les dades GNSS. Seguidament, la meva segona contribució va ser utilitzar la metodologia prèviament definida per validar tots els GIM generats per part dels centres d’anàlisis associats al Servei Internacional de GNSS (IGS, del angles International GNSS Service) i altres centres candidats a unir-se a IGS, per mes d’un cicle solar (des de finals del 2001 fins al inici del 2017). Com a resultat secundari, també va permetre demostrar que per una banda l’interval temporal dels GIM te poca influencia sobre la seva qualitat global, però per altra banda la tècnica d’interpolació emprada per part dels centres te un impacte molt important. Finalment, aquest article va portar a l’admissió d’aquests candidats prèviament mencionats a centres d’anàlisis associats a IGS donat que es va demostrar la bona qualitat dels seus GIMs. Una altra contribució important va ser, com a part del projecte europeu GRC, millorar el software TOMION (TOMographic IONospheric) de UPC, actualment en producció generant el GIM UQRG (GIM ràpid de UPC). Aquest software nomes permetia utilitzar dades de GPS L1 i L2. Les millores realitzades durant aquesta tesis permeten processar totes les freqüències actualment existent de GPS, Galileo i Beidou. El software ha estat internament validat per certs dies específics amb el mètode explicat prèviament d’altimetria millorant els resultats en comparació a la versió anterior per certes combinacions de constel·lacions GNSS i freqüències. Utilitzant aquesta nova metodologia de processat aplicada a una sola freqüència, un últim article va ser publicat analitzant l’empremta ionosfèrica de l’eclipsi solar sobre Amèrica del nord durant el 2017. Finalment, una altre contribució va ser millorar el mètode d’adquisició i distribució del sistema de processat del GIM en temps real. Es mes, com a part de la contribució de la UPC, es va realitzar una validació dels GIMs generats pels participants del grup de treball de monitorització en temps real de la ionosfera (RTIM-WG, del angles Real Time Ionospheric Monitoring Working Group) de l’Associació Internacional de Geodèsia (IAG, del angles International Association of Geodesy) seguint la metodologia anteriorment citada. Com a resultat d’aquestes tasques la UPC ha liderat i mplementat un nou mapa combinat en temps real, en el marc de IGS.Postprint (published version

Global ionospheric maps : estimation and assessment in post-processing and real-time

The research of this paper-based dissertation is focused on Global Ionospheric Maps (GIM) generation and assessment. In summary, the novelty and thematic unity in this works relies on four different but complementary topics: 1. Defining a systematic procedure to validate and quantify the quality of GIMs based on independent data sources or techniques. 2. Applying this methodology to not only the GIMs computed at UPC, but also to most of the currently open accessible GIMs inside the scientific community. 3.Including newly available Global Navigation Satellite Systems (GNSS) data to the processing of UPC's GIMs. 4. Assessment and distribution also of real-time GIMs. More in detail, my first contribution has been to the definition of a complete GIM validation procedure. This procedure is based on two methods: direct VTEC (Vertical Total Electron Content) altimeter and GNSS difference of slant TEC (Total Electron Content), both of them giving complementary information of the GIM performance. The main advantage of using satellite altimeter data is the fact that we are using a truly independent information source with regard to the input data used for GIM generation. This allows assessing the TEC from a entirely different point-of-view, fully different and independent to any error that may affect GNSS systems and its processing. The second technique, relies on using the same type of input data but in this case from permanent GNSS stations not participating in the GIM generation. The main advantages of this second technique is twofold: first, it allows to asses the GIMs on land; and second its a low latency direct assessment of the GIM, given a more direct information about the processing and interpolation done with the GNSS input data. Afterwards, a second contribution has been to use the previously defined methodology to validate all the GIMs generated by the International GNSS Service (IGS) Associated Analysis Centers (IAAC), and some other candidates to join them, for a more than a full solar cycle (starting from end of 2001 to beginning of 2017). As a side result, it is also demonstrated that while the time interval of the GIM has little influence on its overall quality, the interpolation technique used by the IAACs has an important role. Finally, this work also lead to the acceptance of the previously mentioned IAAC candidates since it demonstrated the good quality of their GIMs. Another contribution has been, as part of the European GRC project, improving the currently in production UPC's TOMION (TOMographic IONospheric) software used to generate the UQRG (UPC's rapid GIM) map. The software input source data was restricted to GPS L1 and L2. Now it allows processing all current frequencies available for GPS, Galileo and Beidou. This software has been internally tested for some specific days with the previously explained altimeter method giving results with improved quality for specific combinations of GNSS systems and frequencies. Using this work flow but focused on single frequency processing, a last article was published analysing the ionospheric footprint of the solar eclipse over North America during 2017. Finally, another contribution has been to improve the data acquisition and distribution system for the real-time GIM generation processing chain. Furthermore, as part of UPC contribution to the Real Time Ionospheric Monitoring Working Group (RTIM-WG) of the International Association of Geodesy (IAG) and following the previously explained methodology, an assessment of the GIMs generated by the members of this sub-commission have been performed. As a result of all these efforts, UPC has been leading inside the IGS frame, and made a first implementation, of a new real-time combined map.La recerca realitzada en aquesta tesis en format compendi d’articles esta enfocada en la generació i validació de mapes ionosfèrics globals (GIM, del angles Global Ionospheric Maps). En resum, la novetat i unitat temàtica d’aquesta tesis esta basada en quatre temes diferents però complementaris: • Definició d’un procediment sistemàtic per validar i quantificar la qualitat dels GIMs basada en fonts de dades o tècniques independents. • Aplicar aquesta metodologia no nomes als GIMs generats a UPC, sinó també a la resta de GIMs d’accés obert actualment existent dintre la comunitat científica internacional. • Incloure en el processat per generar els GIMs de UPC dades de les noves constel·lacions GNSS (del angles Global Navigation Satellite Systems) disponibles. • Validació i distribució també dels GIMs en temps real. Com a conseqüència, també s’ha aconseguit generar un primer GIM combinat en temps real. Mes en detall, la meva primera contribució va ser definir un procediment complet de validació de GIM. Aquest procediment esta basat en dos mètodes: obtenció directa del contingut vertical total d’electrons (VTEC, del angles, Vertical Total Electron Content) a partir de dades d’altimetria i per diferencies del contingut total d’electrons (TEC, del angles Total Electron Content) inclinat de dades GNSS. Els dos donen informació complementaria de la qualitat dels GIM. L’avantatge principal d’utilitzar dades de satèl·lits altimètrics es que es una font de dades completament diferent de les que s’utilitzen per la generació dels GIMs. Aquest fet ens permet verificar el TEC des d’una perspectiva diferent, plenament independent de qualsevol font d’error que pugui afectar al propi sistema GNSS o el seu processat. El segon mètode, es basa en la mateix tipus de dades que s’utilitzen pel càlcul dels GIM però en aquest cas amb dades d’estacions permanent GNSS no involucrades en la generació dels GIMs a avaluar. L’avantatge principal d’aquest segon mètodes es doble: primer, permet avaluar el GIM sobre els continents; i segon, permet fer la anàlisis directa de baixa latència del GIM, a mes a mes donant informació directa sobre el processat i la interpolació aplicada sobre les dades GNSS. Seguidament, la meva segona contribució va ser utilitzar la metodologia prèviament definida per validar tots els GIM generats per part dels centres d’anàlisis associats al Servei Internacional de GNSS (IGS, del angles International GNSS Service) i altres centres candidats a unir-se a IGS, per mes d’un cicle solar (des de finals del 2001 fins al inici del 2017). Com a resultat secundari, també va permetre demostrar que per una banda l’interval temporal dels GIM te poca influencia sobre la seva qualitat global, però per altra banda la tècnica d’interpolació emprada per part dels centres te un impacte molt important. Finalment, aquest article va portar a l’admissió d’aquests candidats prèviament mencionats a centres d’anàlisis associats a IGS donat que es va demostrar la bona qualitat dels seus GIMs. Una altra contribució important va ser, com a part del projecte europeu GRC, millorar el software TOMION (TOMographic IONospheric) de UPC, actualment en producció generant el GIM UQRG (GIM ràpid de UPC). Aquest software nomes permetia utilitzar dades de GPS L1 i L2. Les millores realitzades durant aquesta tesis permeten processar totes les freqüències actualment existent de GPS, Galileo i Beidou. El software ha estat internament validat per certs dies específics amb el mètode explicat prèviament d’altimetria millorant els resultats en comparació a la versió anterior per certes combinacions de constel·lacions GNSS i freqüències. Utilitzant aquesta nova metodologia de processat aplicada a una sola freqüència, un últim article va ser publicat analitzant l’empremta ionosfèrica de l’eclipsi solar sobre Amèrica del nord durant el 2017. Finalment, una altre contribució va ser millorar el mètode d’adquisició i distribució del sistema de processat del GIM en temps real. Es mes, com a part de la contribució de la UPC, es va realitzar una validació dels GIMs generats pels participants del grup de treball de monitorització en temps real de la ionosfera (RTIM-WG, del angles Real Time Ionospheric Monitoring Working Group) de l’Associació Internacional de Geodèsia (IAG, del angles International Association of Geodesy) seguint la metodologia anteriorment citada. Com a resultat d’aquestes tasques la UPC ha liderat i mplementat un nou mapa combinat en temps real, en el marc de IGS.Postprint (published version

Ambiguity resolution of single frequency GPS measurements

This thesis considers the design of an autonomous ride-on lawnmower, with particular attention paid to the problem of single frequency Global Navigation Satellite System (GNSS) ambiguity resolution. An overall design is proposed for the modification of an existing ride-on lawnmower for autonomous operation. Ways of sensing obstacles and the vehicle's position are compared. The system's computer-to-vehicle interface, software architecture, path planning and control algorithms are all described. An overview of satellite navigation systems is presented, and it is shown that existing high precision single frequency GNSS receivers often require time-consuming initialisation periods to perform ambiguity resolution. The impact of prior knowledge of the topography is analysed. A new algorithm is proposed, to deal with the situation where different areas of the map have been mapped at different levels of precision. Stationary and kinematic tests with real-world data demonstrate that when the map is sufficiently precise, substantial improvements in initialisation time are possible. Another algorithm is proposed, using a noise-detecting acceptance test taking data from multiple receivers on the same vehicle (a GNSS com- pass configuration). This allows a more demanding threshold to be used when noise levels are high, and a less demanding threshold to be used at other times. Tests of this algorithm reveal only slight performance improvements. A final algorithm is proposed, using Monte Carlo simulation to account for time-correlated noise during ambiguity resolution. The method allows a fixed failure rate configuration with variable time, meaning no ambiguities are left floating. Substantial improvements in initialisation time are demonstrated. The overall performance of the integrated system is summarised, conclusions are drawn, further work is proposed, and limitations of the techniques and tests performed are identified

Robust GNSS Carrier Phase-based Position and Attitude Estimation Theory and Applications

Mención Internacional en el título de doctorNavigation information is an essential element for the functioning of robotic platforms and intelligent transportation systems. Among the existing technologies, Global Navigation Satellite Systems (GNSS) have established as the cornerstone for outdoor navigation, allowing for all-weather, all-time positioning and timing at a worldwide scale. GNSS is the generic term for referring to a constellation of satellites which transmit radio signals used primarily for ranging information. Therefore, the successful operation and deployment of prospective autonomous systems is subject to our capabilities to support GNSS in the provision of robust and precise navigational estimates. GNSS signals enable two types of ranging observations: –code pseudorange, which is a measure of the time difference between the signal’s emission and reception at the satellite and receiver, respectively, scaled by the speed of light; –carrier phase pseudorange, which measures the beat of the carrier signal and the number of accumulated full carrier cycles. While code pseudoranges provides an unambiguous measure of the distance between satellites and receiver, with a dm-level precision when disregarding atmospheric delays and clock offsets, carrier phase measurements present a much higher precision, at the cost of being ambiguous by an unknown number of integer cycles, commonly denoted as ambiguities. Thus, the maximum potential of GNSS, in terms of navigational precision, can be reach by the use of carrier phase observations which, in turn, lead to complicated estimation problems. This thesis deals with the estimation theory behind the provision of carrier phase-based precise navigation for vehicles traversing scenarios with harsh signal propagation conditions. Contributions to such a broad topic are made in three directions. First, the ultimate positioning performance is addressed, by proposing lower bounds on the signal processing realized at the receiver level and for the mixed real- and integer-valued problem related to carrier phase-based positioning. Second, multi-antenna configurations are considered for the computation of a vehicle’s orientation, introducing a new model for the joint position and attitude estimation problems and proposing new deterministic and recursive estimators based on Lie Theory. Finally, the framework of robust statistics is explored to propose new solutions to code- and carrier phase-based navigation, able to deal with outlying impulsive noises.La información de navegación es un elemental fundamental para el funcionamiento de sistemas de transporte inteligentes y plataformas robóticas. Entre las tecnologías existentes, los Sistemas Globales de Navegación por Satélite (GNSS) se han consolidado como la piedra angular para la navegación en exteriores, dando acceso a localización y sincronización temporal a una escala global, irrespectivamente de la condición meteorológica. GNSS es el término genérico que define una constelación de satélites que transmiten señales de radio, usadas primordinalmente para proporcionar información de distancia. Por lo tanto, la operatibilidad y funcionamiento de los futuros sistemas autónomos pende de nuestra capacidad para explotar GNSS y estimar soluciones de navegación robustas y precisas. Las señales GNSS permiten dos tipos de observaciones de alcance: –pseudorangos de código, que miden el tiempo transcurrido entre la emisión de las señales en los satélites y su acquisición en la tierra por parte de un receptor; –pseudorangos de fase de portadora, que miden la fase de la onda sinusoide que portan dichas señales y el número acumulado de ciclos completos. Los pseudorangos de código proporcionan una medida inequívoca de la distancia entre los satélites y el receptor, con una precisión de decímetros cuando no se tienen en cuenta los retrasos atmosféricos y los desfases del reloj. En contraposición, las observaciones de la portadora son super precisas, alcanzando el milímetro de exactidud, a expensas de ser ambiguas por un número entero y desconocido de ciclos. Por ende, el alcanzar la máxima precisión con GNSS queda condicionado al uso de las medidas de fase de la portadora, lo cual implica unos problemas de estimación de elevada complejidad. Esta tesis versa sobre la teoría de estimación relacionada con la provisión de navegación precisa basada en la fase de la portadora, especialmente para vehículos que transitan escenarios donde las señales no se propagan fácilmente, como es el caso de las ciudades. Para ello, primero se aborda la máxima efectividad del problema de localización, proponiendo cotas inferiores para el procesamiento de la señal en el receptor y para el problema de estimación mixto (es decir, cuando las incógnitas pertenecen al espacio de números reales y enteros). En segundo lugar, se consideran las configuraciones multiantena para el cálculo de la orientación de un vehículo, presentando un nuevo modelo para la estimación conjunta de posición y rumbo, y proponiendo estimadores deterministas y recursivos basados en la teoría de Lie. Por último, se explora el marco de la estadística robusta para proporcionar nuevas soluciones de navegación precisa, capaces de hacer frente a los ruidos atípicos.Programa de Doctorado en Ciencia y Tecnología Informática por la Universidad Carlos III de MadridPresidente: José Manuel Molina López.- Secretario: Giorgi Gabriele.- Vocal: Fabio Dovi

BDS GNSS for Earth Observation

For millennia, human communities have wondered about the possibility of observing phenomena in their surroundings, and in particular those affecting the Earth on which they live. More generally, it can be conceptually defined as Earth observation (EO) and is the collection of information about the biological, chemical and physical systems of planet Earth. It can be undertaken through sensors in direct contact with the ground or airborne platforms (such as weather balloons and stations) or remote-sensing technologies. However, the definition of EO has only become significant in the last 50 years, since it has been possible to send artificial satellites out of Earth’s orbit. Referring strictly to civil applications, satellites of this type were initially designed to provide satellite images; later, their purpose expanded to include the study of information on land characteristics, growing vegetation, crops, and environmental pollution. The data collected are used for several purposes, including the identification of natural resources and the production of accurate cartography. Satellite observations can cover the land, the atmosphere, and the oceans. Remote-sensing satellites may be equipped with passive instrumentation such as infrared or cameras for imaging the visible or active instrumentation such as radar. Generally, such satellites are non-geostationary satellites, i.e., they move at a certain speed along orbits inclined with respect to the Earth’s equatorial plane, often in polar orbit, at low or medium altitude, Low Earth Orbit (LEO) and Medium Earth Orbit (MEO), thus covering the entire Earth’s surface in a certain scan time (properly called ’temporal resolution’), i.e., in a certain number of orbits around the Earth. The first remote-sensing satellites were the American NASA/USGS Landsat Program; subsequently, the European: ENVISAT (ENVironmental SATellite), ERS (European Remote-Sensing satellite), RapidEye, the French SPOT (Satellite Pour l’Observation de laTerre), and the Canadian RADARSAT satellites were launched. The IKONOS, QuickBird, and GeoEye-1 satellites were dedicated to cartography. The WorldView-1 and WorldView-2 satellites and the COSMO-SkyMed system are more recent. The latest generation are the low payloads called Small Satellites, e.g., the Chinese BuFeng-1 and Fengyun-3 series. Also, Global Navigation Satellite Systems (GNSSs) have captured the attention of researchers worldwide for a multitude of Earth monitoring and exploration applications. On the other hand, over the past 40 years, GNSSs have become an essential part of many human activities. As is widely noted, there are currently four fully operational GNSSs; two of these were developed for military purposes (American NAVstar GPS and Russian GLONASS), whilst two others were developed for civil purposes such as the Chinese BeiDou satellite navigation system (BDS) and the European Galileo. In addition, many other regional GNSSs, such as the South Korean Regional Positioning System (KPS), the Japanese quasi-zenital satellite system (QZSS), and the Indian Regional Navigation Satellite System (IRNSS/NavIC), will become available in the next few years, which will have enormous potential for scientific applications and geomatics professionals. In addition to their traditional role of providing global positioning, navigation, and timing (PNT) information, GNSS navigation signals are now being used in new and innovative ways. Across the globe, new fields of scientific study are opening up to examine how signals can provide information about the characteristics of the atmosphere and even the surfaces from which they are reflected before being collected by a receiver. EO researchers monitor global environmental systems using in situ and remote monitoring tools. Their findings provide tools to support decision makers in various areas of interest, from security to the natural environment. GNSS signals are considered an important new source of information because they are a free, real-time, and globally available resource for the EO community

Carrier-phase multipath in satellite-based positioning

[no abstract

Innovative Solutions for Navigation and Mission Management of Unmanned Aircraft Systems

The last decades have witnessed a significant increase in Unmanned Aircraft Systems (UAS) of all shapes and sizes. UAS are finding many new applications in supporting several human activities, offering solutions to many dirty, dull, and dangerous missions, carried out by military and civilian users. However, limited access to the airspace is the principal barrier to the realization of the full potential that can be derived from UAS capabilities. The aim of this thesis is to support the safe integration of UAS operations, taking into account both the user's requirements and flight regulations. The main technical and operational issues, considered among the principal inhibitors to the integration and wide-spread acceptance of UAS, are identified and two solutions for safe UAS operations are proposed: A. Improving navigation performance of UAS by exploiting low-cost sensors. To enhance the performance of the low-cost and light-weight integrated navigation system based on Global Navigation Satellite System (GNSS) and Micro Electro-Mechanical Systems (MEMS) inertial sensors, an efficient calibration method for MEMS inertial sensors is required. Two solutions are proposed: 1) The innovative Thermal Compensated Zero Velocity Update (TCZUPT) filter, which embeds the compensation of thermal effect on bias in the filter itself and uses Back-Propagation Neural Networks to build the calibration function. Experimental results show that the TCZUPT filter is faster than the traditional ZUPT filter in mapping significant bias variations and presents better performance in the overall testing period. Moreover, no calibration pre-processing stage is required to keep measurement drift under control, improving the accuracy, reliability, and maintainability of the processing software; 2) A redundant configuration of consumer grade inertial sensors to obtain a self-calibration of typical inertial sensors biases. The result is a significant reduction of uncertainty in attitude determination. In conclusion, both methods improve dead-reckoning performance for handling intermittent GNSS coverage. B. Proposing novel solutions for mission management to support the Unmanned Traffic Management (UTM) system in monitoring and coordinating the operations of a large number of UAS. Two solutions are proposed: 1) A trajectory prediction tool for small UAS, based on Learning Vector Quantization (LVQ) Neural Networks. By exploiting flight data collected when the UAS executes a pre-assigned flight path, the tool is able to predict the time taken to fly generic trajectory elements. Moreover, being self-adaptive in constructing a mathematical model, LVQ Neural Networks allow creating different models for the different UAS types in several environmental conditions; 2) A software tool aimed at supporting standardized procedures for decision-making process to identify UAS/payload configurations suitable for any type of mission that can be authorized standing flight regulations. The proposed methods improve the management and safe operation of large-scale UAS missions, speeding up the flight authorization process by the UTM system and supporting the increasing level of autonomy in UAS operations

A review of system integration and current integrity monitoring methods for positioning in intelligent transport systems

Applications of intelligent transportation systems are continuously increasing. Since positioning is a key component in these systems, it is essential to ensure its reliability and robustness, and monitor its integrity so that the required levels of positioning accuracy, integrity, continuity and availability can be maintained. In challenging environments, such as urban areas, a single navigation system is often difficult to fulfil the positioning requirements. Therefore, integrating different navigation sensors becomes intrinsic, which may include the global navigation satellite systems, the inertial navigation systems, the odometers and the light detection and ranging sensors. To bind the positioning errors within a pre-defined integrity risk, the integrity monitoring is an essential step in the positioning service, which needs to be fulfilled for integrated vehicular navigation systems used in intelligent transportation systems. Developing such innovative integrity monitoring techniques requires knowledge of many relevant aspects including the structure, positioning methodology and different errors affecting the positioning solution of the individual and integrated systems. Moreover, knowledge is needed for the current mitigation techniques of these errors, for possible fault detection and exclusion algorithms and for computation of protection levels. This paper provides an overview and discussion of these aspects with a focus on intelligent transportation systems

Kinematic State Estimation using Multiple DGPS/MEMS-IMU Sensors

Animals have evolved over billions of years and understanding these complex and intertwined systems have potential to advance the technology in the field of sports science, robotics and more. As such, a gait analysis using Motion Capture (MOCAP) technology is the subject of a number of research and development projects aimed at obtaining quantitative measurements. Existing MOCAP technology has limited the majority of studies to the analysis of the steady-state locomotion in a controlled (indoor) laboratory environment. MOCAP systems such as the optical, non-optical acoustic and non-optical magnetic MOCAP systems require predefined capture volume and controlled environmental conditions whilst the non-optical mechanical MOCAP system impedes the motion of the subject. Although the non-optical inertial MOCAP system allows MOCAP in an outdoor environment, it suffers from measurement noise and drift and lacks global trajectory information. The accuracy of these MOCAP systems are known to decrease during the tracking of the transient locomotion. Quantifying the manoeuvrability of animals in their natural habitat to answer the question “Why are animals so manoeuvrable?” remains a challenge. This research aims to develop an outdoor MOCAP system that will allow tracking of the steady-state as well as the transient locomotion of an animal in its natural habitat outside a controlled laboratory condition. A number of researchers have developed novel MOCAP systems with the same aim of creating an outdoor MOCAP system that is aimed at tracking the motion outside a controlled laboratory (indoor) environment with unlimited capture volume. These novel MOCAP systems are either not validated against the commercial MOCAP systems or do not have comparable sub-millimetre accuracy as the commercial MOCAP systems. The developed DGPS/MEMS-IMU multi-receiver fusion MOCAP system was assessed to have global trajectory accuracy of _0:0394m, relative limb position accuracy of _0:006497m. To conclude the research, several recommendations are made to improve the developed MOCAP system and to prepare for a field-testing with a wild animal from a family of a terrestrial megafauna