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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Two kinds of differential GPS (DGPS) technology on position differential GPS and pseudo-range differential GPS are studied and compared in this paper. Positioning tests by single GPS receiver, position DGPS and pseudo-range DGPS systems based on GPSOEM board are done. Experiment result indicates that position error is about 30 - 100 meters on single GPS receiver and position error is reduced to 3 - 10 meters on DGPS. Furthermore, Developed DGPS system which is based on GPS-OEM has the advantages of low cost, utility and flexibility, etc.

O objetivo deste trabalho é avaliar as variações espaço-temporais da dinâmica morfo-sedimentar do sistema praial de Ilha Comprida-SP. Assim, para reconhecer os padrões de onda encontrados na região, resultados do modelo global de ondas WAVEWATCH III foram utilizados. Da mesma forma, levantamentos de campo periódicos foram realizados em cinco diferentes setores com obtenção de dados morfológicos e sedimentares. Simulações com o modelo numérico MIKE21 SW foram realizadas para reconhecer as tendências de transporte e distribuição de força de onda. Os resultados mostraram uma tendência geral de transporte para NE, com maiores valores para a região sul em relação a norte, com dois setores principais de divergência residual: centro-sul e norte. A divergência centro-sul apresenta um aumento e uma migração para sul nos meses mais energéticos, enquanto que a divergência norte apresenta uma manutenção espacial ao longo das estações. A distribuição de força de onda mostrou-se mais elevada nos setores centro-sul e norte, coincidindo com os pontos de divergência. Dados granulométricos mostraram baixa variabilidade temporal, mas possuem diferenças espaciais que refletem a hidrodinâmica local. Os dados volumétricos apresentam maiores valores médios nos setores centro-norte e menores no centro-sul e norte. De modo geral, os resultados mostram que ao longo de uma linha de costa exposta a um mesmo padrão de ondas, sua variabilidade é um reflexo de alterações hidrodinâmicas locais. Tais conclusões são importantes para o conhecimento do estado atual das praias e de sua evolução. / The aim of this study is to evaluate the spatial-time variations on the beach system of Ilha Comprida-SP. Therefore, the wave reanalysis database from the global wave generation model WAVEWATCH III was used to recognize the wave pattern for the region. Furthermore, periodic field works at five different sectors have been conducted to collect morphological and sedimentological data. The numerical model MIKE 21 SW has been applied to propagate waves onshore and recognize the transport tendency and the nearshore wave power distribution. Results show a transport trend to the NE, with the southern sector being larger than the northern sector in magnitude, with two main residual longshore drift divergence spots: in the central-southern and northern regions. Moreover, the central-southern divergence spot become larger and migrated to the south during the most energetic months, while the northern divergence spot kept its position throughout the year. Wave power results show two main areas with higher values that coincide with the observed longshore divergence spots. Sediment data presents low temporal variability, although spatial variations have been found reflecting the hydrodynamic conditions. The volumetric data shows largest values in the central-northern sector, being smaller in the central-southern and northern regions. In summary, the findings show that along this wide open stretch of coastline, exposed to the same offshore wave regime, its variability is a result of local hydrodynamic conditions. These results help in further understanding the island\'s long term evolution and current state of its beaches.

The Global Positioning System (Navstar-GPS) has modernized and allow greater ease in surveys related to activities that require placement in real time. This system consists of a constellation of satellites around the Earth providing a service for 24 hours three-dimensional positioning, velocity and time information to the users. However, certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers. Thus, users can make more precise data collected with the Differential GPS (DGPS). It consists of a network of towers that receive the GPS signals and transmit the signals through fixed radio transmitters. It is effective to support activities which require continuous positioning in real time, which are required accuracies in the order of meters (1 to 3 m). In order for it be a medium to transmit the differential corrections, and the availability of this means there is not always easily and / or economic in Brazil, chose, for the development of this work, the RDS (Radio Data System) and NTRIP (Networked Transport of RTCM via Internet Protocol) for this purpose, using differential corrections transmitted by the format in its implementation DGPSBRDS simplified. It was analyzed statistically and compared it precision and accuracy or standard deviation or mean absolute deviation of the GPS positions with transmission of differential corrections in the RTCM (Radio Technical Commission for Maritime Services) with the surveys carried out by two systems: RDS and NTRIP. They also compared the methods of positioning, the absolute and differential. It was concluded that the differential positioning is obtained more satisfactory results with estimates of precision ranged from 1 to 3 m. The system met the goals of precision and accuracy was NTRIP, which has enabled coordinated in real time with greater accuracy. / O Sistema de Posicionamento Global (NAVSTAR-GPS) veio modernizar e permitir maior facilidade nos levantamentos relacionados às atividades que necessitam de posicionamento em tempo real. Este sistema é formado por uma constelação de satélites que envolvem a Terra fornecendo um serviço de posicionamento tridimensional durante 24 horas, informação de velocidade e tempo para seus utilizadores. Entretanto, certos fatores atmosféricos e outras fontes de erro podem afetar a precisão de receptores GPS. Desta forma, os usuários podem tornar os dados coletados mais precisos com o GPS Diferencial (DGPS). Ele consiste em uma rede de torres que recebem os sinais GPS e transmitem os sinais corrigidos por meio de transmissores de rádio. É eficaz para apoiar atividades nas quais se requer um posicionamento contínuo, em tempo real, onde são necessárias acurácias na ordem do metro (1 a 3 m). Tendo em vista que para ele é necessário um meio de comunicação para transmitir as correções diferenciais, e que a disponibilidade deste meio nem sempre existe de forma fácil e/ou econômica no Brasil, escolheu-se, para o desenvolvimento deste trabalho, o RDS (Radio Data System) e o NTRIP (Networked Transport of RTCM via Internet Protocol) para tal finalidade, utilizando correções diferenciais transmitidas por meio do formato DGPSBRDS em sua implementação simplificada. Analisou-se estatisticamente e comparou-se precisão ou desvio padrão e acurácia ou média dos desvios absolutos de posicionamentos GPS com transmissão de correções diferenciais no formato RTCM (Radio Technical Commission for Maritime Services) com os levantamentos efetuados pelos dois sistemas: RDS e NTRIP. Também foram comparados os modos de posicionamento, o absoluto e o diferencial. Concluiu-se que pelo posicionamento diferencial obtêm-se resultados mais satisfatórios cuja estimativa de precisão variou de 1 a 3 m. O sistema que satisfez os objetivos de precisão e acurácia foi o NTRIP, o qual permitiu obter coordenadas em tempo real com maior precisão.

O objetivo deste trabalho é avaliar as variações espaço-temporais da dinâmica morfo-sedimentar do sistema praial de Ilha Comprida-SP. Assim, para reconhecer os padrões de onda encontrados na região, resultados do modelo global de ondas WAVEWATCH III foram utilizados. Da mesma forma, levantamentos de campo periódicos foram realizados em cinco diferentes setores com obtenção de dados morfológicos e sedimentares. Simulações com o modelo numérico MIKE21 SW foram realizadas para reconhecer as tendências de transporte e distribuição de força de onda. Os resultados mostraram uma tendência geral de transporte para NE, com maiores valores para a região sul em relação a norte, com dois setores principais de divergência residual: centro-sul e norte. A divergência centro-sul apresenta um aumento e uma migração para sul nos meses mais energéticos, enquanto que a divergência norte apresenta uma manutenção espacial ao longo das estações. A distribuição de força de onda mostrou-se mais elevada nos setores centro-sul e norte, coincidindo com os pontos de divergência. Dados granulométricos mostraram baixa variabilidade temporal, mas possuem diferenças espaciais que refletem a hidrodinâmica local. Os dados volumétricos apresentam maiores valores médios nos setores centro-norte e menores no centro-sul e norte. De modo geral, os resultados mostram que ao longo de uma linha de costa exposta a um mesmo padrão de ondas, sua variabilidade é um reflexo de alterações hidrodinâmicas locais. Tais conclusões são importantes para o conhecimento do estado atual das praias e de sua evolução. / The aim of this study is to evaluate the spatial-time variations on the beach system of Ilha Comprida-SP. Therefore, the wave reanalysis database from the global wave generation model WAVEWATCH III was used to recognize the wave pattern for the region. Furthermore, periodic field works at five different sectors have been conducted to collect morphological and sedimentological data. The numerical model MIKE 21 SW has been applied to propagate waves onshore and recognize the transport tendency and the nearshore wave power distribution. Results show a transport trend to the NE, with the southern sector being larger than the northern sector in magnitude, with two main residual longshore drift divergence spots: in the central-southern and northern regions. Moreover, the central-southern divergence spot become larger and migrated to the south during the most energetic months, while the northern divergence spot kept its position throughout the year. Wave power results show two main areas with higher values that coincide with the observed longshore divergence spots. Sediment data presents low temporal variability, although spatial variations have been found reflecting the hydrodynamic conditions. The volumetric data shows largest values in the central-northern sector, being smaller in the central-southern and northern regions. In summary, the findings show that along this wide open stretch of coastline, exposed to the same offshore wave regime, its variability is a result of local hydrodynamic conditions. These results help in further understanding the island\'s long term evolution and current state of its beaches.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / With the rapid development of intelligent transport system in the world during the past few years, it promotes some navigation & location technology to a wide application especially in the car application. This paper firstly introduces some kinds of navigation & location systems and then analyzes the advantage and disadvantage of each system. On the basis of integrating every system and considering the high accuracy which can be achieved by adopting the technology based on DGPS (Differential Global Position System) at present, vehicle navigation & location system based on DGPS/INS/GIS integrated technology is put forward. The propound of this system shortens the distance between academic plan and real application greatly, and it provides a high accuracy and high reliability navigation & location system for traffic department and some car manufacturing Inc. In addition, this system is also provided with a friendly interface that makes it very easy to the manipulator or the user. The emphasis of this paper is put on the hardware and software of this system through introducing the system performance, the system component and the system software, and the characteristic of each module that makes up the whole system. The propound of the vehicle navigation & location system based on DGPS/INS/GIS integrated technology is a new attempt for development of intelligent transport system in our country, it will be sure to accelerate the process of our intelligent transport system.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / FAA is currently evaluating DGPS based CAT III Landing Systems for use as the next generation commercial aviation landing system standard. Any technique to validate such a DGPS based system must have at least equivalent accuracy. A laser position tracking system coupled with a high performance real-time computational capability was developed providing real-time analysis of performance. This real-time performance measurement system was key in enabling the quick completion of a large number of test approach and landings needed to achieve statistically accurate results.

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.

Scaled test-beds (STBs) are popular tools to develop and physically test algorithms for advanced driving systems, but often lack automotive-grade radars in their sensor suites. To overcome resolution issues when using a radar at small scale, a high-level sensor fusion approach between the radar and automotive-grade LiDAR was proposed. The sensor fusion approach was expected to leverage the higher spatial resolution of the LiDAR effectively. First, multi object radar tracking software (RTS) was developed to track a maneuvering full-scale vehicle using an extended Kalman filter (EKF) and the joint probabilistic data association (JPDA). Second, a 1/5th scaled vehicle performed the same vehicle maneuvers but scaled to approximately 1/5th the distance and speed. When taking the scaling factor into consideration, the RTS' positional error at small scale was, on average, over 5 times higher than in the full-scale trials. Third, LiDAR object sensor tracks were generated for the small-scale trials using a Velodyne PUCK LiDAR, a simplified point cloud clustering algorithm, and a second EKF implementation. Lastly, the radar sensor tracks and LiDAR sensor tracks served as inputs to a high-level track-to-track fuser for the small-scale trials. The fusion software used a third EKF implementation to track fused objects between both sensors and demonstrated a 30% increase in positional accuracy for a majority of the small-scale trials when compared to using just the radar or just the LiDAR to track the vehicle. The proposed track fuser could be used to increase the accuracy of RTS algorithms when operating in small scale and allow STBs to better incorporate automotive radars into their sensor suites. / Master of Science / Research and development platforms, often supported by robust prototypes, are essential for the development, testing, and validation of automated driving functions. Thousands of hours of safety and performance benchmarks must be met before any advanced driver assistance system (ADAS) is considered production-ready. However, full-scale testbeds are expensive to build, labor-intensive to design, and present inherent safety risks while testing. Scaled prototypes, developed to model system design and vehicle behavior in targeted driving scenarios, can minimize these risks and expenses. Scaled testbeds, more specifically, can improve the ease of safety testing future ADAS systems and help visualize test results and system limitations, better than software simulations, to audiences with varying technical backgrounds. However, these testbeds are not without limitation. Although small-scale vehicles may accommodate similar on-board systems to its full-scale counterparts, as the vehicle scales down the resolution from perception sensors decreases, especially from on board radars. With many automated driving functions relying on radar object detection, the scaled vehicle must host radar sensors that function appropriately at scale to support accurate vehicle and system behavior. However, traditional radar technology is known to have limitations when operating in small-scale environments. Sensor fusion, which is the process of merging data from multiple sensors, may offer a potential solution to this issue. Consequently, a sensor fusion approach is presented that augments the angular resolution of radar data in a scaled environment with a commercially available Light Detection and Ranging (LiDAR) system. With this approach, object tracking software designed to operate in full-scaled vehicles with radars can operate more accurately when used in a scaled environment. Using this improvement, small-scale system tests could confidently and quickly be used to identify safety concerns in ADAS functions, leading to a faster and safer product development cycle.

Differential corrections provide a method to improve the real-time accuracy and precision of GPS, but there are several sources of differential corrections and each have an associated accuracy and precision. In dynamic applications, the speed and heading of the rover may also have an effect on the accuracy and precision reported by the GPS receiver. These factors may have more of an effect on one differential correction method than another. An experiment was designed to test the differential correction methods under dynamic conditions. No corrections, OmniStar HP corrections, and RT2 corrections from a local base station were tested at several speeds and headings. The experiment was designed to determine what relationship, if any, exists between these factors and positional accuracy and precision of the differential correction sources. The results of the experiment will help designers choose the most effective solution for their positioning needs. The experiment showed that local RT2 corrections offered the most precision under dynamic conditions. The precision of OmniStar HP was close to that of RT2 corrections. The system with no corrections was the least precise of the three tested. The speed and direction of the vehicle were not observed to have a significant affect on the precision of the systems tested. The type of differential corrections used was not seen to have any influence on relative accuracy. The speed and direction of the vehicle did have an influence on the relative accuracy of the systems. / Master of Science