Design and evaluation of an integrated GPS/INS system for shallow-water AUV Navigation

The major problem addressed by this research is the large and/or expensive equipment required by a conventional navigation system to accurately determine the position of an Autonomous Underwater Vehicle (AUV) during all phases of an underwater search or mapping mission. The approach taken was to prototype an integrated navigation system which combines Global Positioning System (OPS) and Inertial Measurement Unit (IMU), waterspeed and heading information using Kalman filtering techniques. Actual implementation was preceded by a computer simulation to test where the unit would fit into a larger hardware and software hierarchy of an AUV. The system was then evaluated in experiments which began with land based cart tests and progressed to open water trials where the unit was placed in a towed body behind a boat and alternately submerged and surfaced to provide periodic OPS updates to the Inertial Navigation System (INS). Test results and qualitative error estimates indicate that submerged navigation accuracy comparable to that of differential OPS may be attainable for periods of 30 seconds or more with low cost components of a small physical size.http://archive.org/details/designndevaluati1094535102NANAU.S. Navy (U.S.N.) authors

A Service Oriented Architecture Approach for Global Positioning System Quality of Service Monitoring

This research focuses on the development of a Service Oriented Architecture (SOA) for monitoring the Global Positioning System (GPS) Standard Positioning Service (SPS) in near real time utilizing a Mobile Crowd Sensing (MCS) technique. A unique approach to developing the MCS SOA was developed that utilized both the Depart- ment of Defense Architecture Framework (DoDAF) and the SOA Modeling Language (SoaML) guidance. The combination of these two frameworks resulted in generation of all the architecture products required to evaluate the SOA through the use of Model Based System Engineering (MBSE) techniques. Ultimately this research provides a feasibility analysis for utilization of mobile distributed sensors to provide situational awareness of the GPS Quality of Service (QoS). First this research provides justification for development of a new monitoring architecture and defines the scope of the SOA. Then an exploration of current SOA, MBSE, and Geospatial System Information (GIS) research was conducted. Next a Discrete Event Simulation (DES) of the MCS participant interactions was developed and simulated within AGI\u27s Systems Toolkit. The architecture performance analysis was executed using a GIS software package known as ArcMap. Finally, this research concludes with a suitability analysis of the proposed architecture for detecting sources of GPS interference within an Area of Interest (AoI)

Emergency response, the built environment and GPS signal quality: simulation and analysis of urban canyons in Quebec City

L’objectif général de cette recherche est de synthétiser les informations disponibles sur le développement d’un système d’urgence 9-1-1 pour les téléphones cellulaires dans le contexte nord américain. L’objectif spécifique du projet est de proposer une méthodologie qui détermine les conditions moyennes d’obstruction causée par les bâtiments qui nuisent à la qualité de la réception de signal GPS. Un modèle statistique de la qualité de signal GPS basé sur une campagne de mesures de réception des signaux GPS dans les arrondissements à caractère urbain dans la Ville de Québec (Canada) est employé pour simuler l’effet d’obstruction. Ces mesures ont montré une variabilité spatiale de la qualité de signal selon les conditions locales d’obstruction des édifices sur la voûte céleste. Une augmentation du pourcentage de ciel obstrué (effet de masque) a entraîné une augmentation de la probabilité de perte de signal GPS. Des cartes continues de la probabilité de perte de signal GPS ont été créés pour des feuillets de la Base de données topographiques de Québec au 1 : 20 000 en employant la technique d’interpolation spatiale par la méthode de la distance inverse pondérée (DIP).The general objective of this investigation is to extract the most pertinent information currently available on developing an emergency 9-1-1 system for cellular phones in the North American context. The specific objective of this project is to propose a methodology for determining the average obstruction by buildings which affect GPS satellite signal quality. A statistical model of GPS signal quality based on a field measurement campaign in the urban districts of Quebec City (Canada) was used to simulate this phenomenon. The measurements demonstrated a spatial variation in signal quality according to the building obstruction over the local sky. An increase in the percent of obstructed sky led to an increase in the probability of losing GPS signal lock. Continuous maps of GPS signal loss probability were created for sheets of the Quebec topographic database at the 1:20,000 scale using the Inverse Distance Weighting technique of spatial interpolation (IDW)

Modeling biomass transport on single lane forest roads and monitoring GPS accuracy for vehicle tracking under different forest canopy conditions

The transportation of wood and biomass resources from landing and other collection locations to processing and distribution sites is a substantial cost within the wood supply chain. These high costs provide a basis for research aimed at improving biomass transportation planning decisions and potentially reducing biomass transportation costs. Chip vans have been identified to be the most cost-efficient mode of transporting biomass provided the roads are suitable for the trucks which are generally built for highway use. Research to develop chip van performance simulation models for travel time prediction could potentially reduce biomass transportation costs by improving transportation planning decisions. GPS technology has the ability to record information such as location (longitude, latitude and elevation), movement (speed, heading) and travel time which makes it an attractive tool for data collection to develop, test and validate vehicle simulation models. In spite of several studies investigating the accuracy and performance of GPS under different forest conditions, the reliability of GPS receiver measurements for moving vehicles under forest canopy and in mountainous terrain has not been examined. This dissertation includes two manuscripts. One manuscript presents a Chip Van Travel Time Prediction Simulation Model (CHIP-VAN) that was developed using data collected by GPS receivers to track and monitor chip vans. The vans were exclusively used for transporting chipped (ground) biomass from forest operation sites in western Oregon. The other manuscript examines the accuracy and reliability of GPS for vehicle tracking under different forest canopy conditions and mountainous terrain. The model, CHIP-VAN, is developed based on the maximum limiting speeds on each road segment as limited by road grade, stopping sight distance (SSD) and road alignment as well as modeling the driver's behavior as these road conditions change. A two pass simulation was used in the model; the first pass simulation calculates the maximum limiting speeds on each road segment and the second pass simulates the driver's behavior and calculates the travel time. To emulate the driver's behavior, four cases that determine whether a driver will accelerate, decelerate or continue at current speed, were developed. The model has been tested for validation using the data collected for the study. The validation tests suggest that the model is appropriate for predicting travel time for chip vans on single lane forest roads with acceptable accuracy. The findings in the second study demonstrate that the GPS tracking accuracy of vehicles on forested roads are clearly influenced by the composition of the surrounding canopy, with the strongest influence being from heavy forest canopy cover. Accuracy is generally improved in areas with less forest canopy. The study concludes that the consumer-grade GPS receiver measurements determined are acceptable for tracking and improving biomass transport from forest supply locations to distribution and processing centers. The analysis of the range of accuracies found for vehicles operating within heavy forest canopy cover demonstrates that the accuracies are probably acceptable for many forest transportation monitoring and planning applications, including the mapping of forest road locations and other forest transportation operations. It is expected that the CHIP-VAN model and GPS accuracy studies will aid forest transportation managers in decision making and transportation planning in biomass operations. Most importantly it is hoped that the results of this research will increase transportation management planning efficiency for biomass and lead to improved methods for developing biomass cost assessment