Geodesy and Geomatics Engineering Technical Reports

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A method for processing data from a regional continuous crustal deformation GPS monitoring network
A method for processing data from a regional continuous crustal deformation GPS monitoring network
This thesis focuses on improvement of methods for processing GPS data to detect regional crustal deformation signals of centimetre or even millimetre level, based on the DIfferential POsitioning Program (DIPOP) GPS software package. The experimental field is the Western Canada Deformation Array (WCDA), a regional continuous GPS tracker network for monitoring crustal deformation in western Canada. As part of the Canadian National Earthquake Hazards Program, WCDA was established by the Geological Survey Canada, Natural Resources Canada primarily for the study of the seismic hazard in this region. DIPOP is a development of the Department of Geodesy and Geomatics Engineering, University of New Brunswick. Since the birth of DIPOP 1.0 in 1985, DIPOP has been continuously upgraded with the advance of GPS and computer techniques, and is still under development. Since error correction models directly affect the quality of processing results, the models of the tide and residual atmospheric delay corrections have been tested with the longest baseline of the WCDA network. Also, a weeklong GPS data set from 7 WCDA baselines was processed to evaluate the performance of DIPOP. The solutions for both the height component and baseline length show daily repeatability better than 1 cm for baselines ranging from 254 to 672 km. Differences between the weekly solutions from DIPOP and the ITRF2000 solutions published by International Earth Rotation Service (IERS) are of the order of a few centimetres in the components of latitude, longitude, and height. In order to test the capability of DIPOP to extract deformation signals, a continuous 52-week data set from 3 selected WCDA baselines was processed. Annual movement rates for the components of latitude, longitude, and height were estimated by weighted least squares linear fitting and assessed by values of the coefficient of determination and the F-test. The daily time series of the position solutions at the 3 remote sites show movement rates of 0.4 - 1.4 cm per year and -7.8 - 2.6 mm per year in the horizontal and vertical components, respectively. By analyzing the processed results, potential error sources affecting the accuracy of the DIPOP solutions were assessed. It is suggested that the methods for estimating residual tropospheric delay and correcting receiver antenna phase center variation need to be improved; and reduction of multipath interference needs to be taken into consideration in data processing for high-precision positioning. Improvement of the technique for detecting and fixing cycle slips was also studied. A method of automatically detecting cycle slips was developed and implemented in the preprocessor PREDD of DIPOP. The new method shows better efficiency for data processing with DIPOP.
A methodology for raster to vector conversion of colour scanned maps
A methodology for raster to vector conversion of colour scanned maps
This thesis is an attempt to automate a portion of the paper map conversion process. This includes replacing the manual digitization process by computer assisted skeletonization of scanned paper maps. In colour scanned paper maps various features on the map can be distinguished based on their colour. This research work differs from the previous research in the way that it uses the Delaunay triangulation and the Voronoi diagram to extract skeletons that are guaranteed to be topologically correct. The features thus extracted as object centrelines can be stored as vector maps in a Geographic Information System after labelling and editing. Furthermore, map updates are important in any Geographic Information System. This research work can also be used for updates from sources that are either hardcopy maps or digital raster images. The extracted features need manual editing in order to be usable in a Geographic Information System. This involves manual gap filling and clutter removal. A prototype application that is developed as part of the research has been presented. This application requires a digital image as input and processes it to produce skeletons or boundaries of objects. This research work can be further extended by considering automated gap filling in the extracted features.
A neutral framework for modelling and analysing Aboriginal land tenure systems
A neutral framework for modelling and analysing Aboriginal land tenure systems
Land tenure and land administration are culture- laden areas, as can be seen in Canada, where Aboriginal land tenure and land administration systems are challenging the conventional theory of property rights and western models of land administration. There is a need to better understand land tenure if land administration, which is concerned with implementing land tenure policies, is to be re-designed and improved upon. This thesis is concerned with developing a framework to guide the analysis, modelling, design and implementation of land tenure reforms for Aboriginal communities. A problem highlighted by the cross-cultural land tenure literature is the inherently biased emphasis of current land administrations towards eurocentric concepts of land and land tenure. The primary objective of this research is to help alleviate this inequitable eurocentric bias by developing an ethnocentrically equitable or neutral analytical framework for analysing and designing proposed reforms of Aboriginal land tenure and land administration systems. The major conclusion of this research is that the research objective can be achieved by developing a neutral framework that incorporates the cultural worldviews, concepts, values and aspirations of the community, and rigorously analyses, models and compares the land tenure systems of the Aboriginal group. The neutral framework is developed by integrating concepts and approaches from anthropology, geomatics engineering and soft systems engineering. The neutral framework entails first using the comparative design criteria of worldviews, values, concepts, goals and institutions of members of a community. This allows the Aboriginal land tenure systems to be described and analysed from the cultural perspective of the subject Aboriginal group. Conceptual logical models are then developed from the issues identified in the initial cultural analysis, to enable comparisons to be made between each developed conceptual model and its relevant existing land tenure system or subsystem. The comparisons are then evaluated to identify reforms to be made to the existing land tenure systems that are systemically desirable and culturally feasible for the subject community. The neutral framework is tested by applying it to the Mi’kmaq of mainland Nova Scotia, an Aboriginal community in eastern Canada. Comparisons are also made with the Nisga’a and the Lheidli T’enneh communities in western Canada.
A new navigation filter
A new navigation filter
This dissertation describes a new self-learning navigation filter associated with probability space and non-Newtonian dynamics. This new filter relies basically on the information contained in measurements on the vehicle: position fixes, velocities and their error statistics. The basic idea behind this new navigation filter is twofold: (1) A cluster of the observed position fixes contains true kinematic information about the vehicle in motion, (2) A motion model of the vehicle associated with the error statistics of the position fixes should be able to get, to a large extent, the information out of the measurements for use. We base the new filter on an analogy. We consider the statistical confidence region of every position fix as “source" tending to “attract" the undetermined trajectory to pass through this region. With these position fixes and their error statistics, a virtual potential field is constructed in which an imaginary mass particle moves. To make the new filter flexible and responsive to a changing navigation environment, we leave some parameters free and let the filter determine their values, using a sequence of observations and the criterion of least squares of the observation errors. We show that the trajectory of the imaginary particle can well represent the real track of the vehicle. The new navigation filter has been tested with both simulated and real navigation data, as an estimator, predictor, smoother and blunder detector. Its ability to accept navigator's intervention has also been tested. Compared with the Kalman filter, the new filter requires the uncertainties of observations to be known only relatively (cofactor matrix) and is able to offer a better navigation when the vehicle is under dynamic maneuvers and the data rate is small, but with a slower processing speed.
A physically meaningful model of vertical crust movements in Canada using smooth piecewise algebraic approximation
A physically meaningful model of vertical crust movements in Canada using smooth piecewise algebraic approximation
Different kinds of analytical models of crustal deformation have both advantages and limitations, and are appropriate to different deformation patterns. However, in wide areas where multiple geophysical phenomenon are responsible for the deformation, such as in Canada, it would be a challenge to infer a physically meaningful model that accommodates different kinds of scattered geodetic data, while offering the optimum approximation to them. We develop an efficient method to automatically compute a smooth approximation of large functional scattered re-levelling data and historical tide gauge records given over Canada and northern US to thereby compile a unified map of Vertical Crustal Movements (VCM). The area of study is divided into patches and piecewise algebraic surfaces are fitted to 2D observation points and tilt between them, where constraints are enforced between the parameters of the surfaces. When the surfaces are fitted to the data, the set of constraints is imposed in such a way that rather than the surfaces being fitted sequentially, they are fitted simultaneously. The VCM model accomplished in this research is computationally demanding and numerically manageable. Enforcing the continuity and smoothness in the first derivatives throughout the surfaces, the VCM model highlights the long wavelength spatial variations of the crust in Canada, mainly due to Post Glacial Rebound (PGR). The rate of changes of orthometric height obtained from the map of VCM (H& ) is compared with the map of rate of gravity changes (ġ) in Canada (Pagiatakis and Salib, 2003). The PGR hinge line follows the same pattern in both maps and the close correlation between the map of VCM and ġ map is easily traceable and is in a fairly good agreement with theoretical model of Jachens (1978) in different areas. The VCM is also compared to geodetic height changes based on GPS solutions in Canadian Base Network (CBN) stations (Henton et al., 2006). This investigation shows disagreement with the GPS solution in Canadian prairies. In this study, some of theprobable causes of such inconsistencies are explored. VCM is also collated to theoretical predictions based on the published ICE-3G and ICE-4G loading history and on a model of Earth rheology characterized by stratified viscosity variations (Tushingham and Peltier, 1991; Peltier, 1994). In this study, a map of ratio between gravity changes to height changes is compiled and physically interpreted. Using VCM and geodetic height changes from CBN-GPS solution, a map of rate of geoidal height changes is also compiled and interpreted in some areas in Canada. The VCM constraints on Glacial Isostatic Adjustment (GIA) model parameters are investigated by varying, one at a time, two key parameters: 1) viscosity in different layers, and 2) the thickness of Laurentide ice over individual ice disks in Eastern Canada, and the Prairies, to obtain better fits to the VCM. In Eastern Canada, the VCM is consistent with an increase in the upper mantle viscosity. In The Great Lakes, the VCM has a better agreement with the predictions of GIA computed considering a lower viscosity for different layers of mantle. This study shows also that near the centre of rebound at Churchill, present day vertical crustal movement is most sensitive to the viscosity in the shallow part of the lower mantle and the transition zone (UM2). The VCM is consistent with a thinning of the Laurentide ice-sheet over the Prairies relative to both standard ice models. These analyses leads to better understanding of the trade-offs between Earth rheology and ice sheet history and hence some suggestions are made to improve postglacial rebound model.
A plan for coastal zone integrated resource management in a developing south west pacific island country
A plan for coastal zone integrated resource management in a developing south west pacific island country
The coastal zones of developing nations are subject to current and potential stresses of unprecedented magnitude. The health, nutrition and well being of the people of a relatively poor country such as the Solomon Islands, are directly dependent on the integrity and continued productivity of resources from these areas. The capability of government to manage effectively over the long term is the single most important prerequisite to the fulfillment of basic human needs and the ultimate achievement of sustainable development. The governments of many developing nations have begun to acknowledge the importance of these issues, but the unwillingness or inability of past colonial or current indigenous agencies to manage coastal resources and protect environmental quality has prevented effective coastal management in many cases. This thesis concentrates on the organizational and process oriented problems of coastal management associated with insufficient coordination of intra- and inter-governmental authorities and inadequate information management techniques. In this thesis an appropriate coastal management strategy, defined as Coastal Zone Integrated Resource Management (CZIRM) is introduced. Through the analysis of current coastal management programs in a number of different jurisdictions and the identification of a tool for user requirement specification, a plan for CZIRM implementation is developed.
A proposed submarine electronic chart display and information system
A proposed submarine electronic chart display and information system
The introduction of electronic charts and their display systems has greatly improved the mariner’s ability to absorb information and assess developing navigation and collision avoidance situations. NATO, recognizing the capability of these systems, has commenced development of a specialized navigation system that will extend the role of conventional ECDIS into the warship environment. This report proposes a further extension of ECDIS capabilities into the submarine environment, thus providing the modern submariner with the benefits of computer assisted navigation. The unique requirements of submarine navigation, the S-57 Electronic Navigational Chart, and the Vector Product Format’s Digital Nautical Chart are investigated. Additional requirements needed for a specialized Submarine Electronic Chart Display and Information System are then proposed and recommendations for the most suitable electronic chart product are made. A proposed product specification is included as an Appendix to the report. Review of submarine navigation identifies four new functional requirements that must be added to WECDIS to support submarine navigation. The new requirements are: real time pool of error generation; real time generation of safe depth contours; input, display and organization of water space management data; and the ability to function as a digital local operations plot. After review of the two prominent electronic charts, the Digital Nautical Chart is selected as the most suitable product for use.
A real-time software GNSS receiver development framework
A real-time software GNSS receiver development framework
This dissertation provides the architecture and describes the development effort of a modular software-based real-time global navigation satellite system (GNSS) receiver research framework using the Microsoft .NET Framework and the C# programming language. A pipelined signal-processing model is used to address key timing and intermodule synchronization challenges inherent in working with the parallelism required to simultaneously receive and process four or more satellite signals. An extensible interoperability layer provides clearly defined functional interfaces and simplifies the integration of existing hardware and software components with any stage in the signal pipeline. Various aspects of front-end hardware design requirements, as well as new acquisition and tracking mechanisms, are identified and discussed. The expected benefits of this framework development will be to establish a whole context for software receiver research and to provide a unified view of a software receiver implementation using tools and technologies that encourage the development of diverse feature-rich applications.
A regional model for the prediction of ionospheric delay for single frequency users of the Global Positioning System
A regional model for the prediction of ionospheric delay for single frequency users of the Global Positioning System
One of the major limitations to the accuracy attainable using single frequency Global Positioning Systems receivers is the propagation delay of the signals as they pass through the ionosphere, especially during times of high solar activity. Errors of several parts per million can be encountered on baselines where only one frequency has been observed. This thesis presents an approach for modelling the ionospheric delay, using phase measurements from dual frequency receivers to estimate corrections for single frequency users operating within the same region. A surface is used to approximate the spatial distribution of the delay, and temporal changes are also taken into account by the estimation of a new surface at every epoch. To test the validity of the model, data were obtained from an experiment conducted near Ottawa, Canada, in October of 1990 by the Canada Centre for Remote Sensing and the Canada Centre for Surveying. Three dual frequency receivers on the ground are used to estimate ionospheric delay variations and to correct the observations from an airborne single frequency receiver moving in the vicinity of the other three receivers. It is shown that after the model has been applied, differences between three separate solutions for the position of the aircraft, computer with respect to different monitor stations, are at a level of one part per million (ppm). Before correction these differences were at two to three ppm, with periods of up to 50 ppm. It is felt that the model although fairly simple in design, is effective in reducing the ionospheric bias sufficiently well for a broad range of applications, including remote sensing, for which the test data was obtained.

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