Sequential Likelihood Updates for User Position Estimation with GNSS Signal Strength Matching

This publication describes apparatuses, methods, and techniques for performing Global Navigation Satellite System (GNSS) shadow matching that can increase user location accuracy in an urban environment by appropriately calculating and reporting sequential likelihood (probability) updates for user location estimation. To do so, an electronic device (e.g., a smartphone) utilizes an Urban Canyon Positioning Algorithm, which uses particle filters to solve filtering problems arising in Bayesian statistical inference. The Urban Canyon Positioning Algorithm performs sequential likelihood updates for user position estimation by weighting various particles of the particle filters to account for numerous factors, such as the number of GNSS signals, the observed shape of a “constellation” of satellites of the GNSS, unmeasured physical features (e.g., buildings), local physical features, and so forth

Planning for biodiversity in the wider countryside: recognising opportunities, overcoming barriers.

There is an increasing imperative to conserve the biological diversity of the world to ensure its future viability and integrity. The traditional approach in England has been to protect a series of small, isolated sites. Recent research has demonstrated the inadequacies of this approach, suggesting a need to direct energies more towards conservation in the surrounding wider countryside. However, there are considerable difficulties associated with achieving biodiversity objectives in the wider countryside, as there is a heavy reliance on non-statutory planning mechanisms. Whereas solutions to biodiversity conservation have generally been seen to lie in the realm of natural science, this thesis recognises the need for a better understanding of the people, policies and activities involved in the process. It therefore couples social science perspectives with an understanding of ecological science principles, in order to investigate the issues affecting the implementation of biodiversity conservation plans in three case studies in south west England. By employing a range of qualitative techniques this research: defines a number of conservation objectives for the study areas; uses conservation objectives as a basis for conducting a content analysis of biodiversity planning documents, in order to uncover potential implementation opportunities and barriers; presents the results in an analytical framework; explores and refines these through a series of semi-structured interviews with key biodiversity actors. This research uncovers a complex set of interacting issues. These issues relate to partnership styles of working, building agreement and trust, variable levels of knowledge about habitat and species in the wider countryside, restoration techniques, indicative strategies, strategic targeting of resources, financial support to farmers and other land managers, the role of monitoring, and policy responses to recent agricultural crises. The results attest to the importance of a social-scientific understanding of biodiversity planning, in particular, of the forces which drive or obstruct the implementation of local solutions. The thesis concludes with a number of recommendations, based on original evidence, aimed at improving the implementation of biodiversity plans in the wider countryside

Two-dimensional aerodynamic characteristics of the OLS/TAAT airfoil

Two flight tests have been conducted that obtained extension pressure data on a modified AH-1G rotor system. These two tests, the Operational Loads Survey (OLS) and the Tip Aerodynamics and Acoustics Test (TAAT) used the same rotor set. In the analysis of these data bases, accurate 2-D airfoil data is invaluable, for not only does it allow comparison studies between 2- and 3-D flow, but also provides accurate tables of the airfoil characteristics for use in comprehensive rotorcraft analysis codes. To provide this 2-D data base, a model of the OLS/TAAT airfoil was tested over a Reynolds number range from 3 x 10 to the 6th to 7 x 10 to the 7th and between Mach numbers of 0.34 to 0.88 in the NASA Langley Research Center's 6- by 28-Inch Transonic Tunnel. The 2-D airfoil data is presented as chordwise pressure coefficient plots, as well as lift, drag, and pitching moment coefficient plots and tables

GNSS Shadow Matching in a Changing Urban Environment

This publication describes apparatuses, methods, and techniques for performing Global Navigation Satellite System (GNSS) shadow matching in a changing urban environment. To do so, a user equipment (e.g., a smartphone) utilizes a comprehensive positioning algorithm. The smartphone can measure a signal strength of satellites of the GNSS. When the signal strength matches an expected shadow, the comprehensive positioning algorithm can utilize GNSS data, area network data, inertial data, and an Urban Canyon Positioning Algorithm. The Urban Canyon Positioning Algorithm uses GNSS shadow matching data to increase user location accuracy in the urban environment. When the signal strength does not match the expected shadow, the comprehensive positioning algorithm can estimate user position using GNSS data, area network data, inertial data, and other optional localization signals (e.g., step counting, visual matches against a known model of a street-level visual map). Then, the comprehensive positioning algorithm can compare and quantify differences between the signal strength with the expected shadows, and quantify discrepancies between an estimated user location from various localization signals. Based on the differences between the signal strength and the expected shadows, the comprehensive positioning algorithm can determine and map changes in the urban environment. When the GNSS shadow matching determines user location with a high degree of confidence and accuracy, the comprehensive positioning algorithm can use this information to find discrepancies in other localization signals that rely on a map model (e.g., terrain height data, street-level visual maps, WiFi® hot spots). Lastly, the comprehensive positioning algorithm can adjust updates from the Urban Canyon Positioning Algorithm near unmodeled physical features (e.g., buildings, bridges, tunnels) in the urban environment

Performing GNSS Shadow Matching for User Equipment with Varied Carrying Positions

This publication describes apparatuses, methods, and techniques for performing Global Navigation Satellite System (GNSS) shadow matching for user equipment (e.g., smartphones) with varied carrying positions, such as in a user’s hand, pocket, purse, backpack, and so forth. To do so, the smartphone utilizes an Urban Canyon Positioning Algorithm to find line-of-sight (LOS) signals of satellites of the GNSS. Then, the Urban Canyon Positioning Algorithm estimates a signal-strength degradation of the LOS signals due to the carrying position, such as when the user puts their smartphone in their pocket. After estimating the signal-strength degradation of the LOS signals, the Urban Canyon Positioning Algorithm adjusts LOS signals and non-line-of-sight (NLOS) signals with the estimated signal-strength degradation of the LOS signals. Finally, the Urban Canyon Positioning Algorithm computes GNSS shadow matching by adjusting parameters (e.g., the median and the standard deviation) of the signal strength of all the signals (LOS and NLOS) received by the smartphone

THE BIG PICTURE - SATELLITE REMOTE SENSING APPLICATIONS IN RANGELAND ASSESSMENT AND CROP INSURANCE

Livestock Production/Industries, Risk and Uncertainty,

Defining Landscape Resistance Values in Least-Cost Connectivity Models for the Invasive Grey Squirrel: A Comparison of Approaches Using Expert-Opinion and Habitat Suitability Modelling

Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a leastcost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a leastcost approach to mapping ecological networks.This project was funded by the Forestry Commission GB and the National School of Forestry at the University of Cumbria. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

A Renormalisation group for TCSA

We discuss the errors introduced by level truncation in the study of boundary renormalisation group flows by the Truncated Conformal Space Approach. We show that the TCSA results can have the qualitative form of a sequence of RG flows between different conformal boundary conditions. In the case of a perturbation by the field phi(13), we propose a renormalisation group equation for the coupling constant which predicts a fixed point at a finite value of the TCSA coupling constant and we compare the predictions with data obtained using TBA equations.Comment: 11 pages, 7 figures, talk presented by G Watts at the workshop "Integrable Models and Applications: from Strings to Condensed Matter", Santiago de Compostela, Spain, 12-16 September 200

Using GPS telemetry to validate least-cost modeling of gray squirrel ( Sciurus carolinensis) movement within a fragmented landscape

In Britain, the population of native red squirrels Sciurus vulgaris has suffered population declines and local extinctions. Interspecific resource competition and disease spread by the invasive gray squirrel Sciurus carolinensis are the main factors behind the decline. Gray squirrels have adapted to the British landscape so efficiently that they are widely distributed. Knowledge on how gray squirrels are using the landscape matrix and being able to predict their movements will aid management. This study is the first to use global positioning system (GPS) collars on wild gray squirrels to accurately record movements and land cover use within the landscape matrix. This data were used to validate Geographical Information System (GIS) least-cost model predictions of movements and provided much needed information on gray squirrel movement pathways and network use. Buffered least-cost paths and least-cost corridors provide predictions of the most probable movements through the landscape and are seen to perform better than the more expansive least-cost networks which include all possible movements. Applying the knowledge and methodologies gained to current gray squirrel expansion areas, such as Scotland and in Italy, will aid in the prediction of potential movement areas and therefore management of the invasive gray squirrel. The methodologies presented in this study could potentially be used in any landscape and on numerous species

Experimental Heat Transfer Supporting Simulated Water Well Performance on Mars

Favorable indications of massive quantities of water on Mars have initiated studies of potential changes to human Mars missions. Using a technique known as a Rodriguez Well to melt the ice, store the resulting water in a subsurface ice cavity until needed, and then pump water to the surface for use is one potential means to effect these changes. A computer simulation of the Rodriguez Well in a terrestrial environment is one of the engineering tools being used to characterize the performance of this type of well on Mars. An experiment at the NASA Johnson Space Center is gathering data for convective heat transfer and evaporation rates at Mars surface conditions so that this computer simulation can be properly modified to predict performance on Mars. While quantitative results await processing, tests have indicated that a pool of water can be maintained at 1C to 2 C while at Mars surface temperatures and pressures