Use Of Global Positioning System Research Articles

Assessing and Maximizing the Acceptability of Global Positioning System Device Use for Studying the Role of Human Movement in Dengue Virus Transmission in Iquitos, Peru

As use of global positioning system (GPS) technology to study disease transmission increases, it is important to assess possible barriers to its use from the perspective of potential study participants. Fifteen focus group discussions stratified by sex, age, and motherhood status were conducted in 2008 in Iquitos, Peru. All participants said they would accept using a GPS unit for study purposes for 2-4 weeks. Participants' main concerns included caring properly for the unit, whether the unit would audio/videotape them, health effects of prolonged use, responsibility for units, and confidentiality of information. A pilot study was then conducted in which 126 persons were asked to carry GPS units for 2-4 weeks; 98% provided consent. All persons used the units expressing minimal concerns, although 44% reported forgetting the device at least once. Our study is the first to highlight participant concerns related to use of GPS for long-term monitoring of individual behavior in a resource-limited setting.

Modeling Operating Speed and Deceleration on Two-Lane Rural Roads with Global Positioning System Data

In the road design process, speed variation along the road segment is an important issue to consider in adapting road geometry to drivers' expectations. To achieve this objective, speed criteria are used to evaluate road consistency. Being able to estimate the operating speed in the design phase can lead to safer road alignment. With this objective, several researchers have developed operating speed models. Most of these models are based on collected spot speed data. They assume constant speed on curves and, therefore, deceleration that occurs entirely on the approach tangent. According to these assumptions, spot speed data are collected at the center of the horizontal curve and at the midpoint of the preceding tangent to obtain operating speed models. This paper presents a new methodology based on the use of Global Positioning System devices that allow continuous collecting and processing of speed data. With this new methodology, not only can new and more accurate operating speed models be developed, but cited hypotheses can also be checked. Observed speed continuous profiles allow studies that previously could not be done, especially as related to deceleration and speed variations. This study calibrated new speed models, including three for horizontal curves with a radius curve and the curvature change rate of a single curve as explanatory variables, and one for tangents that incorporates the curve speed model. Tangent-curve speed variations are evaluated, with comparison of Δ85V and ΔV85, analysis of the deceleration length occurring on a curve, and development of two deceleration models.

Effects of Antenna Orientation and Vegetation on Global Positioning System Telemetry Collar Performance

Abstract Use of global positioning system (GPS) collars to improve our understanding of bear movements and habitat use has increased markedly in the last 10 years. Habitat use has been better defined using this technology, but variation in acquisition rates across covertypes and with varying antenna orientation could bias results. I assessed the effects of vegetative habitat characteristics and antenna orientation on percent of successful fixes and 3-dimensional (3D) fixes for GPS collars designed for Ursus americanus (American Black Bear) in Michigan during April–July, 2001–2002. I placed collars in 5 habitats with varying tree density, diameter, and canopy cover and also in an unobstructed area with antennas oriented 0–90° from horizontal. Basal area was the only habitat parameter measured that influenced fix success; the correlation was negative. Percent of successful locations obtained in the open area decreased as antenna orientation increased away from the vertical position. Habitat characteristics ...

Comparison of COSMIC radio occultation refractivity profiles with radiosonde measurements

In recent years, radio occultation (RO) technology making use of global positioning system (GPS) signals has been exploited to obtain profiles of atmospheric parameters in the neutral atmosphere. In this paper, the RO refractivity profiles obtained from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission are statistically compared with the observations of 38 radiosonde stations provided by the Australian Bureau of Meteorology during the period from 15 July 2006 through 15 July 2007. Different collocation criteria are compared at first, and COSMIC RO soundings that occur within 3 hours and 300 km of radiosonde measurements are used for the final statistical comparison. The overall results show that the agreements between the COSMIC refractivity profiles and the radiosonde soundings from the 38 stations are very good at 0–30 km altitude, with mean absolute relative refractivity deviations of less than 0.5%. Latitudinal comparisons indicate that there are negative refractivity deviations in the lower troposphere over the low latitude and middle latitude regions and large standard deviations exist in the lower troposphere of low latitude regions, which can reach up to ≈6%. The comparisons of COSMIC RO refractivity profiles and radiosonde observations for 3 polar stations in four different seasons indicate that the accuracy of GPS RO profiles is better in the Austral summer and autumn than in the Austral spring and winter during the year from September 2006 to August 2007.

Comparing Global Positioning System and Very High Frequency Telemetry Home Ranges of White‐Tailed Deer

ABSTRACT Use of Global Positioning System (GPS) collars on free‐ranging ungulates overcomes many limitations of conventional very high frequency (VHF) telemetry and offers a practical means of studying space use and home range estimation. To better understand winter home ranges of white‐tailed deer (Odocoileus virginianus), we evaluated GPS collar performance, and we compared GPS‐ and VHF‐derived diurnal home ranges (for the same animals) and GPS‐derived home range estimates for diurnal and nocturnal locations. Overall, the mean fix success rate of our GPS collars was 85% (range = 14–99%). Kernel density estimates of home range (using the 95% probability contour) derived from GPS and VHF locations were generally similar, as were GPS‐derived diurnal and nocturnal home ranges. Overlap indices between GPS and VHF utilization distributions (UDs) ranged from 0.49 to 0.78 for the volume of intersection (VI) index and from 0.67 to 0.94 for Bhattacharyya's affinity (BA); overlap indices for GPS‐diurnal and nocturnal UDs ranged from 0.29 to 0.81 for VI and from 0.56 to 0.94 for BA. Despite similarities of home ranges estimated from GPS versus VHF locations and GPS‐diurnal versus nocturnal locations, our data also indicate that differences may have important implications for studies focused on deer use of space, habitat, and resources at a finer scale.

Vehicle Localization Via Sensor Fusion Using Evidence Theory

ABSTRACT: In this paper a novel method which provides 2-D position of a vehicle is proposed. This method makes use of global positioning system (GPS) measurement as well as odometric data and a digital road map. Here, we propose to fuse GPS and odometer with digital road map by employing the evidence theory to maintain a correct estimate of the location of a vehicle. The goal of the fusion is to exploit the advantages of each sensor while trying to mitigate their individual limitations. It involves combining the measurement results from different sensors in order to provide knowledge that is not evident from individual sources. The objective in using this combination is to reduce the position error in the presence of slippage, satellite masking, or signal degradation due to multi-path effects. Experimental results show the effectiveness of the use of the evidence theory in the positioning system.

Using GPS-based link exclusion to reduce overhead and increase route reliability in FTP/TCP-based MANETs

In this paper, we show that the use of global positioning system (GPS) information in a mobile ad hoc network (MANET) running the file transfer protocol (FTP) over the transmission control protocol (TCP) can be used to block the inclusion of unreliable links within a discovered route by not allowing the nodes outside of a given distance to participate in their formation. In doing so, this creates more reliable routes over time and lowers the amount of network overhead necessary to maintain the flow of data packets. This approach to route formation is validated using the NS-2.31 network simulator under different types of multipath fading models as well as varying network dimensions and node densities. While this GPS blocking scheme has been explored previously in a constant bit rate (CBR) over a user datagram protocol (UDP) setting, it has not yet been tested previously under the more common real-world conditions of FTP running over TCP.

Monitoring Sandy Shores Morphologies by DGPS—A Practical Tool to Generate Digital Elevation Models

Abstract The highly dynamic nature of some sandy shores with continuous morphological changes require the development of efficient and accurate methodological strategies for coastal hazard assessment and morphodynamic characterisation. During the past decades, the general methodological approach for the establishment of coastal monitoring programmes was based on photogrammetry or classical geodetic techniques. With the advent of new geodetic techniques, space-based and airborne-based, new methodologies were introduced in coastal monitoring programmes. This paper describes the development of a monitoring prototype that is based on the use of global positioning system (GPS). The prototype has a GPS multiantenna mounted on a fast surveying platform, a land vehicle appropriate for driving in the sand (four-wheel quad). This system was conceived to perform a network of shore profiles in sandy shores stretches (subaerial beach) that extend for several kilometres from which high-precision digital elevation model...

Accurate Sensor Position Estimation for Wireless Sensor Networks Using Neighborhood Relationship

Sensor node localization is an important issue in wireless sensor networks (WSNs) due to the dynamic nature of sensor deployment. Generally, in wireless sensor network localization, the absolute positions of certain anchor nodes are required based on the use of global positioning systems, then all the other nodes are approximately localized using various algorithms based on a coordinate system of the anchors. This paper proposes a neighbor position-based localization algorithm (NPLA) that can greatly enhance the positioning accuracy when compared with current overlapping connectivity localization algorithms that attempt to use the observation of connectivity to a set of anchors to determine a node's position. The proposed method localizes the sensor nodes using both the anchors' positions and neighbor node information. However, unlike existing overlapping-based methods, the proposed NPLA does not assume the same radio transmission range. A simulation study is used to demonstrate the positioning accuracy of the proposed method with different anchor and sensor node densities.

Reducing Burden and Sample Sizes in Multiday Household Travel Surveys

Traditional household travel surveys ask respondents to report their travel behavior for a 24-h period, even though it is well known that travel patterns vary from day to day. Although this information provides an indication of average household behavior or travel on an average weekday, evidence suggests this method may not be the most cost-effective way to collect the data because day-to-day travel variability is substantial, requiring larger sample sizes. In addition, collecting multiday data provides a richness of information that simply cannot be captured with a 1-day survey, offering insights into, for example, differences in weekday versus weekend travel, the longer-term travel impacts of flexible work hours, and trip substitution and cycling patterns that emerge over the course of a week or more. Despite the intuitive appeal of multiday surveys, few examples and little information on sampling issues and sample size requirements are available. Given this situation, the reasons given for not doing multiday surveys (which center around respondent fatigue), why these issues are fast becoming irrelevant (through the use of new passive data-recording technologies), the sample size implications of extending a survey, and the potential for estimator efficiency and cost savings (even accounting for the cost of new technologies) when conducting multiday surveys are explored. The use of Global Positioning System–based travel distance data from Adelaide, South Australia, indicates that the sample size reductions are large; collecting multiday data is feasible, offering a richness not available in 1-day data; and the method results in cost-effective gains in estimator efficiency.

Use of Global Positioning System to Identify Crash Locations in South Carolina

To overcome some of the issues with geocoding crash data based on traditional location referencing systems (i.e., route and distance to intersection, route and milepoint, or both), the South Carolina Department of Transportation purchased Global Positioning System (GPS) units for all enforcement agencies in South Carolina responsible for reporting crashes. Reporting officers were instructed to use the GPS units to determine coordinate location data for recording on the crash report. Some of the problems experienced when trying to geocode 3 years (2004 to 2006) of crash data for use in safety analysis are discussed. Overall, approximately 80% of the crash records were located within reasonable levels of accuracy. Trends in the errors over the 3 years indicate a potential for targeted training to significantly reduce error. Recommendations are provided to help improve the success rate of the geocoding process. These recommendations focus on training officers and data entry personnel, designing data entry filters, and possibly changing the crash report form.

Habitat use by black bears in relation to conspecifics and competitors

Sympatric black bears ( Ursus americanus) and brown bears ( Ursus arctos) are common in many boreal systems; however, few predator assemblages are known to coexist on a single seasonally abundant large prey item. In lowland southwestern interior Alaska, black bears and brown bears are considered the primary cause of moose ( Alces alces) calf mortality during the first 6 weeks of life. The objective of this study was to document habitat use of global-positioning system (GPS)-collared black bears during peak and non-peak seasons of black bear-induced and brown bear-induced moose calf mortality within southwestern interior Alaska, in spring 2002. We compared habitats of GPS-collared black bears to those of presumably uncollared black bears and brown bears at their moose calf mortality sites. Results from this study suggest that GPS-collared black bears use similar habitat as conspecifics more than expected during the peak period of black bear predation on moose calves, whereas they use habitat in proportion to home range availability during the peak in brown bear predation on moose calves. Sex-specific Ivlev's electivity indices describe greater than expected use of mixed-deciduous forest and needleleaf forest by male GPS-collared black bears during the peak of moose calf predation, whereas females have a tendency to use these habitats less than expected. Juvenile GPS-collared black bears largely use the same habitat as other sympatric predators during the peak of moose calf predation, whereas during the non-peak period juveniles use opposite habitats as adult GPS-collared black bears. The outcome of this study offers possible explanations (e.g., sex, age) for spatial overlap or segregation in one member of a complex predator guild in relation to a seasonal pulse of preferred prey.

Perceived GPS Use and Weather-Related Decision Strategies Among Pilots

This study sought to examine the relation between visually rated pilots' perceived use of global positioning systems (GPS) as a primary source of navigation and their perceived approach to decision making during encounters with deteriorating weather conditions in flight. A total of 177 pilots completed a questionnaire in which they were asked to indicate the frequency with which they use GPS as a primary source of navigation, the decision strategy that is most like the strategy that they engage during in-flight weather-related decision making, and their perception of the significance of 9 weather-related cues as the basis for decision making. Overall, the results revealed a relation between the perceived use of GPS as a primary source of navigation and the use of aspects of prototypical or tactical decision strategies. Relations were also evident between the perceived use of GPS and the perceived significance of weather-related cues. It was concluded that the introduction of advanced technology systems such as GPS may be associated with a qualitative change in the way in which pilots acquire task-related information and formulate decisions. These outcomes are discussed in terms of a number of applied interventions.

The Use of Global Positioning System (GPS) to Monitor Training and Model Performance in High School Cross Country Runners

The Use of Global Positioning System (GPS) to Monitor Training and Model Performance in High School Cross Country Runners

Use of Global Positioning System (GPS) Watches and Accelerometry to Monitor Mobility in Older Adults

Use of Global Positioning System (GPS) Watches and Accelerometry to Monitor Mobility in Older Adults

Prediction Schemes to Enhance the Routing Process in Geographical GPSR Ad Hoc Protocol

Geographical routing protocols have received a serious attention due to more advantages they have in comparison to the conventional routing protocols. They require information about the physical position of nodes needed to be available. Commonly, each node determines its own position through the use of Global Positioning System (GPS) or some other type of positioning service. Greedy Perimeter Stateless Routing (GPSR) protocol, which is one of geographical routing protocols, limits the forwarding decision of the packet based on the node′s own position, the destination′s position and the position of the forwarding node′s neighbors. Location information has some inaccuracy depending on the localization system and the environment exists in. This paper aims to study the impact of mobility metrics (beacon interval, and node speed) on introducing location information error in GPSR protocol using different mobility models. The effect of these metrics is identified in GPSR as Neighbor Break Link (NBL) problem. Based on simulation analysis, mobility prediction schemes are proposed to migrate the observed problem.

Les Problèmes De Gestion De Flotte En Temps Réel

Thanks to the evolution of information and communication technologies, a transportation carrier may modify routes that are previously defined, in particular by the use of global positioning systems. Thus, the company may increase its profits and propose a better quality of service to its customers. To help the manager to exploit these new data flows, new decision support methods are then needed and must be developped. The goal of this paper is to formulate a definition of the fieet management problem in real time, to classify its features and to detail all elements defining this problem type. Finally, a survey of different probleni solving approaches is proposed.

Use of Global Positioning System in mine landscaping and visual impact assessment: A case study

The satellite-based Global Positioning System (GPS) needs a clear view of sky for determining a geodetic position and hence it is particularly suitable in overall projects of open-pit recovery and landscape restoration. The purpose of such measurements is to make highly accurate topographic maps thus forming the backbone of a project. In the work presented here geodetic measurements are combined with advanced visualisation techniques and GIS applications in a possible recovery plan of the abandoned excavations of Bonucoro in the mining district of Orani, central Sardinia, Italy. Considering the naturalistic and geographic settings of the mining area and its surroundings, a few proposals concerning the re-utilisation of these excavations are presented. The preparatory work consisted of the area characterisation by carrying out a topographic survey followed by a geodetic control network establishment by the GPS to describe the morphological features of the landscape and for the subsequent three-dimensional analysis and geoprocessing. The final step involved the use of VueInfinite, a computer program capable to integrate graphical data with geological and morphological attributes. It was also able to create a virtual 3D scene of a present, past, or future landscape required for visual impact assessment.

The Use of Global Positioning Systems to Record Distances in a Helicopter Line-Transect Survey

Methods that allow unbiased estimation of animal abundance are increasingly demanded in management and conservation. The use of these methods should respect their assumptions. The need for accurate distance measurements in distance-sampling surveys is stressed. Here we present 2 alternative methods for measuring distance from a line to an object during helicopter surveys: 1) using a Global Positioning System (GPS) unit, with distances measured using appropriate software; and 2) recording declination angles and altitudes, using basic trigonometry to obtain the appropriate distances. These are compared to distances measured by a laser rangefinder (assumed to be true distances). The effect of the different errors on estimated densities is assessed by simulation. The GPS method appeared to be very accurate, while a potential downward bias in estimated density could be present if the inclinometer method is used. We discuss the implication for wildlife studies of using different measurement methods leading to different errors.

The Use of Global Positioning and Geographical Information Systems in the Management of Extensive Cattle Grazing

The results of a study aimed at verifying the possible use of global positioning system (GPS) and geographical information system (GIS) technologies to understand the behaviour of domestic and wild animals bred for extensive grazing are presented. For this purpose an experimental survey was carried out in order to track animal location in the various grazing areas at the Animal Research Center of the University of Kentucky. The data have been analysed and indicate some potentially positive and useful technical applications. Using GPS, it is possible to automatically gather data with increased accuracy in the locations. Applications of GIS have proved suitable for data processing (resting and grazing times, available land surfaces, etc.). It has furthermore been determined how the ‘kernel home-range’ method may be used to reach objective conclusions on territorial and biological matters in order to solve problems of environmental planning connected with extensive cattle grazing.