Global Positioning System Applications Research Articles

A Hemispherical 3-D Null Steering Antenna for Circular Polarization

In this letter, a compact three-dimensional (3-D) null steering antenna is presented for circular polarization. Two high-isolated circularly polarized (CP) pattern modes, the broadside and the conical CP pattern modes, are synthesized for 3-D null steering in the upper hemisphere. The broadside CP pattern mode is generated by a corner-truncated patch, and the conical CP pattern mode is generated by four rotationally symmetric strips. By controlling the exciting power ratio and the relative phase delay of the two modes, continuous null steering is achieved in the elevation plane and the azimuth plane, respectively. A prototype of the proposed antenna operating at 1.575 GHz is fabricated and tested for the global position system (GPS) applications. The simulated and measured results verify the null steering performance of the proposed design.

Where Does Bicycling for Health Happen? Analysing Volunteered Geographic Information Through Place and Plexus

Research on the role of bicycling for health through physical activity has been limited by the lack of information on where bicyclists ride. New big data sources available through smartphone-based applications provide a rich source to provide bicycle volume data more comparable to the scale of information available for automotive and public transit modes. In the case of smartphone apps for fitness tracking, results of this data can be used similar to the growing application of global positioning systems for automotive travel surveying. The authors evaluate data from Travis County, Texas for the purpose of determining where bicyclists ride, primarily for fitness purposes. Ride trip volumes are evaluated with residential and employment density, land use diversity, bicycle facilities and terrain to characterize places chosen for bicycling for health. Though limited to bicycle rides and routes voluntarily logged using the smartphone app, this method provides promise for applications in multi-modal transportation planning and health impact assessment studies.

Application of Low-Cost GPS Tools and Techniques for Landslide Monitoring: A Review

The main goal of our ongoing research is to design a low-cost continuous monitoring system for landslide investigation using the Reverse RTK (RRTK) technique. The main objectives of this paper are to review the existing Global Positioning System (GPS) tools and techniques used for landslide monitoring, and to propose a novel low-cost landslide monitoring technique using Reverse RTK GPS. A general overview of GPS application in landslide monitoring is presented, followed by a review of GPS deformation monitoring systems and some of the factors used for their categorization. Finally, the concept, principles and advantages of the proposed new landslide monitoring system are discussed.

AFFINITY PROPAGATION CLUSTERING IN DEFINING LEVEL OF SERVICE CRITERIA OF URBAN STREETS

Defining Level Of Service (LOS) criteria is very important as this is the first step of LOS analysis but this is not well defined in Indian context. The analysis followed in India is basically adaptation of Highway Capacity Manual (HCM 2000) methodology which is more suitable for developed countries having homogenous traffic pattern. An attempt has been made in this study to define LOS criteria of urban streets for developing countries having heterogeneous traffic flow condition. Defining LOS is basically a classification problem and to solve it Affinity Propagation (AP), a very recently developed cluster algorithm is used. Inventory details and the required speed data are collected from five major street corridors of Greater Mumbai Region in India through the application of Trimble GeoXT Global Positioning System (GPS) receiver. Six validation parameters are used on Free Flow Speed (FFS) data to find the optimal number of clusters, which is required for the classification of street segments into number of classes. After that speed data collected during both peak and off-peak hours are averaged over street segments and clustered into six groups to get the speed ranges of different LOS categories. Using validation parameters, considering the physical and surrounding environmental characteristics it is found that street segments can be classified into four classes in Indian context as mentioned in Highway Capacity Manual 2000. However, the FFS range for urban street class IV (urban design category) is significantly lower because of varying road geometric characteristics. The speed ranges of LOS categories under urban street classes are proportionately lower to that values mentioned in HCM 2000 because of highly heterogeneous traffic flow on urban Indian roads. The travel speed data collection procedure using GPS is simple and accurate. In addition, AP clustering is highly efficient in terms of time saving and provides a very accurate solution to classification problems. Hence, both GPS and AP techniques can be applied in other countries to define the speed ranges of LOS categories considering the local conditions.

A multiarm curl antenna for GPS applications

A single-feed dual-band antenna with wide-beam circularly polarized (CP) radiation is introduced for application in the global positioning system (GPS). The primary radiating element is a planar multiarm curl antenna. The dual-band operation is achieved by dividing the arms of the antenna into two branches of different lengths. To generate CP radiation, the radiator is fed by double vacant-quarter printed rings, which allows direct matching of the antenna to a single 50 Ω coaxial line. To enable unidirectional CP radiation and improve the 3 dB axial ratio (AR) beamwidth, the planar multiarm curl radiator is backed by a rectangular cavity-backed reflector. The final design, with an overall GPS-L2 frequency size of approximately λo/2.45 × λo/2.45 × λo/8, resulted in a |S11|<–10 dB bandwidth of 1.221–1.282 GHz (4.9%) and 1.546–1.660 GHz (7.1%) and a 3 dB AR bandwidth of 1.212–1.240 GHz (2.2%) and 1.560–1.590 GHz (1.9%). Furthermore, it showed excellent right-hand CP (RHCP) radiation at both operating bands, namely wide beamwidth, similar gain, a high front-to-back ratio, and high radiation efficiency.

Single‐pin, single‐layer, dual‐band patch antenna for global positioning system and satellite digital audio radio system automotive applications

A low-cost, reduced-size, single-feed, single-layer microstrip patch antenna is presented that receives right-hand circularly polarised satellite signals for the global positioning system's L1-Band (1575.42 MHz) and left-hand circularly polarised satellite signals and vertically linearly polarised terrestrial signals for the satellite digital audio radio system band (2320-2345 MHz). The proposed antenna is constructed of a main central patch and a ring surrounding it, both with truncated corners to achieve the desired circular polarisation characteristics. The two patches are connected to each other using four long and thin microstrip transmission lines. The design, simulation and measured results are presented. The effects of varying key antenna physical parameters were carefully examined and discussed in detail to characterise their effects on operational bandwidth.

Research on the regional short-term ionospheric delay modeling and forecasting methodology for mid-latitude area

The modeling and forecasting of the ionospheric delay is crucial in Global Positioning System (GPS) applications. In this study, a mathematical model that combines the polynomial function with B-spline function is put forward to estimate the regional ionospheric delay. In order to increase the forecasting accuracy, an integration forecasting method based on Holt---Winter model and Markov model is proposed to forecast the regional ionospheric delay. The Holt---Winter model is used to forecast the periodicity of vertical total electron content (VTEC), and the Markov model is employed to refine the residuals produced by the Holt---Winter model and forecast the fluctuation of VTEC. The two approaches are applied to real data obtained from the ground-based GPS observations of Jiangsu Continuously Operating Reference Stations. The results illustrate the effectiveness of the 2-h interval ionospheric delay modeling method, and the feasibility of the short-term ionospheric delay forecasting method for mid-latitude area. The applicability of the methodology during the ionospheric storms in the low-latitude area is also discussed.

Design of Dual Band Circular Polarization Stacked Microstrip Antenna for GPS Applications

In this paper dual-band microstrip antenna for Global Positioning System (GPS) application is designed.This design contents on two circular patch ( upper circular patch, lower circular patch) printed on a two-layer substrate of an FR4 dielectric layer, and cutting a crossed-slot in the upper patch and four I slots in the lower patch. The antenna can work at GPS Ll band (1.575GHz) and L2 band (1.227GHz). The design achieved an approximately impedance bandwidth of 15.8 MHz for L1 for two ports, while L2 band is 11.8 MHz for two ports with maximum gain of 2.54dBi and 1.177dBi in the L1 and L2 band respectively for two ports. The resulting circular polarization (with axial ratio ≤ 3 dB) has been found to meet that required for this application. The VSWR is approximately1.1 (VSWR ≤ 2) for L1 and 1.2 for L2. Results were obtained above using the software CST, which shows that this antenna can meet the demands of the signals of satellite navigation system.The antenna dimensions are (70*70 mm 2 ). The structure is compact and has a good application prospect. The results with low-profile characteristics make the antenna suitable for GPS applications. Keywords: microstrip antenna, GPS antenna, Circular polarization, dual-band antenna, Global Positioning System.

Verified stochastic methods in geographic information system applications with uncertainty

Modern localization techniques are based on the Global Positioning System (GPS). In general, the accuracy of the measurement depends on various uncertain parameters. In addition, despite its relevance, a number of localization approaches fail to consider the modeling of uncertainty in geographic information system (GIS) applications. This paper describes a new verified method for uncertain (GPS) localization for use in GPS and GIS application scenarios based on Dempster-Shafer theory (DST), with two-dimensional and interval-valued basic probability assignments. The main benefit our approach offers for GIS applications is a workflow concept using DST-based models that are embedded into an ontology-based semantic querying mechanism accompanied by 3D visualization techniques. This workflow provides interactive means of querying uncertain GIS models semantically and provides visual feedback.

Dual‐band microstrip‐fed bow‐tie antenna for GPS and WLAN application

ABSTRACTA novel microstrip‐fed bow‐tie antenna for the global positioning system (GPS) and wireless local area network (WLAN) applications is presented in this letter. The proposed antenna consists of two pairs of printed bow‐tie patches with different dimensions, which can generate dual‐band characteristics independently. Based on this design concept, a prototype of the dual‐band antenna is fabricated and measured. The simulated and measured reflection coefficients, together with the radiation patterns, are presented and compared. Measurements show that the 10‐dB impedance bandwidth of the proposed dual‐band bow‐tie antenna is about 670 MHz (1.22–1.89 GHz) and 1130 MHz (5.24–6.37 GHz), which can cover both the GPS and WLAN bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2088–2091, 2014

A NOVEL VARIABLE RATE PNEUMATIC FERTILIZER APPLICATOR

The canopy prevents the use of global positioning system based fertilizer applicators in oil palm plantations. Hence, a radio frequency identification triggered variable rate pneumatic fertilizer system was developed for this application. A real-time embedded system was used as the core controller, LabVIEW software was used to program and coordinate the operations of the embedded system and the host computer. A speed measuring unit was used to provide feedback to the system. A field test was conducted to examine the response time. The sensors were calibrated in the laboratory and the measurement linearity had regression coefficients close to 1. Two to three seconds were required for the device to respond to changes in application rate. It is expected that this approach will become an alternative in plantations where the canopy hinders proper application of global positioning systems.

A high linearity SiGe HBT LNA for GPS receiver

A high linearity 1.575 GHz SiGe:HBT low noise amplifier (LNA) for global positioning system applications is described. The bipolar cascoded with an MOSFET LNA was fabricated in a commercial 0.18 μm SiGe BiCMOS process. A resistor bias feed circuit with a feedback resistor was designed for the LNA input transistor to improve its intermodulation and compression performance. The packaged chip tested on board has displayed a noise figure of 1.11 dB, a power gain of 18 dB, an output 1 dB compression point of +7.8 dBm and an input third-order intercept point of +1.8 dBm. The chip occupies a 500 × 560 μm2 area and consumes 3.6 mA from a 2.85 V power supply.

Six-minute walk test closely correlates to “real-life” outdoor walking capacity and quality of life in patients with intermittent claudication

We used outdoor walking distance measured during 40 minutes as "real-life" outdoor walking capacity in 49 patients with intermittent claudication (IC). The outdoor walking distance was measured by a global positioning system application for a smartphone. The relationships of self-reported maximum walking distance (SR-MWD), the MWD on a graded treadmill test, and the 6-minute maximum walk distance (6MWD) vs outdoors walking capacity were investigated. Also studied were the associations of SR-MWD, MWD, and 6MWD with health-related quality of life assessed with the disease-specific instrument the Vascular Quality of Life Questionnaire (VascuQoL). In this prospective observational cohort study, 49 IC patients underwent an outdoor walking capacity test for 40 minutes, and MWD and 6MWD were measured. SR-MWD was recorded, and all subjects completed the VascuQoL questionnaire. Associations between the different walk estimates and outdoor walking capacity and health-related quality of life were investigated by correlation analysis (Spearman ρ). Outdoor walking distance during 40 minutes was a median 2495 m (range, 1110-3300 m). SR-MWD correlated moderately and MWD correlated strongly to outdoor walking capacity (r = 0.56 and r = 0.65; P < .001, respectively). The 6MWD test showed the largest correlation to the outdoor walking capacity (r = 0.78; P < .001). The 6MWD was the only test that showed correlations with the VascuQoL sum score (r = 0.53; P < .01) and all of the domain scores, whereas SR-MWD and MWD showed weak correlations to the VascuQoL. The distance walked during the 6-minute walk test is closely correlated to outdoor walking capacity and health-related quality of life in IC patients. Our data support the use of 6MWD for routine clinical evaluation of walking capacity in IC patients.

Compact circularly polarized microstrip antenna for GPS applications

ABSTRACTA compact design of circularly polarized microstrip antennas is described. The antenna has a square‐ring radiating patch, and it is excited by a feeding network consisting of a quadrature coupler with dual lumped capacitors and an impedance‐matching circuit. The feeding network has a considerably smaller size than a traditional 90° hybrid, and therefore, it is placed at the inner slot of the square‐ring patch. By tuning the capacitance value of the lumped capacitors, the antenna can generate good circular polarization radiation. An antenna prototype designed for global positioning system applications is implemented. From the measured results, the 10 dB‐return‐loss bandwidth and 3 dB‐axial‐ratio bandwidth of the prototype are 3% and 1%, respectively. Simulation results obtained by HFSS are also provided to validate the experiment. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1293–1296, 2014

Validating One-On-One GPS Instruction Methodology for Natural Resource Area Assessments Using Forestry Undergraduate Students

Undergraduate students pursuing a Bachelor of Science in Forestry (BSF) at Stephen F. Austin State University (SFA) attend an intensive 6-week residential hands-on instruction in applied field methods. The intensive 6-week instruction includes learning how to use the Global Positioning System (GPS) with a Garmin eTrex HCx GPS unit to accurately calculate area. Students were instructed how to assess the accuracy of their GPS collected waypoints by calculating the Root Mean Square Error (RMSE) comparing their GPS collected area measurements with instructor on-screen digitized area. Student’s average area RMSE between digitized and GPS derived area was 0.015 hectares, whereas instructor’s average area RMSE between digitized and GPS derived area was 0.015 hectares. Over 76% of students measured GPS area was within 5% of instructor on-screen digitized area. No difference between the students and instructors area RMSE of 0.015 hectares and high level of agreement between student measured GPS area and instructor on-screen digitized area: (1) indicates students receiving hands-on instruction in GPS applications can record accurate area measurements after only a limited 2 hour introduction; (2) the accuracy of the Garmin eTrex HCx GPS unit is not user dependent; and, (3) validates the interactive hands-on instruction methodology employed at SFA.

GPS-based slope monitoring systems and their applications in transition mining from open-pit to underground

Combining methods of open-pit and underground mining can yield maximum economic outcomes, while they may also cause large-scaled geological hazards, such as landslides. Failure to prevent landslides in mining areas could result in losses and damages to equipment, surrounding environments, and even human lives. In this paper, we report the application of global positioning system (GPS) for monitoring the Anjialing Coal Mine, the first mine in China that employs the combining methods of open-pit and underground mining. Mine slopes with different inclined angles were monitored and precise data of ground movements were obtained. Mathematic modelling of the subsidence rate over time has successfully detected the occurrence of terminal subsidence rate and a corresponding a landslide. The equipment and persons involved were evacuated and kept safe before the medium landslide occurred. In conclusion, the GPS monitoring system is proved to be effective in mitigating the geological hazards in mining areas.

MULTIBAND PROBE-FED STACKED PATCH ANTENNA FOR GNSS APPLICATIONS

A novel design of multiband probe-fed stacked patch antenna for Beidou Satellite Navigation System (BDS) and Global Position System (GPS) applications is proposed. The presented antenna covers BDS-1 L (1616 ± 5 MHz), BDS-1 S (2492 ± 5M Hz), BDS-2 B1 (1561 ± 5M Hz) and GPS L1 (1575±5 MHz) frequency bands. Excellent high port isolation and Circular Polarized (CP) performance are achieved by introducing four metallized holes which are strictly symmetrical about the centre of the patch antenna. The proposed antenna is fabricated, and its performance is verified in measurement.

Broadband Circularly Polarized Microstrip Antenna with Coplanar Parasitic Ring Slot Patch for L-Band Satellite System Application

A novel capacitive-coupled probe-fed circularly polarized (CP) microstrip antenna with coplanar parasitic ring slot patch has been proposed for the International Maritime Satellite (INMARSAT) and the Global Positioning System (GPS) applications. The key feature of the design is employing capacitive-coupled four-probe feeds to increase impedance bandwidth and adopting coplanar parasitic ring slot patch to enhance CP bandwidth. The feed network is compact and neat using only T-junction power dividers and phase shifters with shunted short-circuited microstrip stubs for lightning protection. The characteristics of the proposed antenna have been studied by simulation and experiment. The final antenna can produce a ${ S}_{11} 14 dB impedance bandwidth of nearly 27%, a 3-dB axial-ratio bandwidth of nearly 16%, and a gain of higher than 8 dB in the whole maritime satellite communication work band.

Economical Applications of GPS in Road Projects in India

The Global Positioning System (GPS) is a satellite based navigation system made up of a network of 24 satellites placed into orbit by U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, they made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24hours a day. Therefore it has become a widely deployed and useful for commerce, scientific uses, tracking and surveillance. GPS's accurate time facilitates everyday activities such as banking, mobile phone operations and even the control power grids by allowing well synchronized hand-off switching. In general GPS applications are realized in following:•In Air – navigation by general aviation and commercial aircraft•At Sea – navigation by recreational boaters, commercial fishermen, and professional mariners•For Surveyors – cost saving by drastically reducing setup time at the survey and providing incredible accuracyAll above applications employ the service of 4- satellites in the orbit at any point of time. In this paper a new method is suggested for which, software is being developed to get the GPS outputs making use of data from a single satellite. The software is known as ‘Geomatic Engineering Application software’. Its use will bring saving of hiring time of 3- satellites, therefore it would cut down the financial implication to a large extent in any project. GPS application in Road projects is discussed herein with this new concept.

Precipitable water vapor estimation in India from GPS-derived zenith delays using radiosonde data

One of the most recent applications of global positioning system (GPS) is the estimation of precipitable water vapor (PWV). It requires proper modeling to extract PWV from zenith wet delay (ZWD). The existing global models take no account of latitudinal and seasonal variation of meteorological parameters in the atmosphere. In fact, they ignore the atmospheric conditions at a specific location. Therefore, site-specific PWV models have been developed for five stations spread over the Indian subcontinent, using 3-year (2006–2008) radiosonde data from each of these stations. Furthermore, a similar regional PWV model is also developed for the Indian region. The purpose of the developed site-specific as well as regional model was to convert ZWDs into PWV without using surface meteorological parameters. It has been found that the developed regional and site-specific PWV models show about mm-level accuracy in estimating PWV using derived ZWD from radiosonde as input. The developed site-specific, regional models were also used to extract PWV from GPS-derived ZWD at Bangalore and New Delhi. The accuracy of the developed site-specific and regional model is of the same level. The PWV accuracy obtained with the developed regional model is about 6.28, 6.6 mm in comparison to radiosonde PWV at Bangalore and New Delhi, respectively.