Global Positioning System Processing Research Articles

Systematic review of best practices for GPS data usage, processing, and linkage in health, exposure science and environmental context research

Global Positioning System (GPS) technology is increasingly used in health research to capture individual mobility and contextual and environmental exposures. However, the tools, techniques and decisions for using GPS data...

Lora Based Elephant Detection System Near Railroads

A Lora-based elephant detection system near railroad tracks is a proposed solution to mitigate human-elephant conflicts where elephants roam railroad tracks and threaten human safety and elephant welfare. The system supports Lora (Low Range Radio) communication, image processing, and IoT (Internet of Things) devices such as MCU (microcontroller unit), GPS (Global Positioning System), LCD (liquid crystal display), speakers, and image processing. use a combination of algorithms. The system aims to detect elephants in real-time through image processing and use Lora communications to transmit information to relevant authorities and intervene in time. This white paper reviews existing literature and research in the area of ​​elephant detection systems, including research on image processing, IoT-based wildlife monitoring, and Lora communications. The proposed system has the potential to contribute to the effective detection and deterrence of elephants near railway tracks , reduce the risk of human-elephant collisions, and improve elephant conservation efforts.Top of Form

Design of field programmable gate array-based data processing system for multi global positioning system receiver

<span>A global positioning system (GPS) sensor is needed for a ballistic/moving object to do position tracking. In previous study, a multi GPS processing system was made using several microcontrollers and data processing cannot be done simultaneously. Therefore, it was considered as ineffective system. In this research, field programmable gate array (FPGA)-based data processing system for multi-GPS receiver was proposed. The proposed system was designed to reduce root mean square error (RMSE). There are two main processes in the proposed system which work in parallel, i.e. data parsing and data processing. Raw data from GPS receiver was collected and calculated to get average value, then sent it through serial communication to show result. Experimental results <span>confirm the RMSE value of the proposed system is smaller than the conventional one. The RMSE for latitude, longitude, and altitude decrease by 38.46%, 58.28%, and 24.</span>80%, respectively.</span>

Utilization of Indonesia’s regional ionosphere model to improve the accuracy of GPS measurements to support disaster mitigation studies

Ionospheric can cause severe degradation of GPS (Global Positioning System) functionality and decrease coordinate accuracy. Increasing the precision of GPS station coordinates will improve accuracy in many applications. Many applications can use GPS for deformation studies, such as geodynamic studies, active fault studies, volcanic deformation monitoring, land subsidence studies, and hazard mitigation studies. We can use global ionospheric correction to produce better coordinates by utilizing post-processing GPS data. With the increasing number of GPS stations in Indonesia, it is possible to develop regional ionosphere models. This study computes regional ionospheric models from real-time streaming GPS data and uses them in GPS processing. Regional ionospheric models can increase the accuracy of GPS station coordinates by 5% -10% compared to global ionosphere models (igsg and codg).

Scope of paddy harvesting technologies through cropland mapping using GIS tools and remote sensing

Nowadays, modern agriculture has benefited from Precision Agriculture (PA) through incorporation of technological advances like the use of GIS (Geographic Information Systems), RS (Remote Sensing), GPS (Global Positioning System) and advanced information processing. Based on the GIS, RS and GPS, a study was conducted to develop a cropland map using GIS and remotely sensed unsupervised algorithm for suitability analysis of paddy harvester. The research was carried out at four selected locations such as Kulbaria-Baratia, Mundopasha, Charwapda, and Holdibaria villages of Dumuria, Wazirpur, Subarnachar and Kalapara upazilas of Khulna, Barishal, Noakhali Patuakhali districts, respectively in the southern Bangladesh. The satellite images for GIS mapping were captured at vegetation stage of Boro-2018 and Aman-2018 during March-April and October-November. Technical performances of reaper and combine harvester were used to determine the required number harvester based on the estimated cultivated area found through GIS maps. The calculated required number of a) reaper, b) mini combine and c) medium combine to cover the estimated paddy area are a) 17 and 16, 1 and 5, 38 and 127, 6 and 21, b) 35 and 32, 3 and 10, 76 and 254, 13 and, 42 and c) 10 and 9, 1 and 3, 21 and 72, 4, and 12 during Boro and Aman seasons at Kulbaria-Baratia, Mundopasha, Charwabda and Holdibaria of Dumuria, Wazirpur, Subarnachar and Kalapara upazilas, respectively. The estimated results revealed that GIS tools and remote sensing are helping in simplification and visualization by incorporating data sets which can supports decision making for the implementation of paddy harvesting technologies in order to ensure the proper agricultural mechanization. Based on the accuracy assessment, GIS tool is found very useful to assess area to be harvested mechanically with specific type and number of harvester. It can be considered for formulating mechanized harvesting policy through further research in other areas.

Atmospheric pressure loading in GPS positions: dependency on GPS processing methods and effect on assessment of seasonal deformation in the contiguous USA and Alaska

The Global Positioning System (GPS) has revolutionized the ability to monitor Earth-system processes, including Earth’s water cycle. Several analysis centers process GPS data to estimate ground-antenna positions at daily temporal resolution. Differences in processing strategies can lead to inconsistencies in coordinate-position estimates and therefore influence the analysis of crustal displacement associated with variations in atmospheric and hydrologic mass loading. Here, we compare five GPS data products produced by three processing centers: the Nevada Geodetic Laboratory, Jet Propulsion Laboratory, and UNAVCO Consortium. We find that 5 to 30% of the scatter in residual GPS time series (commonly considered noise) can be explained by atmospheric loading in the contiguous USA and Alaska, but that the percentages vary widely by data product. Positions derived using high-resolution troposphere models (e.g., ECMWF) exhibit significantly lower scatter after correcting for atmospheric loading than positions estimated using constant or slowly varying troposphere models (e.g., GPT2w). The data products also exhibit differences in seasonal deformation (commonly attributed, in large part, to fluctuations in hydrologic mass loading): median vector differences in estimated seasonal amplitude range from 0.4–1.0 mm in the vertical component and 0.1–0.3 mm in the horizontal components, or about 10–40% of the mean amplitudes of seasonal oscillation. Newer products exhibit lower total scatter and stronger correlations than older products. Network-coherent differences in estimates of seasonal deformation reveal reference-frame inconsistencies between data products. We also cross-check two independent models of atmospheric pressure loading: ESMGFZ and LoadDef.

Effects of the High-Order Ionospheric Delay on GPS-Based Tropospheric Parameter Estimations in Turkey

The tropospheric delay and gradients can be estimated using Global Positioning System (GPS) observations after removing the ionospheric delay, which has been widely used for atmospheric studies and forecasting. However, high-order ionospheric (HOI) delays are generally ignored in GPS processing to estimate atmospheric parameters. In this study, HOI effects on GPS-estimated tropospheric delay and gradients are investigated from two weeks of GPS data in June 2011 at selected GPS stations in Turkey. Results show that HOI effects are up to 6 mm on zenith tropospheric delay (ZTD), 4 mm on the North-South (NS) gradient and 12 mm on the East-West (EW) gradient during this period, but can reach over 30 mm in slant tropospheric delays. Furthermore, the HOI effects on tropospheric delay and gradient are larger in the daytime than the nighttime. Furthermore, HOI effects on tropospheric delay are further investigated on low and high solar activity days. The HOI effects on GPS estimated tropospheric delay and gradients in high solar activity days are higher than those in low solar activity days.

Impact of GPS Processing on the Estimation of Snow Water Equivalent Using Refracted GPS Signals

Global navigation satellite system (GNSS) antennas buried underneath a snowpack have a high potential for in situ snow water equivalent (SWE) estimation. Automated and continuous SWE quantification independent of weather conditions could enhance snow hydrological monitoring and modeling. Accurate and reliable in situ data are needed for the calibration and validation of remote sensing data and snowpack modeling. A relative bias of less than 5% is achieved using sub-snow global positioning system (GPS) antennas (GPS refractometry) during a three full seasons time period in the Swiss Alps. A systematic overview regarding the temporal reliability of the sub-snow GPS derived results is, however, missing for this emerging technique. Moreover, GPS processing impacts the results significantly. Different GPS processing parameters are therefore selected and their influence on the SWE estimation is investigated. The impact of elevation-dependent weighting, the elevation cutoff angles, and the time intervals for SWE estimation are systematically assessed. The best results are achieved using all observations with an elevation-dependent weighting scheme. Moreover, the SWE estimation performance is equally accurate for hourly SWE estimation as for lower temporal resolutions up to daily estimates. The impact of snow on the coordinate solution is furthermore evaluated. While the east and north components are not systematically influenced by the overlying snowpack, the vertical component exhibits a significant variation and strongly depends on the SWE. The biased vertical component therefore provides an additional possibility to estimate SWE.

Potentially Misleading GPS Leveling–Based Assessment of Gravimetric Geoid or Quasigeoid Models due to Vertical Land Motion and Different GPS Processing Software

AbstractGravimetric geoid or quasigeoid models are often evaluated using Global Positioning System (GPS) and leveling, but the veracity of these control data is not always considered. Using a preci...

Interpretation of the Tropospheric Gradients Estimated With GPS During Hurricane Harvey

During the last decade Global Positioning System (GPS) Continuous Operating Reference Stations networks have become a new important data source for meteorology. This has dramatically improved the ability to remotely sense the atmosphere under the influence of severe mesoscale and synoptic systems. The zenith tropospheric delay (ZTD) is one of the atmospheric variables continuously observed, and its horizontal variations, the horizontal tropospheric gradients, are routinely computed nowadays within the dual‐frequency GPS processing, but their interpretation and relationship with the weather is still an open question. The purpose of this paper is to contribute in this direction by studying the effect that Hurricane Harvey had on the spatial and temporal behavior of the ZTDs and gradients, when it reached Texas coast, during 18–31 August 2017. The results show that ZTD time series present a clear and rapid increase larger than 10 cm in a few hours when the hurricane reached the area. Gradients behaviors show that the hurricane also produced significant changes on them, since the magnitude and predominant directions before and after the hurricane arrived are completely different. Noticeably, the gradient vectors before the landing are consistently related to the horizontal winds and pressure fields. In this manuscript we demonstrate that the ZTD gradients can show a consistent signature under severe weather events, strongly suggesting their potential application for short‐term weather forecasting.

Travel mode imputation using GPS and accelerometer data from a multi-day travel survey

Over the past decade, interest has grown in using Global Positioning System (GPS) data to augment or even to replace traditional travel survey or activity diaries. If the full potential of this new class of data is to be realized, processing techniques will need to be standardized and automated to some degree. This paper develops a multinomial logit (MNL) model to impute travel mode from GPS and hip-mounted accelerometer data. The MNL model is the workhorse of travel demand modeling, but it has rarely been applied to GPS data processing. A web-based recall survey provided over 900 trips for estimation and 500 plus trips for validation from a larger multi-day GPS travel survey in Portland, Oregon. Special attention is given to the imputation of bicycle travel, the identification of which has been given little attention in the North American context. We also apply two existing non-MNL mode imputation models to our Portland data and to compare and test the broader transferability of specific techniques. We find that the MNL model as specified performs well overall, generally outperforming competing model forms on the Portland GPS data. Transit network data and accelerometer data significantly improve model fit for specific modes. Accelerometer data is found in particular to aid model fit for bicycling; however, external validation results were less clear. No benefit is found to segmenting models by traveler age, although not all age groups were covered by the sample. The MNL model shows strong potential for automated GPS processing and, as a commonly used transportation modeling technique, should be relatively easy to implement elsewhere.

JARINGAN AD-HOC VEHICULAR (VANET) : TINJAUAN TENTANG ARSITEKTUR, KARAKTERISTIK, APLIKASI, DAN PROTOKOL MEDIUM ACCESS CONTROL (MAC)

VANET (Vehicular Ad-hoc Network) is an ad-hoc wireless network which nodes are composed by mostly moving vehicles and infrastructure communications or access points along the road. It integrates adhoc networking, cellular technology, wireless LAN and other technologies, which include GPS(Global Positioning System), digital mapping, sensing technologies and advanced information processing tools to support Intelligent Traffic Systems (ITS). VANET is developed mainly to improve road safety and to increase the traffic efficiency. It is designed to support the exchange of warning messages among the vehicles to increase the passenger safety and other information related to VANET applications and services . To achieve these goals, there are several issues that should be addressed. One of these challenges is designing reliable and efficient Medium Access Control (MAC) protocol for VANET. Due to VANET’s distinguishing characteristics, such as high mobility of the nodes, dynamic network topology, enough battery power, high processing power, etc, the MAC protocols designed for MANET (Mobile Ad-hoc Network) are not suitable for VANET. The research community has been working to develop MAC protocols appropriate for this ad-hoc network by proposing new design or modifying the existing one.In this paper, the VANET’s architecture, characteristics, applications and standard are discussed and then a comprehensive study of several MAC protocols available in the literature is presented.

An assessment of sub-snow GPS for quantification of snow water equivalent

Abstract. Global Navigation Satellite Systems (GNSS) contribute to various Earth observation applications. The present study investigates the potential and limitations of the Global Positioning System (GPS) to estimate in situ water equivalents of the snow cover (snow water equivalent, SWE) by using buried GPS antennas. GPS-derived SWE is estimated over three seasons (2015/16–2017/18) at a high Alpine test site in Switzerland. Results are validated against state-of-the-art reference sensors: snow scale, snow pillow, and manual observations. SWE is estimated with a high correspondence to the reference sensors for all three seasons. Results agree with a median relative bias below 10 % and are highly correlated to the mean of the three reference sensors. The sensitivity of the SWE quantification is assessed for different GPS ambiguity resolution techniques, as the results strongly depend on the GPS processing.

Spatially varying surface seasonal oscillations and 3-D crustal deformation of the Tibetan Plateau derived from GPS and GRACE data

Measurements of 189 continuous and 933 campaign-mode Global Positioning System (GPS) stations with 3–16 yr data spans over the Tibetan Plateau reveal contemporary three-dimensional (3-D) crustal deformation during 1999–2016. The Empirical Orthogonal Function method was used to characterize the spatial variations in the surface deformation with distinct seasonal oscillations at the GPS sites in five regions of the Tibetan Plateau. We find that these surface variations are highly correlated with the corresponding mass load signals observed by the Gravity Recovery and Climate Experiment (GRACE) mission. The improved GPS processing strategy used to determine the 3-D velocity field includes maximum likelihood estimation, removal of common mode errors from GPS time series using Principal Component Analysis (PCA), and power law plus white noise stochastic error modeling. We determined the rates of vertical crustal movement by removing GRACE-observed non-tectonic origin load deformation, 2002–2016. The corrected vertical crustal deformation shows that the Himalaya region is uplifting at an average rate of ∼1.7 mm yr−1, and that the northeastern Tibetan Plateau is uplifting at an average rate of ∼1.3 mm yr−1. In addition, the horizontal velocity relative to the stable Eurasian plate and its corresponding dilatation throughout the Tibetan Plateau suggest that tectonic shortening and crustal thickening is occurring at −90 to −80 nanostrain yr−1 in the southern Tibetan Plateau and −30 to −20 nanostrain yr−1 in the northeastern Tibetan Plateau, which could be related to the geologic shortening and elastic strain accumulation. The interior Tibetan Plateau exhibits crustal thinning and block movement along strike-slip faults. Eastward motion of the crust north of the Xianshuihe-Xiaojiang Fault system relative to crust to its south results in shear strain and reflects eastward escape of plastic crustal material in the southeastern Tibetan Plateau.

Global positioning system processing methods for GPS passive coherent location

This study addresses processing methods for the use of the global positioning system (GPS) as a signal of opportunity in a multistatic passive coherent location (PCL) system. The signal properties of the GPS signal are designed for position estimation, which makes it particularly suited for GPS PCL applications. The signal specifications are examined and the potential limitations of a proposed system are explored. Conventional GPS processing techniques are implemented in the framework of multistatic GPS PCL. GPS specific methods are developed for target position estimation of a multistatic PCL system in a three-dimensional plane. The PCL system has comparable performance metrics to conventional GPS positioning. Two methods are developed utilising measurements available in a conventional GPS system. The first involves a short time scale, which is in the order of milliseconds. The second involves a long time scale method, which is on the order of seconds. Simulation and analysis are performed to verify the methods. Experimental validation was also conducted using a hardware in the loop approach, as well as, an active radar calibrator.

Cost-effective monitoring of land subsidence in developing countries using semipermanent GPS stations: a test study over Houston, Texas

We present a cost-effective method for monitoring land subsidence in developing countries using measurements from semipermanent global positioning system (GPS) stations and interferometric synthetic aperture radar (InSAR) observations. The cost of maintaining a network of permanent GPS stations to monitor subsidence in developing countries might be implausible due to the high cost of maintenance. Hence, semipermanent GPS stations could be an alternative method, which densifies a GPS network with relatively inexpensive costs. We used three statistical methods to estimate the subsidence. We investigated the optimum time intervals for semipermanent GPS measurements based on the similarities of subsidence magnitudes and curve patterns with the permanent GPS measurements. In addition, we assessed the open source GPS processing tools based on the data quality of different session durations. Among the three models, the smoothing spline model showed the best estimation of subsidence. Among the different time interval data, 10- or 30-day time interval data were optimum for semipermanent GPS stations. Finally, we compared the GPS results to the InSAR-derived subsidence result, and both methods show that the northwestern Houston area subsides by about 1.5 to 2.0 cm/year. We anticipate that our method can be applied to other cities experiencing subsidence in developing countries.

Comparison of Various GPS Processing Solutions toward an Efficient Validation of the Hellenic Vertical Network: The ELEVATION Project

AbstractA research project called ELEVATION (Evaluation of the HelLEnic Vertical Network in the FrAme of the European SysTems and Control Networks InterconnectiON—Application in the Areas of Attica and Thessaloniki) for the validation of the Hellenic vertical network is currently in progress. Two investigation areas in central and northern Greece were chosen for the project. The areas include several benchmarks of the national trigonometric and leveling networks. In the current research, static global positioning system (GPS) observations as well as classical terrestrial leveling were performed to assess the internal accuracy of the two networks. This paper presents some of the numerical tests based on GPS and leveling measurements and outlines the goals of the project. The strategies followed in the processing of GPS data are presented, with emphasis on their future use within this project. GPS observations were processed using various commercial as well as scientific software packages to examine the inf...

Real-time retrieval of precipitable water vapor from GPS and BeiDou observations

The rapid development of the Chinese BeiDou Navigation Satellite System (BDS) brings a promising prospect for the real-time retrieval of zenith tropospheric delays (ZTD) and precipitable water vapor (PWV), which is of great benefit for supporting the time-critical meteorological applications such as nowcasting or severe weather event monitoring. In this study, we develop a real-time ZTD/PWV processing method based on Global Positioning System (GPS) and BDS observations. The performance of ZTD and PWV derived from BDS observations using real-time precise point positioning (PPP) technique is carefully investigated. The contribution of combining BDS and GPS for ZTD/PWV retrieving is evaluated as well. GPS and BDS observations of a half-year period for 40 globally distributed stations from the International GNSS Service Multi-GNSS Experiment and BeiDou Experiment Tracking Network are processed. The results show that the real-time BDS-only ZTD series agree well with the GPS-only ZTD series in general: the RMS values are about 11–16 mm (about 2–3 mm in PWV). Furthermore, the real-time ZTD derived from GPS-only, BDS-only, and GPS/BDS combined solutions are compared with those derived from the Very Long Baseline Interferometry. The comparisons show that the BDS can contribute to real-time meteorological applications, slightly less accurately than GPS. More accurate and reliable water vapor estimates, about 1.3–1.8 mm in PWV, can be obtained if the BDS observations are combined with the GPS observations in the real-time PPP data processing. The PWV comparisons with radiosondes further confirm the performance of BDS-derived real-time PWV and the benefit of adding BDS to standard GPS processing.

Crustal deformation on the Chinese mainland during 1998–2014 based on GPS data

This study focuses on resolving moderate amounts of crustal motion at the continental scale based on a large volume of global positioning system (GPS) data during 1998–2014. A state-of-the-art GPS processing strategy was used to resolve position time series and velocities from carrier beat phases for all available data. Position time series were closely analyzed to estimate linear constant, coseismic displacements, postseismic motions, and other parameters. We present coseismic offsets inferred from the GPS data for the 2010 Yushu and 2014 Yutian earthquakes, and also illustrate transient postseismic motions following the 2001 Kokoxili, 2008 Wenchuan, and 2011 Tohoku-Oki earthquakes. Since not all GPS position time series dominated by postseismic motions can be modeled and corrected reasonably, we present contemporary horizontal velocities from 2009 to 2014 for campaign stations and from 1998 to 2014 for continuous stations, irrespective of postseismic deformations. Our study concludes that we need to accumulate observations over a greater duration and apply accurate postseismic modeling to correct for transient displacement in order to resolve reasonable interseismic velocity.

Non-linear motions of Australian geodetic stations induced by non-tidal ocean loading and the passage of tropical cyclones

We investigate daily and sub-daily non-tidal oceanic and atmospheric loading (NTOAL) in the Australian region and put an upper bound on potential site motion examining the effects of tropical cyclone Yasi that crossed the Australian coast in January/February 2011. The dynamic nature of the ocean is important, particularly for northern Australia where the long-term scatter due to daily and sub-daily oceanic changes increases by 20–55 % compared to that estimated using the inverted barometer (IB) assumption. Correcting the daily Global Positioning System (GPS) time series for NTOAL employing either a dynamic ocean model or the IB assumption leads to a reduction of up to 52 % in the weighted scatter of daily coordinate estimates. Differences between the approaches are obscured by seasonal variations in the GPS precision along the northern coast. Two compensating signals during the cyclone require modelling at high spatial and temporal resolution: uplift induced by the atmospheric depression, and subsidence induced by storm surge. The latter dominates ( $$>$$ 135 %) the combined net effect that reaches a maximum of 14 mm, and 10 mm near the closest GPS site TOW2. Here, 96 % of the displacement is reached within 15 h due to the rapid transit of cyclones and the quasi-linear nature of the coastline. Consequently, estimating sub-daily NTOAL is necessary to properly account for such a signal that can be 3.5 times larger than its daily-averaged value. We were unable to detect the deformation signal in 2-hourly GPS processing and show that seasonal noise in the Austral summer dominates and precludes GPS detection of the cyclone-related subsidence.