Accuracy Of GPS Positioning Research Articles

Optimization of Map Matching Algorithm in Various Road Conditions

Map matching refers to find the real driving trajectory of the vehicle by its GPS data. To solve this problem, most research focuses on improving the accuracy of GPS positioning. Even so, map matching still has a large deviation in complex road sections, such as interchanges, underground tunnels and other areas with high spatial complexity. At the same time, traditional map matching algorithms, such as hidden Markov model (HMM) and nearest neighbor algorithms, have the disadvantage of long running time. Different from the research on improving the accuracy of positioning, this research focuses on optimizing and creating a new algorithm for map matching. In order to solve the accuracy of map matching under complex road conditions, this paper adds a new attribute of altitude to GPS data for the first time, and greatly improves the accuracy of map matching in complex road conditions by constructing a three-dimensional hidden Markov model (3D HMM). In order to reduce the running time of the algorithm, this paper uses graph convolutional neural network as a bridge, integrates a variety of map matching algorithms and constructs a hybrid algorithm. Through experiments, it is found that the running time and accuracy of this hybrid algorithm are better than other algorithms.

Comparison of L1 and L5 GPS smartphone absolute positioning results

Abstract The paper presents the analysis of single-point GPS positioning results obtained from smartphones, using code observations on the L1 and L5 frequencies. In this research we used two Huawei P30 Pro mobile phones and one geodetic receiver (Javad Alpha) acting as the reference receiver. Smartphones were placed at an equal distance of 0.5 m from this receiver. Such a close distance was specially planned by the authors in order to achieve identical observation conditions. Thus, it was possible to compare the accuracy of GPS positioning using pseudoranges on the L1 and L5 frequencies for individual observation epochs. The analysis was carried out from static GPS positioning, using the results from the open-source RTKLib software. In general, the usefulness of code measurements on the L5 frequency to determine the GPS position made it possible to increase the accuracy by several times with respect to the positions determined using the C/A code on the L1 frequency. Average errors of horizontal and vertical coordinates were about 70 % lower for the GPS solution using the L5 code observations than using the L1 code observations. Based on statistical analysis, a horizontal accuracy of about 0.45 m and vertical accuracy of about 1.8 m (STDEV) with only five GPS satellites may be obtained using a smartphone with L5 code observations.

ACCURACY ANALYSIS OF AIRCRAFT POSITIONING USING GPS DUAL RECEIVERS IN AERIAL NAVIGATION

This study presents a modified algorithm to determine the accuracy of GPS positioning in aerial navigation. To achieve this, a mixed model with measurement weights was used to determine the resultant value of accuracy of aerial vehicle positioning. The measurement weights were calculated as a function of the number of GPS tracking satellites. The calculations were performed on actual GPS measurement data recorded by two onboard GNSS receivers installed onboard a Cessna 172 aircraft. The flight test was conducted around the military airport in Dęblin. The conducted analyses demonstrated that the developed algorithm improved the accuracy of GPS positioning from 62 to 91% for horizontal coordinates and between 16-83% for the vertical component of the aerial vehicle position in the BLh ellipsoidal frame. The obtained test results show that the developed method improves the accuracy of aircraft position and could be applied in aerial navigation.

Dual Receiver EGNOS+SDCM Positioning with C1C and C1W Pseudo-Range Measurements

The paper presents an approach to the simultaneous use of SDCM and EGNOS corrections for two GNSS receivers placed at a constant distance. The SDCM and EGNOS corrections were applied for two GPS code measurements on L1 frequency: C1C and C1W. The approach is based mainly on the constrained least squares adjustment, but for the horizontal and vertical coordinates, the Kalman Filter was applied in order to reduce pseudo-range noises. It allows for obtaining a higher autonomous accuracy of GPS/(SDCM+EGNOS) positioning than when using only the GPS/EGNOS or GPS/SDCM system. The final dual-redundant solution, in which two SBAS systems were used (EGNOS+SDCM) and two GPS pseudo-ranges (C1C+C1W) were present, yielded RMS errors of 0.11 m for the horizontal coordinates and 0.25 m for the vertical coordinates. Moreover, the accuracy analysis in the developed mathematical model for the determined 3D coordinates with simultaneous use of EGNOS and SDCM systems proved to be much more reliable than using only a single EGNOS or SDCM system. The presented approach can be used not only for precise navigation, but also for some geoscience applications and remote sensing where the reliable accuracy of autonomous GPS positioning is required.

EFFECT OF USING DIFFERENT SATELLITE EPHEMERIDES ON GPS PPP AND POST PROCESSING TECHNIQUES

The orbital error is one of the errors in GPS which affect the accuracy of GPS positioning. In this research GPS broadcast, ultra-rapid, rapid and precise satellite ephemerides are used for processing different baseline lengths among some CORS stations by using the Trimble Business Center software (TBC) and different satellite ephemerides (NRCan ultra-rapid, NRCan rapid and IGS final) are tested in CSRS-PPP online application at the same CORS stations. In this research, when using TBC software for processing the different baseline lengths by using the different satellite ephemerides and compared the coordinates of CORS stations which obtained from the different satellite ephemerides with each other. The results showed that the best satellite ephemerides closest to rapid and final satellite ephemerides are the ultra-rapid (00 UTC) and ultra-rapid (06 UTC). When processing the same CORS stations which used at TBC on CSRSPPP online application by using the different satellite ephemerides it is found also that the NRCan ultra-rapid closest to final satellite ephemerides.

Accuracy of GPS positioning concerning Köppen-Geiger climate classification

Recent studies revealed the effect of meteorological seasons on the accuracy of GPS positioning. The existing accuracy model is weak because it is derived from a climate classification in which the earth is divided into latitudinal zones, and each climate zone in the classification does not have sufficient number of International GNSS Service (IGS) sites as representative. Furthermore, the prediction is biased due to the loading effects and tectonic motion. Here, we will derive a new accuracy model using the climate zone classification of Köppen and Geiger, which is based on actual meteorological measurements. Fifty IGS stations almost homogenously covering the Köppen-Geiger geographical regions and the globe have been selected, and the data has been analyzed using Gipsy-X software. Using the new model, the average improvement in the accuracy prediction of the north, east, and up components is 50%, 68%, and 94%, respectively.

CONSIDERING VARIANCES OF QUASI-RANDOM EFFECTS IN RELATIVE GPS POSITIONING PERFORMED DURING DAYTIME AND NIGHTTIME PERIODS – A NOVEL TWO-STAGE APPROACH

In this paper, a new two-stage approach, involving an integral treatement of all quasi-random effects limiting the accuracy of relative GPS positioning and the method of moments to obtain final variance components regarding the effects of short-term (“far-field”) multipath (factor b), joint action of long-term (“near-field”) multipath and receiver antenna phase center offset and variations (factor a1), as well as joint action of tropospheric and ionospheric refraction (factor a2), is presented. In the study, GPS data collected on five baselines were used. Variance components of the quasirandom effects were obtained for the three relative GPS coordinates (e, n and u) using individually monthly datsets including daytime- and those including nighttime-wise ambiguity-fixed baseline solutions. The related results show that statistically significant inequality exists when comparing corresponding variances obtained for daytime and nighttime periods. It turned out that the following standard deviation estimates intervals are present (by the coordinates e, n and u, respectively): (a) daytime period: 3.3–6.9, 4.6–9.0 and 9.1–20.3 mm (factor b); 1.5–4.7, 1.9–7.0 and 3.4–21.9 mm (factor 1a ); 0.0116– 0.3282, 0.0103–0.2365 and 0.1222–0.7818 mm/km (factor a2); (b) nighttime period: 3.2–4.9, 4.7–7.3 and 8.4–15.4 mm (factor b); 0.8–3.8, 2.1–5.0 and 3.1–15.8 mm (factor a1); 0.0118–0.2734, 0.0097–0.2289 and 0.0752–0.6315 mm/km (factor a2).

Enhancement of GPS Position Accuracy Using Machine Vision and Deep Learning Techniques

The accuracy of GPS position estimation in urban cities is an issue which need to be resolved using machine vision and deep learning techniques. The accuracy of GPS in horizontal direction is better than in the vertical direction. Although for most of the navigation applications in intelligent transportation systems, horizontal positioning accuracy is vital, but vertical position accuracy gives idea about road slanting conditions. Several statistical methods like median filtering, homomorphic filtering and k-means clustering, etc., can be used to improve upon the position accuracy of GPS signals. Such methods are useful for offline applications where a lot many GPS measurements are taken at a single point and afterwards filtering is applied to batch of measurement. In this study, the GPS positioning errors which are caused by sensor noise, ionospheric effects, occlusions by building facades, etc., have been considered for online improvement in position estimation using computer vision and deep learning methods by empirically choosing hyper-parameters.

Beidou-GPS dual mode positioning of mobile communication equipment based on Android platform

With the rapid development of science and technology, positioning technology has been widely used in people’s daily lives and related scientific research activities. However, the traditional positioning system mostly uses GPS for positioning, and then transmits the positioning information to the remote server through GPRS / GSM, but it is not applicable in remote mountain areas where some base station signals cannot reach. Moreover, the accuracy of single GPS positioning is difficult to be guaranteed. This paper mainly studies the design of Beidou-GPS dual-mode positioning system based on Android platform mobile communication equipment. First, analyse the composition of the satellite positioning system and design the overall architecture of the Beidou-GPS dual-mode positioning system for mobile communication equipment. Then, it analyses the most important star selection algorithm in dual-mode positioning technology, and proposes an improved star selection algorithm based on azimuth. Second, build the overall architecture of the Android platform for mobile communication devices based on dual-mode positioning. Finally, by comparing with the traditional star selection algorithm, the proposed improved positioning algorithm is experimentally verified. Simulation experiment results show that the proposed dual-mode positioning algorithm has high accuracy and can meet the real-time requirements of the system.

Effect of meteorological seasons on the accuracy of GPS positioning

GPS users need to know about the accuracy of the position and velocity information produced by the technique. The positioning accuracy of the technique depends mainly on observing session duration. The accuracy of GPS was previously studied using samples of 10–30 consecutive days. Namely, the effect of seasons was not taken into consideration. For instance, an annual cycle plays crucial role on GPS vertical rates. In order to quantify the global disturbance on positioning due to seasonal differences, here we designed a GPS experiment using the stations of International GNSS Service (IGS). GPS data were sampled from a two-year range not from several days. The data were processed using GIPSY/OASIS II. The results show that the RMS is greater at the equatorial regions. The new prediction of the accuracy becomes poorer especially for 8–24 h sessions. In addition, the traditional accuracy formulation needs to be expanded including one additional term.

Positioning Error in Mobile Phone Tracking Data with Consideration of Geographic Environment Factors

Abstract. Summary. This research contributes to both theory and application. This is an important supplement to the research on the quality and uncertainty of spatial big data and it will help mobile phone data play a more effective application value in future research. In recent years, the rapid development of data acquisition means has led to the rapid accumulation of spatial data and generated spatial big data with geographic location information. However, the uncertainty in spatial big data leads to the quality problem of spatial big data, which is one of the main bottlenecks restricting the effective utilization of spatial big data. As an important part of spatial big data, it is necessary to study the quality and uncertainty of mobile phone data. In view of this, we delve into the key geographical environment factors that affect the positioning error of mobile phone data, extract error evaluation indexes and construct the spatial distribution model of positioning error with machine learning algorithms. To explore the distribution law of mobile phone data positioning error under different geographical scenarios. In addition, considering the high accuracy of personal travel GPS positioning, this study takes personal travel GPS positioning data as the comparative object of mobile phone data for analysis.

Evaluation on the performance of single and dual frequency low cost GPS module observation using geodetic antenna

GPS modules have been used for various applications in recent years. Its early development came in parallel with the advancement of Unmanned Aerial Vehicle (UAV) technology. Nowadays, it is also used in in geographic information system (GIS) data acquisition/census, mapping surveys, structure stability monitoring systems and many other applications. GPS modules generally have several positioning features, including standard positioning service (SPS), static positioning, precise point positioning (PPP), post processing kinematic (PPK) and real time kinematic (RTK) GPS. GPS modules in general are only equipped with a microstrip-type antenna or better known as patch antenna. Results from related research show that GPS module with this type of antenna has sub meter accuracy when used for PPK or RTK GPS method. The use of geodetic antennas is very potential to increase GPS position accuracy by up to centimeter level. This paper discusses the evaluation of GPS module measurements with geodetic type antennas for precise positioning using RTK GPS. This paper is focused on the resolution of GPS cycle ambiguity that is often expressed by the term fixing ratio and the accuracy of measurement results obtained. To provide a comprehensive description of the performance of GPS module, in this research two types of GPS module were used; single and dual frequency. Both types of GPS modules were used to conduct simultaneous observation on an open and obstructed observation location.

도심에서 수직구조물 랜드마크를 이용한 3D LIDAR 기반 차량정밀측위

Tall buildings in urban areas obstruct the GPS satellite signal reception, thus the GPS position accuracy can be very poor. However, buildings in urban areas can be used to generate a landmark map for precise vehicle localization. This map’s information can be represented in various forms. We focused on the outer wall of a building that was erected vertically from the ground and almost flat. Therefore, vertical corners that meet the vertical planes are present everywhere in urban areas. These corners can provide very good landmarks and can be extracted using LIDAR. Additionally, traffic signs can be used for localization. The traffic signs are present in the road and reflect light well. Therefore, traffic signs can be clearly distinguished from other structures using LIDAR reflectivity. In this paper, we used building’s vertical corner and traffic signs for vehicle localization in an urban area. In addition, we proposed a vertical structure map with information for vertical corners and traffic signs. The experiment was carried out in the Gangnam area of Seoul, South Korea. The traveling distance was approximately 4.5 km and the maximum traveling speed was approximately 80 km/h. The lateral and longitudinal RMS position errors were 0.118 m and 0.231 m, respectively.

지도 정보를 활용한 저사양 GPS의 위치 정확도 향상 기법

지도 정보를 활용한 저사양 GPS의 위치 정확도 향상 기법

Business model analysis of mobile traffic safety services

Purpose The aim of this paper is to identify promoting and restraining factors of a novel mobile service in the pedestrian safety area. Design/methodology/approach This paper uses the case study methodology that focus on analyzing a specific case of mobile safety services in depth. A case study is especially suitable for an emerging case, such as pedestrian safety, where the aim is to identify relevant influencing factors of the particular case and not to generalize the findings. To gather data for case study analysis, several expert interviews were performed. Because they provided a large volume of data, the Service, Technology, Organization, and Finance business model framework was used as a way of structuring the analysis. Findings The main restraining factors are end-user value proposition, battery life, accuracy of GPS positioning and the revenue model. However, the service could improve traffic safety considerably and it should be introduced first locally in places, where many accidents take place. There is a great interest on driver data, which could be the main advantage for this service in the future. Integration to navigation products would complement the service significantly. Originality/value Current traffic safety-related literature covers mainly technical issues, and there are only few papers related to business model issues on that particular service. Observations of the various factors affecting the related evolution at an early phase of the life-cycle support further service design process.

Wavelets and triple difference as a mathematical method for filtering and mitigation of DGPS errors

The accuracy of GPS position is primarily dependent on the satellite position, signal delay, and various environment noises such as ionospheric delay effects, ephemeris errors, satellite clock errors, multi-path distortion, tropospheric delay effects, and numerical errors. To overcome most of these errors the Differential Global Positioning System (DGPS) is used. Differential Global Positioning System is one of the most popular and reliable techniques for improving GPS accuracy by minimizing correlated errors between reference stations and rovers. The primary motivation of this paper is to improve GPS measurement accuracies by classifying errors in the frequency domain and subsequently separating, mitigating and decreasing them.Wavelet spectral techniques can separate GPS signals into sub-bands where different errors can be separated and mitigated. The main goal of this paper was the development and implementation of DGPS error mitigation techniques using triple difference and wavelet. This paper studies, analyzes and provides new techniques that will help mitigate these errors in the frequency domain. The proposed technique applied to smooth noise for GPS receiver positioning data is based upon the analysis of wavelet transform (WT). The technique is applied using wavelet as a de-noising tool to tackle the high-frequency errors in the triple difference domain and to obtain a de-noised triple difference signal that can be used in a positioning calculation.

Performance Analysis of L2 and L5 CNAV Broadcast Ephemeris for Orbit Calculation

Ephemeris error is a limiting factor in GPS position accuracy. The newly introduced GPS Civil Navigation (CNAV) broadcast message, an upgraded version of the legacy NAV message, is designed to provide users with more precise satellite orbit and timing parameters. A CNAV broadcast test was conducted in 2013 on the L2C and L5 bands. Since April 2014, pre-operational CNAV started to broadcast to civilian users. Baseband civil GPS signals on L1, L2, and L5 were recorded during the broadcast test and the pre-operational broadcast using wideband software radio front ends. The signals were acquired and tracked, with navigation messages decoded by the conventional Viterbi method and a computationally efficient matrix-based method. GPS ephemerides were extracted from the messages to compute satellite orbit solutions. This paper evaluates the orbit solution of both CNAV and Legacy NAV during the same time period to demonstrate the improvements in the CNAV ephemeris accuracy. Copyright © 2015 Institute of Navigation.

Effects of transionospheric signal decorrelation on Global Navigation Satellite Systems (GNSS) performance studied from irregularity dynamics around the northern crest of the EIA

AbstractTransionospheric satellite navigation links operate primarily at L band and are frequently subject to severe degradation of performances arising out of ionospheric irregularities. Various characteristic features of equatorial ionospheric irregularity bubbles like the drift velocity, characteristic velocity, decorrelation time, and decorrelation distance can be determined using spaced aerial measurements at VHF. These parameters measured at VHF from a station Calcutta situated near the northern crest of the Equatorial Ionization Anomaly (EIA) in the geophysically sensitive Indian longitude sector have been correlated with L band scintillation indices and GPS position accuracy parameters for identifying possible proxies to L band scintillations. Good correspondences have been observed between decorrelation times and distances at VHF with GPS S4 and Position Dilution of Precision during periods of GPS scintillations (S4 > 0.3) for February–April 2011, August–October 2011, and February–April 2012. A functional relation has been developed between irregularity drift velocity measured at VHF and S4 at L band during February–April 2011, and validation of measured S4 and predicted values performed during August–October 2011 and February–April 2012. Significant improvement in L band scintillation prediction and consequent navigational accuracy will result using such relations derived from VHF irregularity measurements which are much simpler and inexpensive.

Modeling GPS multipath effect based on spherical cap harmonic analysis

Most GPS positioning errors can be eliminated or removed by the differential technique or the modeling method, but the multipath effect is a special kind of system or gross error, so it is difficult to be simulated or eliminated. In order to improve the accuracy of GPS positioning, the single-epoch pseudorange multipath effects at GPS station were calculated, and firstly modeled based on the spherical cap harmonic (SCH), which is the function of satellite longitude and latitude with the robust method. The accuracy of the kinematic point positioning technique was improved by correcting pseudorange observations with the multipath effect calculated by the SCH model, especially in the elevation direction. The spherical cap harmonic can be used to model the pseudorange multipath effect.

Applying QFD and Kano Model to Experience Design for Cultural Tourism on Mobile Device: An Example of Leifeng Pagoda, Hangzhou, China

For most cultural landscapes, experience design is particular important. However, there is less research on experience design for cultural attractions. Whats more, some mobile Apps for cultural tourism are lack of good user experience. This paper proposes utilizing a combination of the Quality Function Deployment (QFD), Kano model and scenario-based design as a useful tool to design a mobile application for Leifeng pagoda tourism. The study makes clear the design directions. Results show that: (1) In regard to the culture of Leifeng pagoda, we should focus on introducing the pagoda history and sites; Information query of surrounding traffic, catering, accommodation is essential to tourists; the basic information guide is the most important need.(2) In the 18 design requirements, controls design, navigation design, information architecture are closely related to the software usability, so they have the highest priority; We should also pay attention to text content design, especially pagoda culture, and accuracy of GPS position.