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Journal ArticleDOI

3D building model-based pedestrian positioning method using GPS/GLONASS/QZSS and its reliability calculation

01 Jul 2016-Gps Solutions (Springer Berlin Heidelberg)-Vol. 20, Iss: 3, pp 413-428
TL;DR: A rectified positioning method using a basic three-dimensional city building model and ray-tracing simulation to mitigate the signal reflection effects is developed and successfully defines a positioning accuracy based on the distribution of the candidates and their pseudorange similarity.
Abstract: The current low-cost global navigation satellite systems (GNSS) receiver cannot calculate satisfactory positioning results for pedestrian applications in urban areas with dense buildings due to multipath and non-line-of-sight effects. We develop a rectified positioning method using a basic three-dimensional city building model and ray-tracing simulation to mitigate the signal reflection effects. This proposed method is achieved by implementing a particle filter to distribute possible position candidates. The likelihood of each candidate is evaluated based on the similarity between the pseudorange measurement and simulated pseudorange of the candidate. Finally, the expectation of all the candidates is the rectified positioning of the proposed map method. The proposed method will serve as one sensor of an integrated system in the future. For this purpose, we successfully define a positioning accuracy based on the distribution of the candidates and their pseudorange similarity. The real data are recorded at an urban canyon environment in the Chiyoda district of Tokyo using a commercial grade u-blox GNSS receiver. Both static and dynamic tests were performed. With the aid of GLONASS and QZSS, it is shown that the proposed method can achieve a 4.4-m 1ź positioning error in the tested urban canyon area.
Citations
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Journal ArticleDOI
TL;DR: This study demonstrates that 3D city models are employed in at least 29 use cases that are a part of more than 100 applications that could be useful for scientists as well as stakeholders in the geospatial industry.
Abstract: In the last decades, 3D city models appear to have been predominantly used for visualisation; however, today they are being increasingly employed in a number of domains and for a large range of tasks beyond visualisation. In this paper, we seek to understand and document the state of the art regarding the utilisation of 3D city models across multiple domains based on a comprehensive literature study including hundreds of research papers, technical reports and online resources. A challenge in a study such as ours is that the ways in which 3D city models are used cannot be readily listed due to fuzziness, terminological ambiguity, unclear added-value of 3D geoinformation in some instances, and absence of technical information. To address this challenge, we delineate a hierarchical terminology (spatial operations, use cases, applications), and develop a theoretical reasoning to segment and categorise the diverse uses of 3D city models. Following this framework, we provide a list of identified use cases of 3D city models (with a description of each), and their applications. Our study demonstrates that 3D city models are employed in at least 29 use cases that are a part of more than 100 applications. The classified inventory could be useful for scientists as well as stakeholders in the geospatial industry, such as companies and national mapping agencies, as it may serve as a reference document to better position their operations, design product portfolios, and to better understand the market.

547 citations

Journal ArticleDOI
TL;DR: This paper proposes to employ an innovative GNSS positioning technique with the aid of a 3-D building map in the integration of the Global Navigation Satellite System (GNSS) and onboard inertial sensor integration in a Kalman filter framework.
Abstract: Lane-level vehicle self-localization is a challenging and significant issue arising in autonomous driving and driver-assistance systems. The Global Navigation Satellite System (GNSS) and onboard inertial sensor integration are among the solutions for vehicle self-localization. However, as the main source in the integration, GNSS positioning performance is severely degraded in urban canyons because of the effects of multipath and non-line-of-sight (NLOS) propagations. These GNSS positioning errors also decrease the performance of the integration. To reduce the negative effects caused by GNSS positioning error, this paper proposes to employ an innovative GNSS positioning technique with the aid of a 3-D building map in the integration. The GNSS positioning result is used as an observation, and this is integrated with the information from the onboard inertial sensor and vehicle speedometer in a Kalman filter framework. To achieve stable performance, this paper proposes to evaluate and consider the accuracy of the employed GNSS positioning method in dynamic integration. A series of experiments in different scenarios is conducted in an urban canyon, which can demonstrate the effectiveness of the proposed method using various evaluation and comparison processes.

111 citations


Cites methods from "3D building model-based pedestrian ..."

  • ...Moreover, the GLObal NAvigation Satellite System (GLONASS) and Quasi-Zenith Satellite System (QZSS) were introduced to the 3-D-buildingmap-based method for pedestrian application [24]....

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Journal ArticleDOI
TL;DR: An algorithm to detect NLOS signals from the pseudorange measurements by using a 3D building model, ray-tracing simulation, and known receiver position is developed and an innovative NLOS model using two variables, the elevation angle and the distance between the receiver and building that reflect the NLOS is proposed.
Abstract: Current GPS positioning accuracy in urban areas is still unsatisfactory for various applications, including pedestrian navigation and autonomous driving. Due to the ineffectiveness of special corrector designs against non-line-of-sight (NLOS) reception, the research regarding NLOS signals has been increasing in the recent years. This study first develops an algorithm to detect NLOS signals from the pseudorange measurements by using a 3D building model, ray-tracing simulation, and known receiver position. According to the analysis of 24 h of collected NLOS data, a new finding is that NLOS pseudorange delay is highly correlated with the elevation angle of satellite instead of the received signal strength. Thus, we further propose an innovative NLOS model using two variables, the elevation angle and the distance between the receiver and building that reflect the NLOS. The proposed model is evaluated in both pseudorange and position domains. Based on the experiment results regarding pseudorange error, the difference between the proposed model and the collected NLOS measurement is very small. Finally, the proposed model is applied to a hypothesis-based positioning method and achieves about 6.3 m in terms of horizontal positioning accuracy, which is only slightly worse than the method applied with ray-tracing simulation.

104 citations

Journal ArticleDOI
01 Jan 2020
TL;DR: To improve the accuracy of signal reception classification, the three features of C/N0, pseudorange residuals and satellite elevation angle are used with a gradient boosting decision tree (GBDT) based classification algorithm.
Abstract: In urban areas, GPS signals are often reflected or blocked by buildings, which causes multipath effects and non-line-of-sight (NLOS) reception respectively consequently degrading GPS positioning performance. While improved receiver design can reduce the effect of multipath to some extent, it cannot deal with NLOS. Modelling methods based on measurements have shown promise to reduce the effect of NLOS signal reception. However, this depends on their ability to accurately and reliably classify line-of-sight (LOS), multipath and NLOS signals. The traditional method is based on one feature using signal strength as measured by the carrier to noise ratio, C/N0. However, this feature is ineffective in capturing the characteristics of multipath and NLOS in all environments. In this paper, to improve the accuracy of signal reception classification, we are using the three features of C/N0, pseudorange residuals and satellite elevation angle with a gradient boosting decision tree (GBDT) based classification algorithm. Experiments are carried out to compare the proposed algorithm with classifiers based on decision tree, distance weighted k-nearest neighbour (KNN) and the adaptive network-based fuzzy inference system (ANFIS). Test results from static receivers in urban environments, show that the GBDT based algorithm achieves a classification accuracy of 100%, 82% and 86% for LOS, multipath and NLOS signals, respectively. This is superior to the other three algorithms with the corresponding results of 100%, 82% and 84% for the Distance-Weighted KNN, 99%, 70% and 65% for the ANFIS and 98%, 35% and 95% for the traditional decision tree. With the NLOS detection and exclusion, the proposed GBDT with multi-feature based method can provide a positioning accuracy improvement of 34.1% compared to the traditional C/N0 based method.

94 citations

Journal ArticleDOI
TL;DR: This paper proposes to apply a fish-eye camera to capture the sky view image to further classify the NLOS and line-of-sight (LOS) measurements, and shows that the proposed method could effectively mitigate the effects of GNSS outliers, and an improved accuracy was obtained, when compared with the conventional GNSS/INS integration.
Abstract: GNSS/INS integrated solution has been extensively studied over the past decades. However, its performance relies heavily on environmental conditions and sensor costs. The GNSS positioning can obtain satisfactory performance in the open area. Unfortunately, its accuracy can be severely degraded in a highly urbanized area, due to the notorious multipath effects and none-line-of-sight (NLOS) receptions. As a result, excessive GNSS outliers occur, which causes a huge error in GNSS/INS integration. This paper proposes to apply a fish-eye camera to capture the sky view image to further classify the NLOS and line-of-sight (LOS) measurements. In addition, the raw INS and GNSS measurements are tightly integrated using a state-of-the-art probabilistic factor graph model. Instead of excluding the NLOS receptions, this paper makes use of both the NLOS and LOS measurements by treating them with different weightings. Experiments conducted in typical urban canyons of Hong Kong showed that the proposed method could effectively mitigate the effects of GNSS outliers, and an improved accuracy of GNSS/INS integration was obtained, when compared with the conventional GNSS/INS integration.

93 citations

References
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Journal ArticleDOI
TL;DR: This paper presents the derivation of these narrow correlator spacing improvements, verified by simulated and tested performance.
Abstract: Historically, conventional GPS receivers have used 1.0 chip early-late correlator spacing in the implementation of delay lock loop s (DLLs), However, there are distinct advantages to narrowing this spacing, especially in C/A-code tracking applications. These advantages are the reduction of tracking errors in the presence of both noise and multipath. The primary disadvantage i s that a wider precorrelation bandwidth is required, coupled with higher sample rates and higher digital signal processing rates. However, with current CMOS technology, this is easily achievable and well worth the price. Noise reduction is achieved with narrower spacing because the noise components of the early and late signals are correlated and ten d to cancel, provided that early and late processing are simultaneous (not dithered). Multipath effects are reduced because the DLL discriminator is less distorted by the delayed multipath signal. This paper presents the derivation of these narrow correlator spacing improvements, verified by simulated and tested performance.

749 citations


"3D building model-based pedestrian ..." refers background in this paper

  • ...Conventionally, the multipath mitigation techniques can be divided into two categories: antenna design (Braasch 1996; McGraw et al. 2004) and receiver-based correlator design (Dierendonck et al. 1992; Garin et al. 1996)....

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  • ...2004) and receiver-based correlator design (Dierendonck et al. 1992; Garin et al. 1996)....

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Journal ArticleDOI
TL;DR: A comprehensive review of the propagation prediction models for terrestrial wireless communication systems is presented and the focus is placed on the application of ray-tracing techniques to the development of deterministic propagation models.
Abstract: A comprehensive review of the propagation prediction models for terrestrial wireless communication systems is presented in this paper. The classic empirical models are briefly described and the focus is placed on the application of ray-tracing techniques to the development of deterministic propagation models. Schemes to increase the computational efficiency and accuracy are discussed. Traditional statistical models are also briefly reviewed for completeness. New challenges to the propagation prediction are described and some new approaches for meeting these challenges are presented.

563 citations


"3D building model-based pedestrian ..." refers methods in this paper

  • ...The ray-tracing used is described in Iskander and Zhengqing (2002)....

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Journal ArticleDOI

407 citations


"3D building model-based pedestrian ..." refers background in this paper

  • ...The symbol rq denotes the user equivalent range error (UERE) (Groves 2013)....

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  • ...We follow the same idea of conventional GPS rule of thumb, which is GPS accuracy = DOP 9 UERE (Kaplan et al. 2006)....

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  • ...The UERE of the 3D map method is estimated from the mean of pseudorange similarities of all candidates....

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  • ...The discriminator will greatly reduce the multipath effect because it reduces the pull-in region of the code delay (Groves 2013)....

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  • ...However, the calculation of user-equivalent range error (UERE) and dilution of precision (DOP) of the proposed method are revised based on the difference between the simulated and measured pseudorange and the distribution of valid particles, respectively....

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Journal ArticleDOI
TL;DR: Three different techniques for mitigating the impact of non-line-of-sight (NLOS) reception and multipath interference on position accuracy without using additional hardware are investigated, testing them using data collected at multiple sites in central London.
Abstract: Multiple global navigation satellite system (GNSS) constellations can dramatically improve the signal availability in dense urban environments. However, accuracy remains a challenge because buildings block, reflect and diffract the signals. This paper investigates three different techniques for mitigating the impact of non-line-of-sight (NLOS) reception and multipath interference on position accuracy without using additional hardware, testing them using data collected at multiple sites in central London. Aiding the position solution using a terrain height database was found to have the biggest impact, improving the horizontal accuracy by 35% and the vertical accuracy by a factor of 4. An 8% improvement in horizontal accuracy was also obtained from weighting the GNSS measurements in the position solution according to the carrier-power-to-noise-density ratio (C/N0). Consistency checking using a conventional sequential elimination technique was found to degrade horizontal positioning performance by 60% because it often eliminated the wrong measurements in cases when multiple signals were affected by NLOS reception or strong multipath interference. A new consistency checking method that compares subsets of measurements performed better, but was still equally likely to improve or degrade the accuracy. This was partly because removing a poor measurement can result in adverse signal geometry, degrading the position accuracy. Based on this, several ways of improving the reliability of consistency checking are proposed.

175 citations


"3D building model-based pedestrian ..." refers background in this paper

  • ...Consistency checking can also be used to identify both NLOS and multipath-contaminated signals (Groves and Jiang 2013)....

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