المؤلفون: Lu, Yi, Wei, Dongyan, Yuan, Hong

المصدر: Applied Sciences (2076-3417); Apr2024, Vol. 14 Issue 7, p3079, 20p

مصطلحات موضوعية: TRANSFORMER models, GLOBAL Positioning System, FEATURE extraction, VEHICLE routing problem, MAGNETIC levitation vehicles, DATABASES, LOCALIZATION (Mathematics)

مستخلص: Magnetic positioning is a promising technique for vehicles in Global Navigation Satellite System (GNSS)-denied scenarios. Traditional magnetic positioning methods resolve the position coordinates by calculating the similarity between the measured sequence and the sequence generated from the magnetic database with criteria such as the Mean Absolute Difference (MAD), PRODuct correlation (PROD), etc., which usually suffer from a high mismatch rate. To solve this problem, we propose a novel magnetic localization method for vehicles based on Transformer. In this paper, we cast the magnetic localization problem as a regression task, in which a neural network is trained by equidistant sequences to predict the current position. In addition, by adopting Transformer to perform magnetic localization of vehicles for the first time, magnetic features are extracted, and positional relationships are explored to guarantee positioning accuracy. The experimental results show that the proposed method can greatly improve the magnetic positioning accuracy, with an average improvement of approximately 2 m. [ABSTRACT FROM AUTHOR]

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المؤلفون: Lu, Yi, Wei, Dongyan, Li, Wen, Ji, Xinchun, Yuan, Hong

المصدر: Electronics (2079-9292); Apr2024, Vol. 13 Issue 7, p1315, 21p

مصطلحات موضوعية: GLOBAL Positioning System, MAGNETIC levitation vehicles, DATABASES

مستخلص: Magnetic positioning is a promising technique for vehicles in global navigation satellite system (GNSS)-denied scenarios. In general, a fixed-length magnetic sequence is required to provide an initial positioning result, which means that users need to wait a relatively long distance. To minimize this initialization distance, a map-aided fast initialization method, including magnetic database construction and magnetic positioning, is proposed in this paper. For magnetic database construction, a multisource fused database is established using a precise and effective strategy in which the positions of reference points (RPs) and the diverse information of paths are obtained from the map and the magnetic field is calculated using data collected during driving. For magnetic positioning, we innovatively propose a coarse–fine combination method that improves the positioning accuracy within a short distance. In the coarse map matching stage, by detecting the vehicle's motion and utilizing the topological relationships between paths, the search range is precisely narrowed. In the fine magnetic localization stage, an improved mean absolute difference (MAD) metric and a derivative metric are combined to form a joint matching criterion to determine the positioning result. The experimental results illustrate the importance of each module in the proposed method, which improves the precision of the database up to 80% and significantly shortens the initialization distance up to 50%. [ABSTRACT FROM AUTHOR]

: Copyright of Electronics (2079-9292) is the property of MDPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Wang, Zhiyu, Wang, Liang, Li, Zishen, Hoque, Mainul, Wang, Ningbo, Wei, Dongyan, Yuan, Hong

المصدر: IET Radar, Sonar & Navigation (Wiley-Blackwell); Aug2023, Vol. 17 Issue 8, p1213-1229, 17p

مصطلحات موضوعية: ORBIT determination, ORBITS of artificial satellites, GLOBAL Positioning System, ORBITS (Astronomy), ARTIFICIAL satellites in navigation

مستخلص: The code multipath error associated with elevation in BDS‐2 is one of the main factors whose impact on the precision of real‐time reduced‐dynamic precise orbit determination (POD) using spaceborne multi‐global navigation satellite systems (GNSS) observation data for FengYun‐3C (FY‐3C) and FengYun‐3D (FY‐3D) satellites. The aim is to construct a code multipath piece‐wise linear error model and analyse the contribution of BDS‐2 to the performance of low earth orbit POD. Conclusions are drawn out from the experimental results: (1) the real‐time POD average precision of FY‐3C and FY‐3D is improved by about 11% and 12% after the correction of BDS‐2 code multipath error; (2) Due to the small number of available BDS‐2 satellites and the limited accuracy of geostationary earth orbit (GEO) satellite real‐time orbit products, the precision of the real‐time overlapping comparison for FY‐3C/FY‐3D by using the BDS‐2 onboard observation data can only reach the decimetre level. However, with the BDS‐2 signal capture capability of the FY‐3D onboard GNSS Occultation Sounder upgraded, the average precision of the BDS‐2‐based POD for FY‐3D is better than that of FY‐3C in each direction and with 10% improvement in the average 3 dimensional‐root mean square (3D‐RMS); (3) Cases of onboard global positioning system (GPS), GPS + BDS‐2 (with GEO), and GPS + BDS‐2 (without GEO) for real‐time POD can meet 5–8 cm precision requirement. The average 3D‐RMS of the real‐time POD for FY‐3C/FY‐3D, which utilises onboard GPS + BDS‐2 data is inferior only to GPS data, owing to the influence of the orbit accuracy of GEO satellites. However, after excluding the influence of GEO satellites, the average result (3D‐RMS) of the real‐time POD for FY‐3C (6.11 cm) and FY‐3D (5.95 cm) is better than those of other cases. [ABSTRACT FROM AUTHOR]

: Copyright of IET Radar, Sonar & Navigation (Wiley-Blackwell) is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Li, Xianghong^1,2, Wei, Dongyan¹, Lai, Qifeng¹, Xu, Ying¹ nadinexy@aoe.ac.cn, Yuan, Hong¹

المصدر: Advances in Space Research. Feb2017, Vol. 59 Issue 3, p877-887. 11p.

مصطلحات موضوعية: *GLOBAL Positioning System, *BLUETOOTH technology, *PEDESTRIANS, *MAGNETOMETERS, *GYROSCOPES

مستخلص: Typical indoor location method is fingerprint and traditional outdoor location system is GPS. Both of them are of poor accuracy and limited only for indoor or outdoor environments. As the smartphones are equipped with MEMS sensors, it means PDR can be widely used. In this paper, an algorithm of smartphone-based integrated PDR/GPS/Bluetooth for pedestrian location in the indoor/outdoor is proposed, which can be highly expected to realize seamless indoor/outdoor localization of the pedestrian. In addition, we also provide technologies to estimate orientation with Magnetometer and Gyroscope and detect context with output of sensors. The extensive experimental results show that the proposed algorithm can realize seamless indoor/outdoor localization. [ABSTRACT FROM AUTHOR]

المؤلفون: Lai, Qifeng, Yuan, Hong, Wei, Dongyan, Wang, Ningbo, Li, Zishen, Ji, Xinchun

المصدر: Sensors (14248220); May2020, Vol. 20 Issue 9, p2551, 1p

مصطلحات موضوعية: MULTISENSOR data fusion, GLOBAL Positioning System, INERTIAL navigation systems, TELECOMMUNICATION satellites

مستخلص: Using the Global Navigation Satellite System (GNSS), it is difficult to provide continuous and reliable position service for vehicle navigation in complex urban environments, due to the natural vulnerability of the GNSS signal. With the rapid development of the sensor technology and the reduction in their costs, the positioning performance of GNSS is expected to be significantly improved by fusing multi-sensors. In order to improve the continuity and reliability of the vehicle navigation system, we proposed a multi-sensor tight fusion (MTF) method by combining the inertial navigation system (INS), odometer, and barometric altimeter with the GNSS technique. Different fusion strategies were presented in the open-sky, insufficient satellite, and satellite outage environments to check the performance improvement of the proposed method. The simulation and real-device tests demonstrate that in the open-sky context, the error of sensors can be estimated correctly. This is useful for sensor noise compensation and position accuracy improvement, when GNSS is unavailable. In the insufficient satellite context (6 min), with the help of the barometric altimeter and a clock model, the accuracy of the method can be close to that in the open-sky context. In the satellite outage context, the error divergence of the MTF is obviously slower than the traditional GNSS/INS tightly coupled integration, as seen by odometer and barometric altimeter assisting. [ABSTRACT FROM AUTHOR]

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المؤلفون: Wei, Dongyan¹ (AUTHOR) weidy@aircas.ac.cn, Huang, Lichen^1,2 (AUTHOR) huanglichen17@mails.ucas.ac.cn, Ji, Xinchun^1,2 (AUTHOR), Li, Wen^1,2 (AUTHOR), Lu, Yi^1,2 (AUTHOR), Yuan, Hong¹ (AUTHOR)

المصدر: Sensors (14248220). 12/15/2019, Vol. 19 Issue 24, p5410. 1p.

مصطلحات موضوعية: *GLOBAL Positioning System

مستخلص: Magnetic navigation is a promising positioning technique for scenarios where a global navigation satellite system (GNSS) is unavailable, such as for underwater submarines and aircraft in space. For ground scenarios, it faces more challenges, since the magnetic distribution suffers interference from surrounding objects such as buildings, bridges, and vehicles. It is natural to think how feasible it is to apply magnetic matching positioning to vehicles. In this paper, a theoretic distribution model is proposed to analyze the magnetic field around objects such as buildings, bridges, and vehicles. According to the experiments, it is shown that the proposed model matches the experimental data well. In addition, a comprehensive indicator metric is defined in this paper to describe the feasibility of the magnetic matching method based on the statistical characteristics of magnetic maps. The best length of matching window, anti-noise performance, and pre-comparison of positioning accuracy in different regions can be easily derived using the proposed comprehensive indicator metric. Finally, the metric is verified through a drive test using different building densities. [ABSTRACT FROM AUTHOR]