Robust GNSS Positioning in Urban Environments

GNSSmultipathNLOSintegrityurban canyon

Multipath and NLOS interference is not a corner case — it is the default in dense cities.

Our work focuses on:

NLOS and multipath detection and mitigation
Non-Gaussian measurement modeling
GNSS integrity monitoring for safety-critical applications

Related Publications

journal

3D LiDAR Aided GNSS NLOS Correction by Direction-of-Arrival Estimation Using Doppler Measurements in Urban Canyons

Liu X, Wen W, Zhang L, Hsu L. T

IEEE Transactions on Intelligent Transportation Systems (2025)

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journal

3D LiDAR Aided GNSS NLOS Mitigation in Urban Canyons

Wen W. and Hsu L. -T

IEEE Transactions on Intelligent Transportation Systems (2022)

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journal Featured

3D Mapping Database Aided GNSS RTK and Its Assessments in Urban Canyons

Ng H.F, Hsu L.T

IEEE Transactions on Aerospace and Electronic Systems (2021)

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journal

3D Point Clouds Data Super Resolution Aided LiDAR Odometry for Vehicular Positioning in Urban Canyons

Yue J, Wen W, Han J, Hsu L. T

IEEE Transactions on Vehicular Technology (2021)

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patent

3d vision aided gnss real-time kinematic positioning for autonomous systems in urban canyons

Hsu L. T, Wen W

Patent (2023)

journal

3D Vision Aided GNSS Real-Time Kinematic Positioning for Autonomous Systems in Urban Canyons

Wen W, Bai X, Hsu L. T

NAVIGATION: Journal of the Institute of Navigation (2023)

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conference

3DMA GNSS Positioning with Multipath Signals in Urban Areas: Methodology and Preliminary Results

Mingda Ye, Guohao Zhang, Li-Ta Hsu

ION GNSS+, The International Technical Meeting of the Satellite Division of The Institute of Navigation (2024)

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journal

A Computation Effective Range-Based 3D Mapping Aided GNSS with NLOS Correction Method

Ng H. F, Zhang G, Hsu L. T

Journal of Navigation (2020)

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journal

A Framework for Graphical GNSS Multipath and NLOS Mitigation

Xu P, Zhang G, Zhong Y, Yang B, Hsu L. T

IEEE Transactions on Intelligent Transportation Systems (2024)

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journal

A New Path Planning Algorithm Using GNSS Localization Error Map for UAV in Urban Area

Zhang G, Hsu L.T

Journal of Intelligent & Robotic Systems (2018)

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journal

A Probabilistic Approach to Detect and Mitigate GNSS NLOS Using State Augmented Kalman Filter

Jiang C, Xu B, Hsu L. T

GPS Solutions (2021)

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conference

An Adaptive Weighted GNSS/VINS/Wi-Fi RTT-based Seamless Positioning System for Smartphone

Meiling Su, Bing Wang, Sugata Ahad, Xinyue Huang, Guohao Zhang, Li-Ta Hsu

2024 14th International Conference on Indoor Positioning and Indoor Navigation (IPIN) (2024)

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journal

Analysis and Modelling GPS NLOS effect in Highly Urbanized Area

Hsu L. T

GPS Solutions (2018)

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journal

Assessment of beamforming for GNSS multipath mitigation with a cost-effective structure

Jia Q, Hsu L. T, Xu B, Wu R

Journal of Navigation (2020)

conference

AutoW: Self-Supervision Learning for Weighting Estimation in GNSS Positioning

Penghui Xu, Li-Ta Hsu

ION GNSS+, The International Technical Meeting of the Satellite Division of The Institute of Navigation (2024)

DOI

conference

Bounding the Heavy-Tailed Pseudorange Error by Leveraging Membership Weights Analysis of Gaussian Mixture Model

Penggao Yan, Yihan Zhong, Li-Ta Hsu

ION Pacific PNT (2024)

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journal

C/N0 Assessment Based on GPS L5/L1C/A Signal Acquisition in Open-Sky/Light-Urban/Dense-Urban/Indoor Environments with Extended Coherent Integration Time

Tsang C. L, Luo Y, Xu B, Hsu L. T

Journal of Aeronautics, Astronautics and Aviation (2023)

conference

Certifiably Optimal Satellite Orbit Determination Based on Doppler Measurements for Low-Earth-Orbit Satellites

Baoshan Song, Weisong Wen, Li-Ta Hsu

2025 IEEE/ION Position, Location and Navigation Symposium (PLANS) (2025)

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journal

Characterization and Validation of GNSS Multipath-Induced Doppler Measurement Error

Fang J, Zhang L, Zhang G, Xu B, Hsu L. T

IEEE Transactions on Aerospace and Electronic Systems (2024)

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journal

Coarse-to-Fine Loosely-Coupled LiDAR-Inertial Odometry for Urban Positioning and Mapping

Zhang J, Wen W, Huang F, Hsu L. T

Remote Sensing (2021)

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journal

Correcting NLOS by 3D LiDAR and building height to improve GNSS single point positioning

Wen W, Zhang G, Hsu L. T

Navigation, Journal of Institute of Navigation (2019)

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journal

Degeneration-aware Outlier Mitigation for Visual Inertial Integrated Navigation System in Urban Canyons

Bai X, Wen W, Hsu L. T

IEEE Transactions on Instrumentation and Measurement (2021)

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conference

DGNSS Corrected Pseudorange and Time-Differenced Carrier Phase (TDCP) Measurements using Differentiable Factor Graph Optimization (DFGO)

Hoi-Fung Ng, Penghui Xu, Yihan Zhong, Guohao Zhang, Weisong Wen, Li-Ta Hsu

ION GNSS+, The International Technical Meeting of the Satellite Division of The Institute of Navigation (2024)

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journal

Dynamic Object-aware LiDAR Odometry Aided by Joint Weightings Estimation in Urban Areas

Huang F, Wen W, Zhang J, Wang C, Hsu L. T

IEEE Transactions on Intelligent Vehicles (2023)

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journal

Enhancing GNSS Positioning Accuracy for Road Monitoring Systems: A Factor Graph Optimization Approach Aided by Geospatial Information

Zhong Y, Hu R, Bai X, Li X, Hsu L. T, Wen W

IEEE Transactions on Instrumentation and Measurement (2024)

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journal

Evaluation of Multi-GNSSs and GPS with 3D Map Methods for Pedestrian Positioning in an Urban Canyon Environment

Hsu L. T, Chen F, Kamijo S

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences (2015)

DOI

conference

Exploring the Feasibility of Automated Data Standardization using Large Language Models for Seamless Positioning

Max J. L. Lee, Ju Lin, Li-Ta Hsu

2024 14th International Conference on Indoor Positioning and Indoor Navigation (IPIN) (2024)

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journal

Extending Shadow Matching to Tightly-Coupled GNSS/INS Integration System

Zhang G, Wen W. Xu B, Hsu L. T

IEEE Transactions on Vehicular Technology (2020)

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conference

Factor Graph Optimization Based Multi Epoch Ambiguity Resolution for GNSS RTK and its Evaluation in Hong Kong Urban Canyons

Yuan Li, Xikun Liu, Weisong Wen, Li-Ta Hsu, Yilong Yuan, Guangyu Bian, Qiaoyun Chen

ION GNSS+, The International Technical Meeting of the Satellite Division of The Institute of Navigation (2024)

DOI

journal

Factor Graph Optimization-based GNSS PPP-RTK: An Alternative Platform to Study Urban GNSS Precise Positioning

Xin S, Geng J, Hsu L. T

IEEE Transactions on Aerospace and Electronic Systems (2024)

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journal Featured

GLIO: Tightly-coupled gnss/lidar/imu integration for continuous and drift-free state estimation of intelligent vehicles in urban areas

Liu X, Wen W, Hsu L. T

IEEE Transactions on Intelligent Vehicles (2023)

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journal

GNSS direct position estimation-inspired positioning with pseudorange correlogram for urban navigation

Vicenzo S, Xu B, Xu H, Hsu L. T

GPS Solutions (2024)

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conference

GNSS Measurement Performance in Vegetation Environments: Assessment and Analysis in Signal Processing Level

Di Hai, Chin Lok Tsang, Guohao Zhang, Li-Ta Hsu

ION GNSS+, The International Technical Meeting of the Satellite Division of The Institute of Navigation (2024)

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journal

GNSS NLOS Exclusion Based on Dynamic Object Detection Using LiDAR Point Cloud

Wen W, Zhang G, Hsu L. T

IEEE Transactions on Intelligent Transportation Systems (2019)

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journal

GNSS RUMS: GNSS Realistic Urban Multi-agent Simulator for Collaborative Positioning Research

Zhang G, Xu B, Ng H.F, Hsu L. T

Remote Sensing (2021)

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journal

GNSS-RTK Adaptively Integrated with LiDAR/IMU Odometry for Continuously Global Positioning in Urban Canyons

Zhang J, Wen W, Huang F, Wang Y, Chen X, Hsu L. T

Applied Sciences (2022)

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conference

GNSS/Map Integration with Batch Factor Graph Optimization for Reliable Trajectory Estimation in Urban Canyon

Yihan Zhong, Hoi-Fung Ng, Li-Ta Hsu, Weisong Wen

2025 IEEE/ION Position, Location and Navigation Symposium (PLANS) (2025)

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journal

GNSS/On-Board Inertial Sensor Integration with the Aid of 3D Building Map for Lane-Level Vehicle Self-Localization in Urban Canyon

Gu Y, Hsu L. T, Kamijo S

IEEE Transactions on Vehicular Technology (2016)

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journal

GNSS/Visual/IMU/Map Integration Via Sliding Window Factor Graph Optimization for Vehicular Positioning in Urban Areas

Bai X, Hsu L. T

IEEE Transactions on Intelligent Vehicles (2024)

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journal Featured

Hong Kong UrbanNav: An open-source multisensory dataset for benchmarking urban navigation algorithms

Hsu L. T, Huang F, Ng H. F, Zhang G, Zhong Y, Bai X, Wen W

NAVIGATION: Journal of the Institute of Navigation (2023)

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journal

Improved Weighting Scheme using Consumer-level GNSS L5/E5a/B2a Pseudorange Measurements in the Urban Area

Ng H.F, Zhang G, Yang K.Y, Yang S. X. Hsu L. T

Advances in Space Research (2020)

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conference

Improving GNSS Positioning in Challenging Urban Areas by Digital Twin Database Correction

Jiarong Lian, Jiayi Zhou, Yiran Luo, Guohao Zhang, Li-Ta Hsu

2024 14th International Conference on Indoor Positioning and Indoor Navigation (IPIN) (2024)

DOI

journal

Improving GPS Code Phase Positioning Accuracy in Urban Environments Using Machine Learning

Sun R, Wang G, Cheng Q, Fu L, Chiang K.W, Hsu L. T. and Ochieng W. Y

IEEE Internet of Things Journal (2020)

DOI

journal

Integrating Global Navigation Satellite System and Road-Marking Detection for Vehicle Localization in Urban Traffic

Gu Y, Hsu L. T, Bao J, Kamijo S

Transportation Research Record Journal (2016)

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journal

Integration of GNSS and BLE Technology With Inertial Sensors for Real-Time Positioning in Urban Environments

Luo H, Li Y, Wang J, Weng D, Ye J, Hsu L. T, Chen W

IEEE Access (2021)

DOI

journal

Integrity Monitoring of multi-GNSS SPP and DGNSS in Urban Environment using ARAIM and 3D City Models

El-Mowafy A, Xu B, Hsu L. T

Journal of Spatial Science (2020)

journal

Integrity-Constrained Factor Graph Optimization for GNSS Positioning in Urban Canyons

Xia X, Wen W, Hsu L. T

NAVIGATION: Journal of the Institute of Navigation (2024)

DOI

journal

Intelligent GPS L1 LOS/Multipath/NLOS Classifiers Based on Correlator-, RINEX-and NMEA-Level Measurements

Xu B, Jia Q, Luo Y, Hsu L. T

Remote Sensing (2019)

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journal

Low‐cost solid‐state LiDAR/inertial‐based localization with prior map for autonomous systems in urban scenarios

Zhong Y, Huang F, Zhang J, Wen W, Hsu L. T

IET Intelligent Transport Systems (2023)

DOI

conference

Machine Learning Assisted GNSS Direct Position Estimation for Urban Environments Applications

Sergio Vicenzo, Xin Qi, Bing Xu, Li-Ta Hsu

The International Technical Meeting of the The Institute of Navigation (2024)

DOI

journal

Machine Learning based LOS/NLOS Classifier and Robust Estimator for GNSS Shadow Matching

Xu H, Angrisano A, Gaglione S, Hsu L. T

Satellite Navigation (2020)

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journal

Machine Learning in GNSS Multipath/NLOS Mitigation: Review and Benchmark

Xu P, Zhang G, Yang B, Hsu L. T

IEEE Aerospace and Electronic Systems Magazine (2024)

DOI

conference

Modeling and Validation of GNSS Multipath-Induced Doppler Tracking Error

Jingxiaotao Fang, Liyuan Zhang, Guohao Zhang, Bing Xu, Li-Ta Hsu

The International Technical Meeting of the The Institute of Navigation (2024)

DOI

journal

Multi-Agent Collaborative GNSS/Camera/INS Integration Aided by Inter-ranging for Vehicular Navigation in Urban Areas

Wen W, Bai X, Zhang G, Chen S, Yuan F, Hsu L. T

IEEE Access (2020)

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journal

Multipath mitigation and NLOS detection using vector tracking in urban”

Hsu L. T, Jan S. S, Groves P. D, Kubo N

GPS Solutions (2014)

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journal

Multipath Mitigation Technique under Strong Multipath Environment Using Multiple Antennas

Kubo N, Kobayashi. K, Hsu L.T, Amai O

Journal of Aeronautics, Astronautics and Aviation, Series A (2017)

journal

Multiple Faults Isolation For Multi-Constellation GNSS Positioning through Incremental Expansion of Consistent Measurements

Yan P, Hu Y, Wen W, Hsu L. T

IEEE Sensors Journal (2025)

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journal

Multiple Faulty GNSS Measurement Exclusion based on Consistency Check in Urban Canyons

Hsu L. T, Tokura H, Kubo N, Gu Y, Kamijo S

IEEE Sensors Journals (2017)

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journal

NLOS Correction/Exclusion for GNSS Measurement using RAIM and City Building Models

Hsu L. T, Gu Y, Kamijo S

Sensors (2015)

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journal

Object Detection Aided GNSS and Its Integration with LiDAR in Highly Urbanized Areas

Wen W, Zhang G, Hsu L. T

IEEE Intelligent Transportation Systems Magazine (2020)

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journal

Passive Sensor Integration for Vehicle Self-Localization in Urban Traffic Environment

Gu Y, Hsu L. T, Kamijo S

Sensors (2015)

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journal

Performance Assessment of the GNSS Diffraction Models in Urban Areas

Zhang G, Hsu L. T

Navigation, Journal of Institute of Navigation (2021)

DOI

journal Featured

PositionNet: CNN-based GNSS positioning in urban areas with residual maps

Xu P, Zhang G, Yang B, Hsu L. T

Applied Soft Computing (2023)

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journal

Prediction on the Urban GNSS Measurement Uncertainty based on Deep Learning Networks with Long Short-Term Memory

Zhang G, Xu P, Xu H, Hsu L. T

IEEE Sensors Journal (2021)

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journal

Random forest-based multipath parameter estimation

Qi X, Xu B, Wang Z, Hsu L. T

GPS Solutions (2024)

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journal

Rectification of GNSS based Collaborative Positioning using 3D Building Models in Urban Areas

Zhang G, Wen W, Hsu L. T

GPS Solutions (2019)

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conference

Roadside GNSS Aided Multi-Sensor Integrated System for Vehicle Positioning in Urban Areas

Feng Huang, Yihan Zhong, Hang Chen, Dongzhe Su, Jin Wu, Weisong Wen, Li-Ta Hsu

2025 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (2025)

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journal Featured

Robust GNSS Shadow Matching for Smartphones in Urban Canyons

Ng H.F, Zhang G, Hsu L. T

IEEE Sensors Journal (2021)

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journal

Robust Visual-Inertial Integrated Navigation System Aided by Online Sensor Model Adaption for Autonomous Ground Vehicles in Urban Areas

Bai X, Wen W, Hsu L. T

Remote Sensing (2020)

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journal

Safety-Quantifiable Planar-Feature-based LiDAR Localization with a Prior Map for Intelligent Vehicles in Urban Scenarios

Zhang J, Liu X, Wen W, Hsu L. T

IEEE Transactions on Intelligent Vehicles (2024)

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journal

Scalar and vector tracking loop simulation based on a uniform semi-analytic model and robustness analysis in multipath/NLOS situations. GPS Solutions 26(97)

Jia Q, Hsu L. T, Wu R

(2022)

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journal

Semantic-Based VPS for Smartphone Localization in Challenging Urban Environments

Lee J.L. M, Hsu L. T, Ng H.-F

Sensors (2021)

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journal

Skymask Matching Aided Positioning Using Sky-Pointing Fisheye Camera and 3D City Models in Urban Canyons

Lee M.J.L, Lee S, Ng H. F, Hsu L T

Sensors (2020)

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journal

Subspace-based Adaptive GMM Error Modeling for Fault-Aware Pseudorange-based Positioning in Urban Canyons

Yan P, Xia X, Brizzi M, Wen W, Hsu L. T

IEEE Transactions on Intelligent Vehicles (2024)

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journal

Three-Dimensional Mapping-Aided Global Navigation Satellite System in Global Navigation Satellite System-Accessible Indoor Areas

Hoi-Wah Ng, Hoi-Fung Ng, Li-Ta Hsu, John-Ross Rizzo

Sensors (2026)

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journal

Bai X, Wen W, Hsu L. T

IEEE Transactions on Aerospace and Electronic Systems (2022)

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journal

Towards lane-level traffic monitoring in urban environment using precise probe vehicle data derived from three-dimensional map aided differential GNSS

Gu Y, Hsu L.T, Kamijo S

IATSS Research (2018)

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journal

Trajectory Smoothing Using GNSS/PDR Integration Via Factor Graph Optimization in Urban Canyons

Zhong Y, Wen W, Hsu L. T

IEEE Internet of Things Journal (2024)

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journal

Urban Building Updates Monitoring Based on Sky Visibility Estimation From Satellite Signals

Xu H, Zhang G, Hsu L. T

IEEE Internet of Things Journal (2024)

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journal

Urban Pedestrian Navigation using Smartphone-based Dead Reckoning and 3D Maps Aided GNSS

Hsu L. T, Gu Y, Huang Y, Kamijo S

IEEE Sensors Journal (2016)

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journal

Urban Positioning: 3D Mapping Aided GNSS using Dual-Frequency Pseudorange Measurements from Smartphones

Ng H.F, Zhang G, Hsu L. T

Navigation, Journal of Institute of Navigation (2021)

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journal

Using Dual-Polarization GPS Antenna with Optimized Adaptive Neuro-Fuzzy Inference System to Improve Single Point Positioning Accuracy in Urban Canyons

Sun R, Fu L, Wang G, Cheng Q, Hsu L. T. and Ochieng W. Y

Navigation, Journal of Institute of Navigation (2020)

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journal

Using Sky-Pointing Fish-eye Camera and LiDAR to Aid GNSS Single Point Positioning in Urban Canyons

Bai X, Wen W, Hsu L. T

IET Intelligent Transport Systems (2020)

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journal

Vector Tracking Loop-based GNSS NLOS Detection and Correction: Algorithm Design and Performance Analysis

Xu B, Jia Q. and Hsu L. T

IEEE Transactions on Instrumentation and Measurement (2019)

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magazine

What are the roles of artificial intelligence and machine learning in GNSS positioning

Hsu L. T

Inside GNSS (2020)

journal

Wind dynamic and energy-efficiency path planning for unmanned aerial vehicles in the lower-level airspace and urban air mobility context

Chan Y. Y, Ng K. K, Lee C. K. M, Hsu L. T, Keung K. L

Sustainable Energy Technologies and Assessments (2023)

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