Multi-Constellation GNSS Performance Evaluation for Urban Canyons Using Large Virtual Reality City Models
TL;DR: In this paper, the authors used 3D building models to predict satellite visibility in urban canyons and evaluated the performance of current and future GNSS in London with decimetre-level accuracy.
Abstract: Positioning using the Global Positioning System (GPS) is unreliable in dense urban areas with tall buildings and/or narrow streets, known as ‘urban canyons’. This is because the buildings block, reflect or diffract the signals from many of the satellites. This paper investigates the use of 3-Dimensional (3-D) building models to predict satellite visibility. To predict Global Navigation Satellite System (GNSS) performance using 3-D building models, a simulation has been developed. A few optimized methods to improve the efficiency of the simulation for real-time purposes were implemented. Diffraction effects of satellite signals were considered to improve accuracy. The simulation is validated using real-world GPS and GLObal NAvigation Satellite System (GLONASS) observations.
The performance of current and future GNSS in urban canyons is then assessed by simulation using an architectural city model of London with decimetre-level accuracy. GNSS availability, integrity and precision is evaluated over pedestrian and vehicle routes within city canyons using different combinations of GNSS constellations. The results show that using GPS and GLONASS together cannot guarantee 24-hour reliable positioning in urban canyons. However, with the addition of Galileo and Compass, currently under construction, reliable GNSS performance can be obtained at most, but not all, of the locations in the test scenarios. The modelling also demonstrates that GNSS availability is poorer for pedestrians than for vehicles and verifies that cross-street positioning errors are typically larger than along-street due to the geometrical constraints imposed by the buildings. For many applications, this modelling technique could also be used to predict the best route through a city at a given time, or the best time to perform GNSS positioning at a given location.
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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
TL;DR: An overview of the past and current literature discussing the GNSS integrity for urban transport applications is provided so as to point out possible challenges faced by GNSS receivers in such scenario.
Abstract: Integrity is one criteria to evaluate GNSS performance, which was first introduced in the aviation field. It is a measure of trust which can be placed in the correctness of the information supplied by the total system. In recent years, many GNSS-based applications emerge in the urban environment including liability critical ones, so the concept of integrity attracts more and more attention from urban GNSS users. However, the algorithms developed for the aerospace domain cannot be introduced directly to the GNSS land applications. This is because a high data redundancy exists in the aviation domain and the hypothesis that only one failure occurs at a time is made, which is not the case for the urban users. The main objective of this paper is to provide an overview of the past and current literature discussing the GNSS integrity for urban transport applications so as to point out possible challenges faced by GNSS receivers in such scenario. Key differences between integrity monitoring scheme in aviation domain and urban transport field are addressed. And this paper also points out several open research issues in this field.
265 citations
Cites background from "Multi-Constellation GNSS Performanc..."
...However, the urban environment presents great challenges to common commercial GNSS receivers [8], [9]....
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TL;DR: This paper investigates the performance improvements enabled by the tight integration, using low-cost sensors and a mass-market GNSS receiver and describes the developed tight-integration algorithms with a terse mathematical model and assesses their efficacy from a practical perspective.
Abstract: Global Navigation Satellite Systems (GNSSs) remain the principal mean of positioning in many applications and systems, but in several types of environment, the performance of standalone receivers is degraded. Although many works show the benefits of the integration between GNSS and Inertial Navigation Systems (INSs), tightly-coupled architectures are mainly implemented in professional devices and are based on high-grade Inertial Measurement Units (IMUs). This paper investigates the performance improvements enabled by the tight integration, using low-cost sensors and a mass-market GNSS receiver. Performance is assessed through a series of tests carried out in real urban scenarios and is compared against commercial modules, operating in standalone mode or featuring loosely-coupled integrations. The paper describes the developed tight-integration algorithms with a terse mathematical model and assesses their efficacy from a practical perspective.
146 citations
Cites background from "Multi-Constellation GNSS Performanc..."
...Second, the position accuracy of standalone receivers can be improved with innovative signal processing, such as high sensitivity tracking loops [10], Cooperative Positioning [11], or 3-Dimensional (3-D) building models to predict satellite visibility, as proposed in [12,13]....
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TL;DR: It is shown that vehicle kinematics allow the removal of external accelerations from the lateral and vertical axis accelerometer measurements, thus giving the correct estimate of lateral and Vertical axis gravitational accelerations.
Abstract: This paper presents a novel Kalman filter for the accurate determination of a vehicle’s attitude (pitch and roll angles) using a low-cost MEMS inertial measurement unit (IMU) sensor, comprising a tri-axial gyroscope and a tri-axial accelerometer. Currently, vehicles deploy expensive gyroscopes for attitude determination. A low-cost MEMS gyro cannot be used because of the drift problem. Typically, an accelerometer is used to correct this drift by measuring the attitude from gravitational acceleration. This is, however, not possible in vehicular applications, because accelerometer measurements are corrupted by external accelerations produced due to vehicle movements. In this paper, we show that vehicle kinematics allow the removal of external accelerations from the lateral and vertical axis accelerometer measurements, thus giving the correct estimate of lateral and vertical axis gravitational accelerations. An estimate of the longitudinal axis gravitational acceleration can then be obtained by using the vector norm property of gravitational acceleration. A Kalman filter is designed, which implements the proposed solution and uses the accelerometer in conjunction with the gyroscope to accurately determine the attitude of a vehicle. Hence, this paper enables the use of extremely low-cost MEMS IMU for accurate attitude determination in vehicular domain for the first time. The proposed filter was tested by both simulations and experiments under various dynamic conditions and results were compared with five existing methods from the literature. The proposed filter was able to maintain sub-degree estimation accuracy even under very severe and prolonged dynamic conditions. To signify the importance of the achieved accuracy in determining accurate attitude, we investigated its use in two vehicular applications: vehicle yaw estimate and vehicle location estimate by dead reckoning and showed the performance improvements obtained by the proposed filter.
125 citations
Cites background from "Multi-Constellation GNSS Performanc..."
...The Global Positioning System (GPS) is not a viable option due to this requirement, as it suffers from signal outage in urban areas, parking lots and tunnels etc [13], [14]....
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TL;DR: In this article, shadow matching has been adapted to work on an Android smartphone and presented the first comprehensive performance assessment of smartphone GNSS shadow matching, which significantly improves cross-street positioning accuracy in dense urban environments.
Abstract: Global Navigation Satellite System (GNSS) shadow matching is a new positioning technique that determines position by comparing the measured signal availability and strength with predictions made using a three-dimensional (3D) city model. It complements conventional GNSS positioning and can significantly improve cross-street positioning accuracy in dense urban environments. This paper describes how shadow matching has been adapted to work on an Android smartphone and presents the first comprehensive performance assessment of smartphone GNSS shadow matching. Using GPS and GLONASS data recorded at 20 locations within central London, it is shown that shadow matching significantly outperforms conventional GNSS positioning in the cross-street direction. The success rate for obtaining a cross-street position accuracy within 5 m, enabling the correct side of a street to be determined, was 54·50% using shadow matching, compared to 24·77% for the conventional GNSS position. The likely performance of four-constellation shadow matching is predicted, the feasibility of a large-scale implementation of shadow matching is assessed, and some methods for improving performance are proposed. A further contribution is a signal-to-noise ratio analysis of the direct line-of-sight and non-line-of-sight signals received on a smartphone in a dense urban environment.
116 citations
Cites background or methods from "Multi-Constellation GNSS Performanc..."
...The poor performance of Global Navigation Satellite Systems (GNSS) positioning in dense urban areas is a well-known problem (Wang et al., 2012)....
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...The elevation of the building boundary is computed at a range of azimuths as described in Wang et al. (2013a) and Wang et al. (2012)....
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References
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Book•
31 Dec 2007
TL;DR: In this paper, the authors present a single-source reference for navigation systems engineering, providing both an introduction to overall systems operation and an in-depth treatment of architecture, design, and component integration.
Abstract: Navigation systems engineering is a red-hot area. More and more technical professionals are entering the field and looking for practical, up-to-date engineering know-how. This single-source reference answers the call, providing both an introduction to overall systems operation and an in-depth treatment of architecture, design, and component integration. This book explains how satellite, on-board, and other navigation technologies operate, and it gives practitioners insight into performance issues such as processing chains and error sources. Providing solutions to systems designers and engineers, the book describes and compares different integration architectures, and explains how to diagnose errors. Moreover, this hands-on book includes appendices filled with terminology and equations for quick referencing.
1,351 citations
01 Jan 1983
TL;DR: The European Space Agency (ESA) as mentioned in this paper is the successor to the European Launcher Development Organization and the European Space Research Organization, which were created under separate conventions concluded in 1962 as European bases for the execution of space activities and programs.
Abstract: This chapter describes the establishment and role of European Space Agency (ESA). The ESA is the successor to the European Launcher Development Organization and the European Space Research Organization, which were created under separate conventions concluded in 1962 as European bases for the execution of space activities and programs. ESA was created by the Convention for the Establishment of a European Space Agency, which was opened for signature in Paris on May 30, 1975. The Director General, who is appointed by the council, acts as ESA's chief executive officer and legal representative. He reports annually to the council, attends its meetings, and may make proposals but has no vote. The administrative structure beneath the Director General consists of function oriented Directorates for Administration, Applications Programmes, Spacecraft Operations, Scientific Programmes, and Space Transportation Systems, as well as the Technical Directorate.
637 citations
Book•
03 Apr 2008
TL;DR: Filled with detailed illustrations and examples, this expert design tool takes you step-by-step through coordinate systems, deterministic and stochastic modeling, optimal estimation, and navigation system design.
Abstract: Design Cutting-Edge Aided Navigation Systems for Advanced Commercial & Military Applications
Aided Navigation is a design-oriented textbook and guide to building aided navigation systems for smart cars, precision farming vehicles, smart weapons, unmanned aircraft, mobile robots, and other advanced applications. The navigation guide contains two parts explaining the essential theory, concepts, and tools, as well as the methodology in aided navigation case studies with sufficient detail to serve as the basis for application-oriented analysis and design.
Filled with detailed illustrations and examples, this expert design tool takes you step-by-step through coordinate systems, deterministic and stochastic modeling, optimal estimation, and navigation system design. Authoritative and comprehensive, Aided Navigation features:
End-of-chapter exercises throughout Part I In-depth case studies of aided navigation systems Numerous Matlab-based examples Appendices define notation, review linear algebra, and discuss GPS receiver interfacing Source code and sensor data to support examples is available through the publisher-supported website
Inside this Complete Guide to Designing Aided Navigation Systems
• Aided Navigation Theory: Introduction to Aided Navigation • Coordinate Systems • Deterministic Modeling • Stochastic Modeling • Optimal Estimation • Navigation System Design • Navigation Case Studies: Global Positioning System (GPS) • GPS-Aided Encoder • Attitude and Heading Reference System • GPS-Aided Inertial Navigation System (INS) • Acoustic Ranging and Doppler-Aided INS
Table of contents
I. Theory
Part I: Overview
Chapter 1. Overview
Chapter 2. Reference Frames
Chapter 3. Deterministic Systems
Chapter 4. Stochastic Processes
Chapter 5. Optimal State Estimation
Chapter 6. Performance Analysis
Chapter 7. Navigation System Design
II. Application
Part II: Overview
Chapter 8. Global Positioning System
Chapter 9. GPS Aided Encoder-Based Dead-Reckoning
Chapter 10. AHRS
Chapter 11. Aided Inertial Navigation
Chapter 12. LBL and Doppler Aided INS
Appendix A: Notation
Appendix B: Linear Algebra Review
Appendix C: Calculation of GPS Satellite Position & Velocity
Appendix D: Quaternions
Bibliography
Index
603 citations
"Multi-Constellation GNSS Performanc..." refers methods in this paper
...There are a number of methods, including combining GNSS with other signals, sensors and data sources in an integrated navigation system (Groves, 2008; Farrell, 2008)....
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Book•
01 Apr 2013
TL;DR: The second edition of the Artech House book Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems as discussed by the authors offers a current and comprehensive understanding of satellite navigation, inertial navigation, terrestrial radio navigation, dead reckoning, and environmental feature matching.
Abstract: This newly revised and greatly expanded edition of the popular Artech House book Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems offers you a current and comprehensive understanding of satellite navigation, inertial navigation, terrestrial radio navigation, dead reckoning, and environmental feature matching . It provides both an introduction to navigation systems and an in-depth treatment of INS/GNSS and multisensor integration. The second edition offers a wealth of added and updated material, including a brand new chapter on the principles of radio positioning and a chapter devoted to important applications in the field. Other updates include expanded treatments of map matching, image-based navigation, attitude determination, acoustic positioning, pedestrian navigation, advanced GNSS techniques, and several terrestrial and short-range radio positioning technologies. The book shows you how satellite, inertial, and other navigation technologies work, and focuses on processing chains and error sources. In addition, you get a clear introduction to coordinate frames, multi-frame kinematics, Earth models, gravity, Kalman filtering, and nonlinear filtering. Providing solutions to common integration problems, the book describes and compares different integration architectures, and explains how to model different error sources. You get a broad and penetrating overview of current technology and are brought up to speed with the latest developments in the field, including context-dependent and cooperative positioning. DVD Included: Features eleven appendices, interactive worked examples, basic GNSS and INS MATLAB simulation software, and problems and exercises to help you master the material.
483 citations
"Multi-Constellation GNSS Performanc..." refers background or methods in this paper
...There are a number of methods, including combining GNSS with other signals, sensors and data sources in an integrated navigation system (Groves, 2008; Farrell, 2008)....
[...]
...DOP is calculated as described in (Misra and Enge, 2010, Groves, 2008)....
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...There are four important requirements of any navigation system: accuracy, availability, continuity and integrity (Misra and Enge, 2010; Groves, 2008)....
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Book•
30 Apr 2009
TL;DR: The reader discovers how A-GPS enables the computing of a position from navigation satellites in the absence of precise time, a topic that has not yet been covered in any other book.
Abstract: Assisted GPS (A-GPS) has been developed to provide greatly improved capabilities, helping GPS work better and faster in almost any location. Offering a detailed look at all the technical aspects and underpinnings of A-GPS, this unique book places emphasis on practical implementation. The book reviews standard GPS design, helping you understand why GPS requires assistance in the first place. You discover how A-GPS enables the computing of a position from navigation satellites in the absence of precise time - a topic not covered in any other book. Moreover, you learn how to design and analyze a high sensitivity GPS receiver and determine the achievable sensitivity. The book provides detailed worksheets that show how to compute, analyze, and improve the processing gain from the input signal at the antenna to the signal after the correlators. These worksheets are used in the book to generate families of curves that completely characterize receiver sensitivity, parameterized in terms of front end noise figure, coherent and noncoherent integration times. From this work a law of achievable sensitivity is derived and explained in the book. This cutting-edge volume discusses special forms of assistance data, industry standards for A-GPS, and government mandates for location of mobile phones. You also find coverage of future global navigation satellite systems and how they can be designed specifically for instant-fixes and high sensitivity. The book features numerous tables, worksheets, and graphs that illustrate key topics and provide the equivalent of a technical handbook for engineers who design or use A-GPS.
407 citations
"Multi-Constellation GNSS Performanc..." refers background in this paper
...The Compass orbits are generated from an unofficial description of the full global system (Van Diggelen, 2009)....
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