Multipath Effects In Gps Receivers
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Multipath Effects In Gps Receivers
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Author : Steven Miller
language : en
Publisher: Springer Nature
Release Date : 2022-05-31
Multipath Effects In Gps Receivers written by Steven Miller and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-05-31 with Technology & Engineering categories.
Autonomous vehicles use global navigation satellite systems (GNSS) to provide a position within a few centimeters of truth. Centimeter positioning requires accurate measurement of each satellite's direct path propagation time. Multipath corrupts the propagation time estimate by creating a time-varying bias. A GNSS receiver model is developed and the effects of multipath are investigated. MATLABtm code is provided to enable readers to run simple GNSS receiver simulations. More specifically, GNSS signal models are presented and multipath mitigation techniques are described for various multipath conditions. Appendices are included in the booklet to derive some of the basics on early minus late code synchronization methods. Details on the numerically controlled oscillator and its properties are also given in the appendix.
Multipath Effects In Gps Receivers
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Author : Steven Miller
language : en
Publisher: Morgan & Claypool Publishers
Release Date : 2015-12-01
Multipath Effects In Gps Receivers written by Steven Miller and has been published by Morgan & Claypool Publishers this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-12-01 with Technology & Engineering categories.
Autonomous vehicles use global navigation satellite systems (GNSS) to provide a position within a few centimeters of truth. Centimeter positioning requires accurate measurement of each satellite's direct path propagation time. Multipath corrupts the propagation time estimate by creating a time-varying bias. A GNSS receiver model is developed and the effects of multipath are investigated. MATLABtm code is provided to enable readers to run simple GNSS receiver simulations. More specifically, GNSS signal models are presented and multipath mitigation techniques are described for various multipath conditions. Appendices are included in the booklet to derive some of the basics on early minus late code synchronization methods. Details on the numerically controlled oscillator and its properties are also given in the appendix.
An Experimental Investigation Of The Effects Of Gps Satellite Multipath
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Author : Ruth Elizabeth Neilan
language : en
Publisher:
Release Date : 1986
An Experimental Investigation Of The Effects Of Gps Satellite Multipath written by Ruth Elizabeth Neilan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with categories.
Global Positioning System Gps Receiver Design For Multipaths Mitigation
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Author : El-Sayed Abdel-Salam Gadallah
language : en
Publisher:
Release Date : 1998-08-01
Global Positioning System Gps Receiver Design For Multipaths Mitigation written by El-Sayed Abdel-Salam Gadallah and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998-08-01 with Global Positioning System categories.
Multipath effects are a source of error degrading the accuracy of DGPS signal processing. The statistical models of multipath are determined by user location and, in addition are time varying. There is no unified statistical model for the multipath signal. Therefore the solution of the multipath problem using statistical models is difficult. This research introduces a new estimator that can detect the presence of multipath, can determine the unknown number of multipath components and can estimate multipath parameters in the GPS receiver (time delay and attenuation coefficients). Furthermore the multipath signal parameters are estimated at any instant of observation. The new estimator is based on maximum likelihood estimation applied to multiple observations of a linear model (regression form) of the received signal. In addition, the estimator is based on a recursive deployment of the multipath time delay. An improvement is achieved to the accuracy of multipath estimates at a low signal- to-noise level by applying Kalman filtering as a cascaded estimator. Kalman filtering application can be considered as an important tool for separating the direct path signal from multipath in noise. This dissertation also includes the design of new modified tracking loops endowed with the mentioned estimator: a modified Phase Lock Loop (PLL) for carrier tracking and a modified Delay Locked- Loop (DLL) in the code tracking. The modified loops can properly track the received direct signal in the presence of multipaths where the standard tracking loops are disabled. Simulations of the standard and the modified loops are presented. Tracking and performance in noise are investigated and a future work is suggested.
Cepstral Processing For Gps Multipath Detection And Mitigation
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Author : Charles D. Ormsby
language : en
Publisher:
Release Date : 1997-12-01
Cepstral Processing For Gps Multipath Detection And Mitigation written by Charles D. Ormsby and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997-12-01 with Global Positioning System categories.
This work presents a novel approach to code phase multipath mitigation for Global Positioning System (GPS) receivers. It uses the power and complex cepstra for multipath detection and mitigation prior to code phase tracking by a standard non-coherent delay lock loop. Cepstral theory is presented to demonstrate how multipath reflection delays can be detected through the use of the power cepstrum. Filtering can then be performed on the complex cepstrum to remove multipath effects in the cepstral domain. Finally, an inverse complex cepstrum is calculated yielding a theoretically multipath free direct path estimate in the time domain. Simulations are presented to verify the applicability of cepstral techniques to the problem of GPS multipath mitigation. Results show that, under noiseless conditions, cepstral processing prior to code tracking by a standard non-coherent delay lock loop leads to lower code tracking biases than direct tracking of the composite multipath signal by a narrow correlator receiver. Finally, this work shows that cepstral processing is highly sensitive to additive white Gaussian noise effects, leading to the conclusion that methods of limiting noise effects must be developed before this technique will be applicable in actual GPS receivers.
Analysis And Simulation Of A New Code Tracking Loop For Gps Multipath Mitigation
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Author : Mark C. Laxton
language : en
Publisher:
Release Date : 1996-12-01
Analysis And Simulation Of A New Code Tracking Loop For Gps Multipath Mitigation written by Mark C. Laxton and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996-12-01 with Global Positioning System categories.
This thesis proposes a new direct sequence spread spectrum (DS/SS) code phase tracking loop which mitigates the effects of multipath interference on code phase tracking error; such errors can translate to significant range measurement errors in DS/SS ranging systems such as Global Positioning System (GPS). The new code tracking loop, called the modified RAKE delay lock loop (MRDLL), uses maximum likelihood (ML) signal parameter estimation to determine the amplitude, carrier phase, and relative propagation delay of both a direct path and a reflected signal; a multiple correlator code phase tracking loop then exploits these ML signal estimates to remove the tracking error introduced by the reflection. A preliminary analysis showed that the MRDLL's linear tracking region varied with the reflected signal parameters; therefore, an adaptive loop controller (ALC) was introduced to allow the loop designer to fix dynamic specifications such as loop natural frequency. Analysis and computer simulations demonstrated that, when multipath was present, the MRDLL exhibited a significantly lower steady-state code phase tracking error than that of the standard noncoherent delay lock loop (NCDLL), which is typically used in GPS receivers. In an ideal multipath-free environment, the NCDLL is still the best choice for code phase tracking. This GPS receiver design technology will benefit the entire aviation community by eliminating or reducing the dominant source of error in differential GPS-based instrument landing systems, resulting in improved ILS safety, reliability, and integrity. In relative GPS applications, such as precision guided munitions, lethality is improved via elimination of multipath contribution to targeting error. In all GPS applications, the (no longer dominant) error contribution of multipath can be eliminated, yielding enhanced pog(,h-H1
A Gps Code Tracking Receiver Design For Multipath Mitigation Using Maximum Likelihood Estimation
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Author : Fred Baier
language : en
Publisher:
Release Date : 1997-12-01
A Gps Code Tracking Receiver Design For Multipath Mitigation Using Maximum Likelihood Estimation written by Fred Baier and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997-12-01 with categories.
The NAVSTAR Global Positioning System (GPS) is currently used in many applications requiring precise positioning data. Improving the precise positioning information requires the removal of errors that perturb the received signals. The errors introduced by multiple propagation channels, termed multipath, are not easily removed. These channels are caused by reflective surfaces near the receiver. As such, multipath is uncorrelated between receivers and, thus, cannot be removed through differencing techniques. This thesis investigates a GPS code tracking loop design which uses maximum likelihood (ML) estimation to determine amplitude and phase information of the multipath signal which are used to adjust code tracking to account for multipath effects. Analysis of the operations that govern this design for the case of a single reflection shows that it has no steady state tracking error. Results of simulations indicate that the code tracking loop, in conjunction with the MLE, mitigate the effects of multipath and improves code tracking performance over the narrow correlator NCDLL for most scenarios analyzed. Overall results of simulations indicate that the implementation of the maximum likelihood estimator (MLE) in conjunction with the code tracking loop has the potential to enhance code tracking performance over that offered by the narrow correlator NCDLL in a GPS environment.
A Software Defined Gps And Galileo Receiver
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Author : Kai Borre
language : en
Publisher: Springer Science & Business Media
Release Date : 2007-08-03
A Software Defined Gps And Galileo Receiver written by Kai Borre and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-08-03 with Technology & Engineering categories.
This book explore the use of new technologies in the area of satellite navigation receivers. In order to construct a reconfigurable receiver with a wide range of applications, the authors discuss receiver architecture based on software-defined radio techniques. The presentation unfolds in a user-friendly style and goes from the basics to cutting-edge research. The book is aimed at applied mathematicians, electrical engineers, geodesists, and graduate students. It may be used as a textbook in various GPS technology and signal processing courses, or as a self-study reference for anyone working with satellite navigation receivers.
Analysis Of Multipath Effects As A Repeatable Phenomenon Due To Satellite To Antenna Geometries
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Author : Maricela Estrada Rodríguez
language : en
Publisher:
Release Date : 1997
Analysis Of Multipath Effects As A Repeatable Phenomenon Due To Satellite To Antenna Geometries written by Maricela Estrada Rodríguez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with categories.
Global Positioning
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Author : Nel Samama
language : en
Publisher: John Wiley & Sons
Release Date : 2008-03-14
Global Positioning written by Nel Samama and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-03-14 with Technology & Engineering categories.
From stars to terrestrial networks and satellites From outdoors to indoors From ancient to future applications From techniques to technologies . . . The field of radionavigation signals and systems has seen significant growth in recent years. Satellite systems are very efficient, but owing to their limited exposure and/or availability in some environments, they do not cover the whole spectrum of applications. Thus, many other positioning techniques are being developed. Now, Global Positioning presents an overview of the strengths and weaknesses of various systems with a specific emphasis on those that are satellite-based. Beginning with a description of the evolution of positioning systems, the book provides detailed coverage of the three main Global Navigation Satellite System (GNSS) constellations, discusses how to cope with indoor positioning, defines development activities and commercial positioning, and proposes a vision for the future of the field. Special features of the book include: Exercises to test and challenge the reader's understanding Direct comparison between constellations and other positioning systems Mathematical content kept to a minimum in order to maximize accessibility and readability Descriptions of European and U.S. discussions for Galileo Historical aspects and links between the distant past and current systems Footnotes that provide hints and comments to the reader At a time when the positioning domain is experiencing such immense transformation, it is vital to have a solid understanding of the fundamental principles, current tech-nologies, and future improvements that will help estimate the performance and limita-tions of existing systems. Global Positioning fills an important need for professionals and students in a variety of fields who want a complete and authoritative overview of global positioning techniques.