GNSS augmentation

About: GNSS augmentation is a research topic. Over the lifetime, 2478 publications have been published within this topic receiving 28513 citations. The topic is also known as: SBAS & Satellite Based Augmentation System.

Digital Satellite Navigation and Geophysics: A Practical Guide with GNSS Signal Simulator and Receiver Laboratory

Abstract: Bridge the gap between theoretical education and practical work experience with this hands-on guide to GNSS, which features:A clear, practical presentation of GNSS theory, with emphasis on GPS and GLONASSAll the essential theory behind software receivers and signal simulators Key applications in navigation and geophysics, including INS aiding, scintillation monitoring, earthquake studies and morePhysical explanations of various important phenomena, including the similarity of code delay and phase advance of GNSS signals, and negative cross-correlation between scintillation intensity and phase variations.Whether you are a practising engineer, a researcher or a student, you will gain a wealth of insights from the authors' twenty-five years of experience. You can explore numerous practical examples and case studies and get hands-on user experience with a bundled real-time software receiver, signal simulator and a set of signal data, enabling you to create your own GNSS lab for research or study.

Autonomous Vehicle Dynamic Model‐Based Navigation for Small UAVs

Abstract: This paper presents a novel approach to autonomous navigation for small UAVs, with no extra sensor added to the conventional INS/GNSS setup. The proposed method significantly increases the accuracy and reliability of autonomous navigation, especially for small UAVs with low-cost IMUs. This improvement is of special interest in the case of GNSS outages, where inertial coasting drifts very quickly. In the proposed architecture, the VDM provides the estimate of position, velocity, and attitude, which is updated within a filter based on available observations, such as IMU data or when available, GNSS measurements. The filter is capable of estimating wind velocity and dynamic model parameters, in addition to navigation states and IMU sensor errors. Monte Carlo simulations reveal major improvements in navigation accuracy compared to conventional INS/GNSS systems during GNSS outages of 5 min. A discussion on the observability is also presented at the end. Copyright (C) 2016 Institute of Navigation.

GNSS Signal Reliability Testing in Urban and Indoor Environments

Abstract: The availability of two GNSS (Global Navigation Satellite System), GPS and Galileo, will offer in future new possibilities to provide integrity and reliability information to the user both at signal and user levels due to increased redundancy. User-level reliability monitoring schemes, namely Receiver Autonomous Integrity Monitoring (RAIM), consist of statistically testing least- squares residuals of the observations on an epoch-by- epoch basis aiming towards reliable navigation fault detection and exclusion (FDE). Classic RAIM and FDE techniques are based on only GPS characteristics, so in this paper, methods will be discussed also suitable for a combined GPS/Galileo system with the focus on personal location in degraded signal environments. This paper concentrates on analyzing different navigation quality and reliability assessment procedures based on testing the GNSS least-squares residuals on an epoch-by- epoch basis. The focus will be on reliability testing schemes for degraded GNSS signals in urban conditions in order to obtain an acceptable position estimate, and analyzing the urban GNSS navigation accuracy conditions. The reliability testing schemes for integrated GPS/Galileo to be discussed include applying a global test for detecting an inconsistent location situation, a local test for localizing and eliminating measurement errors recursively and, in addition, certain measurement subset testing. The proposed FDE schemes are examined with simulated GPS/Galileo data and real-life urban GPS tests. Furthermore, some external reliability measures, Mean Radial Spherical Error and Distance Root Mean Squared estimates approximating the effect measurement errors have on the accuracy will be analyzed. This paper will provide an insight into user-level integrity and reliability monitoring and FDE schemes eligible for a future GNSS system particularly for degraded signal environments, where the conventional assumption of normally distributed errors does not necessarily hold. The aim is to improve solution reliability and provide additional accuracy information to the user in terms of approximated position error estimates.

Assessment of NeQuick ionospheric model for Galileo single-frequency users

Abstract: The ionosphere is the main error source in GNSS measurements and in extreme cases can degrade the positioning significantly, with errors exceeding 100 m; therefore, modelling and predicting of this type of error is crucial and critical. The ionospheric effect can be reduced using different techniques, such as dual-frequency receiver or suitable augmentation system (DGPS, SBAS); the aforesaid approaches involve the use of expensive devices and/or complex architectures. Single frequency stand-alone receivers are the cheapest and most widespread GNSS devices; they can estimate and partially correct the error due to the ionosphere, through adequate algorithms, which use parameters broadcasted by the navigation message. The aim of this paper is performance assessment of the ionospheric model NeQuick, adopted by the European GNSS Galileo for single frequency receivers. The analysis is performed in measurements domain and the data are collected in different geographical locations and in various geomagnetic conditions.

Jamming and Spoofing of GNSS Signals - An Underestimated Risk?!

Abstract: SUMMARY GNSS technology is used for many applications: The surveying industry uses GNSS for monitoring the continental drift, stakeout fixed-points, measuring maps of areas and many other location based services. The construction industry uses GNSS for machine control and logistics, agriculture for precise farming, power steering assists and other tasks like bringing out manure, harvesting and plowing. Over the last 10 years GNSS has also entered many daily life applications like car navigation and location based services (Google Maps, Facebook). But GNSS is also used as a sensor for many safety-critical applications: the example of guided lading approach of airplanes is well known, but it is less known that GNSS – and here specifically the Open Service of the US NAVSTAR GPS – is used as a crucial sensor for timing and synchronization of reference stations for telecommunication, electrical power supplies, exchange markets and banks. For many years, the availability and faultless function of GNSS has been taken for granted. Jamming (intentional interference targeting the unavailability of the system) as well as spoofing (faking of a false position/time towards a target GNSS receiver) was no concern for nearly all users except the military.