scholarly journals Performance Limits of GNSS Code-Based Precise Positioning: GPS, Galileo & Meta-Signals

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2196 ◽  
Author(s):  
Priyanka Das ◽  
Lorenzo Ortega ◽  
Jordi Vilà-Valls ◽  
François Vincent ◽  
Eric Chaumette ◽  
...  
Keyword(s):  
Time Delay ◽  
Sampling Rate ◽  
Satellite System ◽  
Time Delay Estimation ◽  
Performance Limits ◽  
Precise Positioning ◽  
Positioning Systems ◽  
Galileo E5 ◽  
Global Navigation Satellite ◽  
Cramer Rao Bound

This contribution analyzes the fundamental performance limits of traditional two-step Global Navigation Satellite System (GNSS) receiver architectures, which are directly linked to the achievable time-delay estimation performance. In turn, this is related to the GNSS baseband signal resolution, i.e., bandwidth, modulation, autocorrelation function, and the receiver sampling rate. To provide a comprehensive analysis of standard point positioning techniques, we consider the different GPS and Galileo signals available, as well as the signal combinations arising in the so-called GNSS meta-signal paradigm. The goal is to determine: (i) the ultimate achievable performance of GNSS code-based positioning systems; and (ii) whether we can obtain a GNSS code-only precise positioning solution and under which conditions. In this article, we provide clear answers to such fundamental questions, leveraging on the analysis of the Cramér–Rao bound (CRB) and the corresponding Maximum Likelihood Estimator (MLE). To determine such performance limits, we assume no external ionospheric, tropospheric, orbital, clock, or multipath-induced errors. The time-delay CRB and the corresponding MLE are obtained for the GPS L1 C/A, L1C, and L5 signals; the Galileo E1 OS, E6B, E5b-I, and E5 signals; and the Galileo E5b-E6 and E5a-E6 meta-signals. The results show that AltBOC-type signals (Galileo E5 and meta-signals) can be used for code-based precise positioning, being a promising real-time alternative to carrier phase-based techniques.

Urban Fleet Monitoring with GPS and GLONASS

1998 ◽  
Vol 51 (3) ◽  
pp. 382-393 ◽  
Author(s):  
M. Tsakiri ◽  
M. Stewart ◽  
T. Forward ◽  
D. Sandison ◽  
J. Walker
Keyword(s):  
Global Positioning System ◽  
Public Transport ◽  
Urban Areas ◽  
Dead Reckoning ◽  
Satellite System ◽  
Basic Function ◽  
Positioning System ◽  
Positioning Systems ◽  
Global Positioning ◽  
Global Navigation Satellite

The increasing volume of traffic in urban areas has resulted in steady growth of the mean driving time on fixed routes. Longer driving times lead to significantly higher transportation costs, particularly for vehicle fleets, where efficiency in the distribution of their transport tasks is important in staying competitive in the market. For bus fleets, the optimal control and command of the vehicles is, as well as the economic requirements, a basic function of their general mission. The Global Positioning System (GPS) allows reliable and accurate positioning of public transport vehicles except within the physical limitations imposed by built-up city ‘urban canyons’. With a view to the next generation of satellite positioning systems for public transport fleet management, this paper highlights the limitations imposed on current GPS systems operating in the urban canyon. The capabilities of a future positioning system operating in this type of environment are discussed. It is suggested that such a system could comprise receivers capable of integrating the Global Positioning System (GPS) and the Russian equivalent, the Global Navigation Satellite System (GLONASS), and relatively cheap dead-reckoning sensors.

scholarly journals Blind Spoofing GNSS Constellation Detection Using a Multi-Antenna Snapshot Receiver

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5439
Author(s):  
Johannes Rossouw van der Merwe ◽  
Alexander Rügamer ◽  
Wolfgang Felber
Keyword(s):  
Clustering Algorithms ◽  
Satellite System ◽  
System Level ◽  
Navigation Satellite ◽  
Positioning Systems ◽  
Test Setup ◽  
Counter Method ◽  
Eigen Decomposition ◽  
Global Navigation Satellite ◽  
Gnss Constellation

Spoofing of global navigation satellite system (GNSS) signals threatens positioning systems. A counter-method is to detect the presence of spoofed signals, followed by a warning to the user. In this paper, a multi-antenna snapshot receiver is presented to detect the presence of a spoofing attack. The spatial similarities of the array steering vectors are analyzed, and different metrics are used to establish possible detector functions. These include subset methods, Eigen-decomposition, and clustering algorithms. The results generated within controlled spoofing conditions show that a spoofed constellation of GNSS satellites can be successfully detected. The derived system-level detectors increase performance in comparison to pair-wise methods. A controlled test setup achieved perfect detection; however, in real-world cases, the performance would not be as ideal. Some detection metrics and features for blind spoofing detecting, with an array of antennas, are identified, which opens the field for future advanced multi-detector developments.

scholarly journals A New Multipath Mitigation Method for GNSS Receivers Based on an Antenna Array

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Sébastien Rougerie ◽  
Guillaume Carrié ◽  
François Vincent ◽  
Lionel Ries ◽  
Michel Monnerat
Keyword(s):  
Satellite System ◽  
Navigation Satellite ◽  
Tracking Loop ◽  
Multipath Mitigation ◽  
Expectation Maximisation ◽  
Gnss Receivers ◽  
Reduced Complexity ◽  
And Performance ◽  
Global Navigation Satellite ◽  
Cramer Rao Bound

The well-known Space-Alternating Generalized Expectation Maximisation (SAGE) algorithm has been recently considered for multipath mitigation in Global Navigation Satellite System (GNSS) receivers. However, the implementation of SAGE in a GNSS receiver is a challenging issue due to the numerous number or parameters to be estimated and the important size of the data to be processed. A new implementation of the SAGE algorithm is proposed in this paper in order to reach the same efficiency with a reduced complexity. This paper focuses on the trade-off between complexity and performance thanks to the Cramer Rao bound derivation. Moreover, this paper shows how the proposed algorithm can be integrated with a classical GNSS tracking loop. This solution is thus a very promising approach for multipath mitigation.

scholarly journals Analysis of the Impact of Multipath on Galileo System Measurements

2021 ◽  
Vol 13 (12) ◽  
pp. 2295
Author(s):  
Dominik Prochniewicz ◽  
Maciej Grzymala
Keyword(s):  
Satellite System ◽  
Navigation Systems ◽  
Short Baseline ◽  
Phase Measurements ◽  
Galileo E5 ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Space Segment ◽  
Gps Observations

Multipath is one of the major source of errors in precise Global Navigation Satellite System positioning. With the emergence of new navigation systems, such as Galileo, upgraded signals are progressively being used and are expected to provide greater resistance to the effects of multipath compared to legacy Global Positioning System (GPS) signals. The high quality of Galileo observations along with recent development of the Galileo space segment can therefore offer significant advantages to Galileo users in terms of the accuracy and reliability of positioning. The aim of this paper is to verify this hypothesis. The multipath impact was determined both for code and phase measurements as well as for positioning results. The code multipath error was determined using the Code-Minus-Carrier combination. The influence of multipath on phase observations and positioning error was determined using measurements on a very short baseline. In addition, the multipath was classified into two different types: specular and diffuse, using wavelet transform. The results confirm that the Galileo code observations are more resistant to the multipath effect than GPS observations. Among all of the observations examined, the lowest values of code multipath errors were recorded for the Galileo E5 signal. However, no advantage of Galileo over GPS was observed for phase observations and for the analysis of positioning results.

scholarly journals Combined Methodologies for the Survey and Documentation of Historical Buildings: The Castle of Scalea (CS, Italy)

Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2384-2397
Author(s):  
Eugenio Donato ◽  
Dario Giuffrida
Keyword(s):  
Building Materials ◽  
New Technologies ◽  
Satellite System ◽  
Great Effort ◽  
Architectural Drawing ◽  
Positioning Systems ◽  
Close Range ◽  
Global Navigation Satellite ◽  
High Level ◽  
Survey Methodologies

In the last few years, new technologies have become indispensable tools for specialists in the field of cultural heritage for the analysis, reconstruction and interpretation of data but also for promotion of artefacts or buildings sometimes inaccessible or in a bad state of conservation. The discipline of geomatics offer many opportunities and solutions for integrated digital surveys and the documentation of heritage (point-based methods, image-based photogrammetry and their combination): These data can be processed in order to derive metric information and share them using databases or GIS (geographic information system) tools. This paper is focused on the description of combined survey methodologies adopted for the geometric and architectural documentation of the site and surviving structures of the Castel of Scalea (Cosenza, Italy). It is a typical context where traditional survey procedures do not fully succeed or require a longer amount of time and great effort if a high level of accuracy is requested: For this reason, aerial close-range digital photogrammetry enhanced by the GNSS (global navigation satellite system), and total station positioning systems have been used at various levels of detail for the production of a detailed 3D model and 2D thematic maps with an excellent level of in the positioning of the structures and in the architectural drawing. Thanks to the collected dataset, it was possible to better identify the building units (CF), to digitize the limits of the masonry stratigraphic units (USM), and to draw up a first constructive diachronic sequence hypothesis on which to base chronology. Moreover, some particular masonry techniques have been sampled and compared at the regional level with the aim to better dating of constructive expedients. It was finally demonstrated how the use of integrated methodologies allows us to obtain a complete and detailed documentation including information regarding not only architectural and geometrical features but also archaeological and historical elements, building materials and decay evidences—all useful as support of the interpretation of data.

scholarly journals PAU/GNSS-R: Implementation, Performance and First Results of a Real-Time Delay-Doppler Map Reflectometer Using Global Navigation Satellite System Signals

Sensors ◽  
2008 ◽  
Vol 8 (5) ◽  
pp. 3005-3019 ◽  
Author(s):  
Juan Marchan-Hernandez ◽  
Adriano Camps ◽  
Nereida Rodriguez-Alvarez ◽  
Xavier Bosch-Lluis ◽  
Isaac Ramos-Perez ◽  
...  
Keyword(s):  
Time Delay ◽  
Real Time ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
First Results ◽  
Global Navigation ◽  
Global Navigation Satellite

scholarly journals Envelope and Wavelet Transform for Sound Localisation at Low Sampling Rates in Wireless Sensor Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
O. M. Bouzid ◽  
G. Y. Tian ◽  
J. Neasham ◽  
B. Sharif
Keyword(s):  
Wavelet Transform ◽  
Time Delay ◽  
Sampling Rate ◽  
Time Delay Estimation ◽  
Wireless Sensor ◽  
Estimation Accuracy ◽  
Memory Space ◽  
Time Frequency ◽  
Sound Localisation ◽  
Huge Data

High sampling frequencies in acoustic wireless sensor network (AWSN) are required to achieve precise sound localisation. But they are also mean analysis time and memory intensive (i.e., huge data to be processed and more memory space to be occupied which form a burden on the nodes limited resources). Decreasing sampling rates below Nyquist criterion in acoustic source localisation (ASL) applications requires development of the existing time delay estimation techniques in order to overcome the challenge of low time resolution. This work proposes using envelope and wavelet transform to enhance the resolution of the received signals through the combination of different time-frequency contents. Enhanced signals are processed using cross-correlation in conjunction with a parabolic fit interpolation to calculate the time delay accurately. Experimental results show that using this technique, estimation accuracy was improved by almost a factor of 5 in the case of using 4.8 kHz sampling rate. Such a conclusion is useful for developing precise ASL without the need of any excessive sensor resources, particularly for structural health monitoring applications.

AltBOC Receiver Design and Tracking Performance Analyze

2012 ◽  
Vol 529 ◽  
pp. 9-13
Author(s):  
Wei Dong He ◽  
Xiao Chun Lu ◽  
Xiao Feng Chang ◽  
Cheng Yan He ◽  
Yong Nan Rao ◽  
...  
Keyword(s):  
Satellite System ◽  
Receiver Design ◽  
Code Tracking ◽  
Large Bandwidth ◽  
Altboc Signal ◽  
Galileo E5 ◽  
Global Navigation Satellite ◽  
Performance Analyze ◽  
Processing Techniques ◽  
Signal Processing Techniques

The Galileo E5 signal is by far the most sophisticated signal among all the signals used for Global Navigation satellite system. Galileo receivers capable of tracking E5 will benefit from much better performance in terms of measurement accuracy and multipath suppression. Compared with traditional receivers for BPSK or even BOC signals, E5(AltBOC) signal processing techniques requires much more challenging due to the stems of the extremely large bandwidth and inherently complex correlations. This paper aims to present the receiving methodology and the architecture of tracking. The architecture of the tracking channel is discussed alongside with related algorithms and impact of code tracking jitter is evaluated finally.

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