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 Design and Performance Analysis of BDS-3 Integrity Concept

2021 ◽  
Vol 13 (15) ◽  
pp. 2860
Author(s):  
Cheng Liu ◽  
Yueling Cao ◽  
Gong Zhang ◽  
Weiguang Gao ◽  
Ying Chen ◽  
...  
Keyword(s):  
Satellite System ◽  
Navigation Satellite ◽  
Concept Design ◽  
Tree Model ◽  
System A ◽  
Design Values ◽  
Actual Operation ◽  
Integrity Risk ◽  
And Performance ◽  
Global Navigation Satellite

Compared to the BeiDou regional navigation satellite system (BDS-2), the BeiDou global navigation satellite system (BDS-3) carried out a brand new integrity concept design and construction work, which defines and achieves the integrity functions for major civil open services (OS) signals such as B1C, B2a, and B1I. The integrity definition and calculation method of BDS-3 are introduced. The fault tree model for satellite signal-in-space (SIS) is used, to decompose and obtain the integrity risk bottom events. In response to the weakness in the space and ground segments of the system, a variety of integrity monitoring measures have been taken. On this basis, the design values for the new B1C/B2a signal and the original B1I signal are proposed, which are 0.9 × 10−5 and 0.8 × 10−5, respectively. The hybrid alarming mechanism of BDS-3, which has both the ground alarming approach and the satellite alarming approach, is explained. At last, an integrity risk analysis and verification work were carried out using the operating data of the system in 2019. The results show that the actual operation of the system is consistent with the conceptual design, which satisfies the integrity performance promised by BDS-3 in the ICAO SAPRs.

A cost-effective beam forming structure for global navigation satellite system multipath mitigation and its assessment

2020 ◽  
pp. 1-21
Author(s):  
Qiongqiong Jia ◽  
Li-Ta Hsu ◽  
Bing Xu ◽  
Renbiao Wu
Keyword(s):  
Global Navigation Satellite System ◽  
Urban Areas ◽  
Cost Effective ◽  
Satellite System ◽  
Beam Forming ◽  
Navigation Satellite ◽  
Multipath Mitigation ◽  
Widespread Application ◽  
Global Navigation ◽  
Global Navigation Satellite

Abstract Array antenna beam forming has high potential to improve the performance of the global navigation satellite system (GNSS) in urban areas. However, the widespread application of array antennas for GNSS multipath mitigation is restricted by many factors, such as the complexity of the system, the computation load and conflicts between required performance, cost budget and limited room for the antenna placement. The scope of this work is triplicate. (1) The pre-correlation beam forming structure is first suggested for multipath mitigation to decrease the system complexity. (2) With the pre-correlation structure, the equivalence of adaptive beam forming to quiescent beam forming is revealed. Therefore, the computational load for beam forming is greatly decreased. (3) A theoretical model is established to link the benefits of beam forming with GNSS performance improvement in terms of pseudorange quality. The model can be used by industry to balance the aforementioned restrictions. Numerical results with different array settings are given, and a 2 × 2 rectangle array with $0.4\lambda $ element spacing is suggested as a cost-effective choice in GNSS positioning applications in urban canyon areas.

scholarly journals The Galileo Ground Segment Integrity Algorithms: Design and Performance

2008 ◽  
Vol 2008 ◽  
pp. 1-16 ◽  
Author(s):  
Carlos Hernández Medel ◽  
Carlos Catalán Catalán ◽  
Miguel Angel Fernández Vidou ◽  
Esther Sardón Pérez
Keyword(s):  
Algorithm Design ◽  
Satellite System ◽  
Navigation Satellite ◽  
Safety Requirements ◽  
Ground Segment ◽  
Global Positioning ◽  
Processing Facility ◽  
And Performance ◽  
Global Navigation Satellite ◽  
Software Prototype

Galileo, the European Global Navigation Satellite System, will provide to its users highly accurate global positioning services and their associated integrity information. The element in charge of the computation of integrity messages within the Galileo Ground Mission Segment is the integrity processing facility (IPF), which is developed by GMV Aerospace and Defence. The main objective of this paper is twofold: to present the integrity algorithms implemented in the IPF and to show the achieved performance with the IPF software prototype, including aspects such as: implementation of the Galileo overbounding concept, impact of safety requirements on the algorithm design including the threat models for the so-called feared events, and finally the achieved performance with real GPS and simulated Galileo scenarios.

scholarly journals A New Method for GNSS Multipath Mitigation with an Adaptive Frequency Domain Filter

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2514 ◽  
Author(s):  
Siqi Yu ◽  
Fei Guo ◽  
Xiaohong Zhang ◽  
Wanke Liu ◽  
Xin Li ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Frequency Spectrum ◽  
Fourier Transformation ◽  
Satellite System ◽  
Navigation Satellite ◽  
Multipath Mitigation ◽  
Multipath Effect ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
The Impact

Multipath is the dominant error source for most fixed Global Navigation Satellite Systems (GNSS) sites and stations. The presence of multipath, particularly the multipath effect on pseudorange measurement, seriously affects positioning accuracy. Unfortunately, multipath effect reduction is still a challenging issue in high-accuracy GNSS positioning applications due to its special properties. To minimize the impact of the multipath effect, this paper focused on pseudorange multipath mitigation. First, the frequency spectrum of the code-minus-carrier divergence (CMCD) for Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and BeiDou Navigation Satellite System (BDS) satellites observed in different environments were analyzed, where we found that periodic fluctuations appeared in GPS and GLONASS as well as medium earth orbit (MEO) and inclined geosynchronous satellite orbit (IGSO) of BDS satellites in some situations, which manifested as peaks in the frequency domain. The results showed that the location of the frequency peaks in the frequency domain, width, and basic frequency spectrum intensity were different between different satellites and environments, causing difficulty in reducing the error impact. To eliminate such period fluctuations mainly caused by the multipath effect, a novel method based on a frequency domain filter was proposed in this paper. One of the keys of the proposed method was the use of short-time Fourier transformation (STFT) in the GNSS signal data processing to calculate the accurate local frequency spectrum when code-minus-carrier divergence (CMCD) was assumed to be time varying. Once the frequency spectrum was obtained, a new spectrum peak extraction method was used to locate the peak frequency position. By interpolation and inverse Fourier transformation, the influence of the spectrum peaks could be effectively eliminated, thus improving pseudorange precision. The experimental results showed that the periodic multipath effect could be greatly reduced by the proposed method.

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