scholarly journals High-precision coseismic displacement estimation with a single-frequency GPS receiver

2015 ◽  
Vol 202 (1) ◽  
pp. 612-623 ◽  
Author(s):  
Bofeng Guo ◽  
Xiaohong Zhang ◽  
Xiaodong Ren ◽  
Xingxing Li
Keyword(s):  
High Precision ◽  
Single Frequency ◽  
Gps Receiver ◽  
Coseismic Displacement ◽  
Displacement Estimation

Detection of Spoofing Attack using Machine Learning based on Multi-Layer Neural Network in Single-Frequency GPS Receivers

2017 ◽  
Vol 71 (1) ◽  
pp. 169-188 ◽  
Author(s):  
E. Shafiee ◽  
M. R. Mosavi ◽  
M. Moazedi
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Late Phase ◽  
Machine Learning Algorithms ◽  
Computational Method ◽  
Single Frequency ◽  
Detection Accuracy ◽  
Gps Receiver ◽  
Navigation Data ◽  
Spoofing Detection

The importance of the Global Positioning System (GPS) and related electronic systems continues to increase in a range of environmental, engineering and navigation applications. However, civilian GPS signals are vulnerable to Radio Frequency (RF) interference. Spoofing is an intentional intervention that aims to force a GPS receiver to acquire and track invalid navigation data. Analysis of spoofing and authentic signal patterns represents the differences as phase, energy and imaginary components of the signal. In this paper, early-late phase, delta, and signal level as the three main features are extracted from the correlation output of the tracking loop. Using these features, spoofing detection can be performed by exploiting conventional machine learning algorithms such as K-Nearest Neighbourhood (KNN) and naive Bayesian classifier. A Neural Network (NN) as a learning machine is a modern computational method for collecting the required knowledge and predicting the output values in complicated systems. This paper presents a new approach for GPS spoofing detection based on multi-layer NN whose inputs are indices of features. Simulation results on a software GPS receiver showed adequate detection accuracy was obtained from NN with a short detection time.

scholarly journals Assessment of the position accuracy of a single-frequency GPS receiver designed for electromagnetic induction surveys

2018 ◽  
Vol 20 (1) ◽  
pp. 19-39 ◽  
Author(s):  
Sebastian Rudolph ◽  
Ben Paul Marchant ◽  
Lutz Weihermüller ◽  
Harry Vereecken
Keyword(s):  
Electromagnetic Induction ◽  
Single Frequency ◽  
Gps Receiver ◽  
Position Accuracy

Study on A High-Precision Digital Temperature-Control System for All-Solid-State Single-Frequency Green Laser

2015 ◽  
Vol 42 (9) ◽  
pp. 0902010
Author(s):  
靳晓丽 Jin Xiaoli ◽  
苏静 Su Jing ◽  
靳丕铦 Jin Pixian ◽  
王文哲 Wang Wenzhe ◽  
彭堃墀 Peng Kunchi
Keyword(s):  
Control System ◽  
Solid State ◽  
High Precision ◽  
Temperature Control ◽  
Green Laser ◽  
Single Frequency ◽  
Temperature Control System

The Analysis and Design of a Large Stroke with High-Precision Polarized Laser Interferometer System

2016 ◽  
Vol 679 ◽  
pp. 129-134
Author(s):  
Wan Duo Wu ◽  
Qiang Xian Huang ◽  
Chao Qun Wang ◽  
Ting Ting Wu ◽  
Hong Xie
Keyword(s):  
High Precision ◽  
Measurement Accuracy ◽  
Laser Interferometer ◽  
Laser Interferometry ◽  
Phase Shifting ◽  
Single Frequency ◽  
Rejection Method ◽  
The Common ◽  
Frequency Laser ◽  
Polarization Phase

The technique utilizing single-frequency laser interferometry has very high measurement accuracy, but it has rigorous requirements for optical design which is affected by many factors. In order to achieve single-frequency laser interferometry with large stroke and high precision, the integral layout, the polarization phase shifting technique and the common mode rejection method are adopted to design the length interferometry system. This paper analyzes factors and design requirements which affect measurement accuracy with large stroke. Based on polarization phase shifting technique, the system employs the four-beam-signal detection technique and the common mode rejection method, to make a differential processing of four mutually orthogonal signals. Thus, the influences of zero-drift of intensity and environmental change on system are reduced. Combined with a 200 phase subdivision, the system achieves the resolution with 0.8 nm. Under the VC++ environment, the displacement measurement results are compensated and corrected according to the environmental parameters. Compared with the Renishaw XL-80 laser interferometer, the system has better stability in short term. In the measuring range of 60 mm, the effectiveness of the system is verified.

scholarly journals Low-cost, high-precision, single-frequency GPS–BDS RTK positioning

GPS Solutions ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 1315-1330 ◽  
Author(s):  
Robert Odolinski ◽  
Peter J. G. Teunissen
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Single Frequency

AVALIAÇÃO DE ÁREA E DISTÂNCIAS EM PLANTA OBTIDA VIA GOOGLE EARTH

2017 ◽  
Vol 32 (2) ◽  
pp. 189
Author(s):  
Alexandre Luis Da Silva Felipe ◽  
Lincoln Gehring Cardoso
Keyword(s):  
Computer Program ◽  
High Precision ◽  
Reference Value ◽  
Google Earth ◽  
Gps Receiver ◽  
Total Station

O presente trabalho objetivou avaliar distâncias horizontais e área de um polígono obtido através de imagem do Google Earth tendo como referência levantamento topográfico realizado em campo utilizando-se Estação Total. O processamento dos dados do levantamento topográfico foi realizado através do programa computacional DataGeosis versão Office que acusou elevada precisão, garantindo sua condição de referência. As coordenadas obtidas pelo Google Earth foram submetidos ao software AutoCAD 13 para desenho. Com os dados assim obtidos foi possível a geração de plantas bem como cálculo de distâncias horizontais e áreas em ambos os casos. Foi possível se plotar ambas as plantas em único desenho por se considerar para o primeiro ponto da poligonal obtida por levantamento topográfico convencional, um par de coordenadas obtido por receptor GNSS no primeiro ponto da poligonal. Concluiu-se que valor de área obtida através do Google Earth ficando próximo do valor da referência, bem como seu entorno, não significa a precisão do polígono visto que comprometedoras diferenças em distâncias ora à maior ora à menor podem estar sendo compensadas, no entanto pode-se admitir esse procedimento comum para uso em planejamento rural.PALAVRAS-CHAVES: Levantamento topográfico; Imagem do Google EarthEVALUATION OF AREA AND DISTANCES IN A MAP OBTAINED BY GOOGLE EARTHABSTRACT: The purpose of this study was to compare horizontal distances and areas of a polygon obtained by Google Earth image based in a topographical survey as reference using  total station. The processing of the survey was made by computer program Datageosis Office version accused high precision and so used as reference. The coordinates obtained on Google Earth was submitted to the AutoCAD 13 software for drawing. The data obtained enabled the maps generation and also to calculate horizontal distances and areas in both cases. It was possible to plot the two maps in a single drawing by considering for the first point of the polygon obtained by conventional surveying, a pair of coordinates obtained by a GPS receiver. It was concluded that the area value obtained through Google Earth being next to the reference value, does not means the polygon precision due to the fact of differences in distances sometimes the largest and sometimes the smallest being compensated, however it is possible to admit this procedure for use in general rural planning.KEYWORDS: Topographical survey ;Google Earth Image.   

Extracting Ionosphere Scintillations Index Based on Single Frequency GPS Software Receiver

2012 ◽  
Vol 190-191 ◽  
pp. 1136-1143
Author(s):  
Zhi Huang ◽  
Hong Yuan ◽  
Qi Yao Zuo
Keyword(s):  
High Speed ◽  
Single Frequency ◽  
Scintillation Index ◽  
Ionospheric Scintillation ◽  
Signal Acquisition ◽  
Gps Receiver ◽  
Signal Loss ◽  
Software Receiver ◽  
Ionospheric Plasma Density ◽  
Gps Signal Acquisition

Scintillations are caused by ionospheric plasma-density irregularities and can lead to signal power fading, loss of lock of the carrier tracking loop in the GPS receiver. The traditional method of monitoring and mitigating scintillation is to transform commercial GPS receiver with modified hardware and embedded software. To better facilitate advance development GPS receiver under different condition, GPS software scintillation receiver is designed in this paper. The hardware scheme of high-speed GPS signal acquisition system is first discussed and implemented with FPGA and DSP architecture. Then, we describe receiver software processing algorithm, particularly the portion involving the scintillation signal acquisition and tracking, ionospheric scintillation index extracting and scintillation monitoring. The performance of software receiver is demonstrated under scintillation conditions. Relevant results show that software-receiver based approach can avoid weak signal loss and extract effectively ionospheric scintillation parameter compared with the traditional extracting method. Software receiver is suitable and reliable for the ionospheric scintillations monitoring, and can provide theoretical foundations and experimental preparations for future scintillation studies implemented with Chinese indigenous BeiDou-Ⅱ navigation and poisoning system.

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