GPS Cross Correlation Mitigation Technique in Multipath Environment

2010 ◽  
Vol 439-440 ◽  
pp. 715-720
Author(s):  
Jun Yao Gao ◽  
Jing Shu Yang ◽  
Jia Zhao
Keyword(s):  
Interference Cancellation ◽  
Cross Correlation ◽  
Parallel Interference Cancellation ◽  
Multipath Environment ◽  
Simulation Results ◽  
The Cross ◽  
The Impact ◽  
Mitigation Technique

The paper investigates the cross correlation mitigation (CCM) technique in the multipath propagating environment. It analyses the impact of cross correlation firstly, then expounds the universal technique in CCM, at last presents an improved DPIC (Delayed Parallel Interference Cancellation) method based on MEDLL. The algorithm estimates the parameters of multipath by using MEDLL, reconstructs the strong signals IF utilizing these parameters, and mitigates the cross correlation with the aid of DPIC method. At last, simulation results prove the validity of this method.

DFCWs Design Based on Improved DPSO

2013 ◽  
Vol 333-335 ◽  
pp. 623-627
Author(s):  
Jing Jun Li ◽  
Yong Hua Jiang ◽  
Bo Dan ◽  
Wei Wei Gao
Keyword(s):  
Theoretical Analysis ◽  
Cross Correlation ◽  
Correlation Energy ◽  
Code Length ◽  
Discrete Particle ◽  
Frequency Coding ◽  
Simulation Results ◽  
The Cross ◽  
The Cost ◽  
Correlation Level

Orthogonal discrete frequency coding waveforms(DFCWs) is an ideal quasi-orthogonal waveform. This paper analyses the ambiguity function of DFCWs and the results indicate that the correlation characteristics of DFCWs have only relationship with the code length and coding order. Based on the theoretical analysis, we defined the cross-correlation energy as the cost function, and used the improved discrete particle swarmoptimization(DPSO) to optimize the order of DFCWs. The new signal can effectively restrain the cross-correlation level between the two DFCWs. Simulation results verify the effectiveness of the designed DFCWs.

Analyzing the Impact of COVID-19 on the Cross-Correlations between Financial Search Engine Data and Movie Box Office

2020 ◽  
pp. 2150021
Author(s):  
Renyu Wang ◽  
Yujie Xie ◽  
Hong Chen ◽  
Guozhu Jia
Keyword(s):  
Financial Market ◽  
Cross Correlation ◽  
Multifractal Spectrum ◽  
Movie Industry ◽  
Box Office ◽  
Cross Correlation Analysis ◽  
Cross Correlations ◽  
The Cross ◽  
Google Search ◽  
The Impact

This paper explores the COVID-19 influences on the cross-correlation between the movie market and the financial market. The nonlinear cross-correlations between movie box office data and Google search volumes of financial terms such as Dow Jones Industrial Average (DJIA), NASDAQ and PMI are investigated based on multifractal detrended cross-correlation analysis (MF-DCCA). The empirical results show there are nonlinear cross-correlations between movie market and financial market. Metrics such as Hurst exponents, singular exponents and multifractal spectrum demonstrate that the cross-correlation between movie market and financial market is persistent, and the cross-correlation in long term is more stable than that in short term. In the COVID-19 period, the multifractal features of cross-correlation become stronger implying that COVID-19 enhanced the complexity between the movie industry and the financial market. Furthermore, through the rolling window analysis, the Hurst exponent dynamic trends indicate that COVID-19 has a clear influence on the cross-correlation between movie market and financial market.

The Impact of Wavelength Step on Radial Velocity Error

2012 ◽  
Vol 239-240 ◽  
pp. 794-797
Author(s):  
Fang Zuo ◽  
A Li Luo
Keyword(s):  
Radial Velocity ◽  
Measurement Method ◽  
Cross Correlation ◽  
Stellar Spectra ◽  
Velocity Error ◽  
Target Spectrum ◽  
Different Types ◽  
The Cross ◽  
The Impact ◽  
Internal Error

Radial velocity (RV) of a star caused by Doppler shift could be easily measured by cross-correlated it’s spectrum with a serial template. Generally, the RV error of a spectrum always is given by the widths of the cross-correlation function of the target spectrum and related template spectrum. RV error comes from many factors, causing from instruments, observation weather, etc.. In this paper, simulation with different types of stellar spectra, which has different temperature, is implemented. The results show that there is an internal error which is not generated by the calculation steps for a given resolution step, for example, 5km/s error exists in the cross-correlation based RV measurement method for resolution about R~2000. The simulation also proves that this error could not be avoided for any type of stars.

scholarly journals Adaptive seismic noise reduction using Wiener filter

2019 ◽  
Vol 8 (1) ◽  
pp. 12-20
Author(s):  
Sesar Prabu Dwi Sriyanto
Keyword(s):  
Seismic Noise ◽  
Cross Correlation ◽  
Seismic Station ◽  
Wiener Filter ◽  
Dominant Frequency ◽  
Observation System ◽  
Before And After ◽  
Filter Process ◽  
The Cross ◽  
The Impact

Seismic noise disrupts the earthquake observation system due to the frequency and amplitude of seismic noise similar to the earthquake signal. The filter process is one of the methods that can be used to reduce seismic noise. In this study, the Wiener filter algorithm was designed with the Decision-Directed method for Apriori SNR estimation. This filter was chosen because it is adaptive, so it can adjust to environmental conditions without requiring manual parameter settings. The data used are earthquake signals that occur in the Palu area, Central Sulawesi, which are recorded on PKA29 temporary seismic station from February 3 to April 28, 2015. After each signal data has been filtered, then it is evaluated by calculating SNR differences before and after filtering, the signal's dominant frequency, and the cross-correlation of the signal before and after filtering. As a result, the Wiener filter is able to reduce the noise content in earthquake signals according to noisy frequencies before earthquake signals. The impact is that SNR has increased with an average of 8.056 dB. In addition, this filter is also able to maintain the shape of earthquake signals. This is indicated by the normalization value of the cross-correlation between signals before and after the filter which ranges from 0.703 to 1.00.

scholarly journals Synchronization in Monkey Motor Cortex During a Precision Grip Task. I. Task-Dependent Modulation in Single-Unit Synchrony

2001 ◽  
Vol 85 (2) ◽  
pp. 869-885 ◽  
Author(s):  
S. N. Baker ◽  
R. Spinks ◽  
A. Jackson ◽  
R. N. Lemon
Keyword(s):  
Motor Cortex ◽  
Firing Rate ◽  
Cross Correlation ◽  
Primary Motor Cortex ◽  
Precision Grip ◽  
Average Width ◽  
Population Synchrony ◽  
Hold Period ◽  
The Cross ◽  
The Impact

Neural synchronization in the cortex, and its potential role in information coding, has attracted much recent attention. In this study, we have recorded long spike trains (mean, 33,000 spikes) simultaneously from multiple single neurons in the primary motor cortex (M1) of two conscious macaque monkeys performing a precision grip task. The task required the monkey to use its index finger and thumb to move two spring-loaded levers into a target, hold them there for 1 s, and release for a food reward. Synchrony was analyzed using a time-resolved cross-correlation method, normalized using an estimate of the instantaneous firing rate of the cell. This was shown to be more reliable than methods using trial-averaged firing rate. A total of 375 neurons was recorded from the M1 hand area; 235 were identified as pyramidal tract neurons. Synchrony was weak [mean k′ = 1.05 ± 0.04 (SD)] but widespread among pairs of M1 neurons (218/1359 pairs with above-chance synchrony), including output neurons. Synchrony usually took the form of a broad central peak [average width, 18.7 ± 8.7 (SD) ms]. There were marked changes during different phases of the task. As a population, synchrony was greatest during the steady hold period in striking contrast to the averaged cell firing rate, which was maximal when the animal was moving the levers into target. However, the modulation of synchrony during task performance showed considerable variation across individual cell pairs. Two types of synchrony were identified: oscillatory (with periodic side lobes in the cross-correlation) and nonoscillatory. Their relative contributions were quantified by filtering the cross-correlations to exclude either frequencies from 18 to 37 Hz or all higher and lower frequencies. At the peak of population synchrony during the hold period, about half (51.7% in one monkey, 56.2% in the other) of the synchronization was within this oscillatory bandwidth. This study provides strong support for assemblies of neurons being synchronized during specific phases of a complex task with potentially important consequences for both information processing within M1 and for the impact of M1 commands on target motoneurons.

scholarly journals Improved hybrid inter and intra-cell interference cancellation mechanism for LTE-A HETNETS

2018 ◽  
Vol 7 (3) ◽  
pp. 1381 ◽  
Author(s):  
Shibu S ◽  
Saminadan V
Keyword(s):  
Spectral Efficiency ◽  
Interference Cancellation ◽  
Network Performance ◽  
Low Cost ◽  
Least Square ◽  
Energy Aware ◽  
Heavy Load ◽  
Light Load ◽  
Simulation Results ◽  
The Impact

In Heterogeneous networks (HetNets), operators need to ensure reliable service to their users in terms of network performance and low cost. The growing demand of user traffic necessitates the incorporation of femto cells and pico cells for facilitating seamless services. The network performance of Long Term Evolution (LTE) and LTE Advanced (LTE-A) HetNets is drastically influenced by the degree of interference that is realized in the inter-cell and intra-cell during communication. In this paper, an Improved Hybrid inter and intra-cell interference cancellation mechanism (CRS-IIC-LFLS) is propounded for handling interference at the inter and intra-cell level. Inter-cell interference cancellation is achieved through the use of an Improved CRS-IIC algorithm that uses the benefits of Linear Filtering Least Square (LFLS) method for channel estimation. CRS-IIC-LFLS is found to potent in rapid interference cancellation facilitation by suppressing the noise level, reducing the impact of fading channel and inherently eliminates small energy aware paths from large energy aware paths. The Simulation results confirm that the proposed scheme ensures better network throughput under light load, medium load and heavy load conditions of the network. The results prove that the performance of CRS-IIC-LFLS with CRS-IC-LFLS and CRS-IC-LLS based on spectral efficiency is improved at a mean rate of 21% and 26% respectively. The simulation results also portrays that the increase in the spectral efficiency of CRS-IIC-LFLS (64-QAM) is phenomenal to a maximum improvement of 12% over CRS-IIC-LFLS (16-QAM).  

A Simplified Cascaded Modular Structure for the Implementation of MVDR Detector

2011 ◽  
Vol 128-129 ◽  
pp. 491-494
Author(s):  
Zhong Jie Li ◽  
Cui Tao Zhu ◽  
Shao Ping Chen
Keyword(s):  
Computer Simulation ◽  
Interference Cancellation ◽  
Cross Correlation ◽  
Weight Vector ◽  
Modular Structure ◽  
Maximum Magnitude ◽  
Asymptotic Condition ◽  
Correlation Criterion ◽  
The Cross

A cascaded modular structure is proposed to implement the blind MVDR detector. In each module of the structure, a vector filter is introduced for adaptive interference cancellation. The weight vector is determined based on a maximum magnitude cross correlation criterion which maximizes the magnitude of the cross correlation between the output of the nonadaptive filter and that of the weight vector filter. The performance of the proposed receiver has been evaluated via computer simulation and shown to be comparable to that of the optimum method under asymptotic condition. When the number of received vectors is non-ideal, the proposed method outperform the optimum method.

The Effect of “Wuhan Closure” on the COVID-19 Pandemic in China

2021 ◽  
pp. 2150052
Author(s):  
Jian Wang ◽  
Wei Shao ◽  
Yan Yan ◽  
Junseok Kim
Keyword(s):  
Correlation Analysis ◽  
Cross Correlation ◽  
Newly Diagnosed ◽  
Daily Number ◽  
Number Of Patients ◽  
Cross Correlation Analysis ◽  
Cross Correlations ◽  
The Cross ◽  
The Impact

In this study, we analyzed daily records of newly diagnosed cases in Wuhan, Hubei excluding Wuhan (HEW), and China excluding Hubei (CEH) to investigate the impact of the new coronavirus outbreak in Wuhan on cities around it and throughout China. We used multifractal detrended cross-correlation analysis (MF-DXA) method to investigate the correlations between the daily number of patients in Wuhan and HEW as well as in Wuhan and CEH. We concluded that the cross-correlations between the daily number of patients in Wuhan and HEW were higher than those between the daily number of patients in Wuhan and CEH because the multifractal features of Wuhan and HEW are greater than those of Wuhan and CEH. We also found that the “Wuhan closure” conducted on January 23 resulted in a decrease in cross-correlations between Wuhan and CEH.

scholarly journals Consistent radial velocities of classical Cepheids from the cross-correlation technique

2019 ◽  
Vol 631 ◽  
pp. A37 ◽  
Author(s):  
S. Borgniet ◽  
P. Kervella ◽  
N. Nardetto ◽  
A. Gallenne ◽  
A. Mérand ◽  
...  
Keyword(s):  
Time Series ◽  
Line Profile ◽  
Cross Correlation ◽  
Radial Velocities ◽  
Spectral Lines ◽  
Computation Method ◽  
Custom Made ◽  
The Cross ◽  
The Impact ◽  
The Way

Context. Accurate radial velocities (vrad) of Cepheids are mandatory within the context of Cepheid distance measurements using the Baade-Wesselink technique. The most common vrad derivation method consists in cross-correlating the observed stellar spectra with a binary template and measuring a velocity on the resulting mean profile. Nevertheless, for Cepheids and other pulsating stars, the spectral lines selected within the template as well as the way of fitting the cross-correlation function (CCF) have a direct and significant impact on the measured vrad. Aims. Our first aim is to detail the steps to compute consistent CCFs and vrad of Cepheids. Next, this study aims at characterising the impact of Cepheid spectral properties and vrad computation methods on the resulting line profiles and vrad time series. Methods. We collected more than 3900 high-resolution spectra from seven different spectrographs of 64 Classical Milky Way (MW) Cepheids. These spectra were normalised and standardised using a single custom-made process on pre-defined wavelength ranges. We built six tailored correlation templates selecting unblended spectral lines of different depths based on a synthetic Cepheid spectrum, on three different wavelength ranges from 3900 to 8000 Å. Each observed spectrum was cross-correlated with these templates to build the corresponding CCFs, adopted as the proxy for the spectrum mean line profile. We derived a set of line profile observables as well as three different vrad measurements from each CCF and two custom proxies for the CCF quality and amount of signal. Results. This study presents a large catalogue of consistent Cepheid CCFs and vrad time series. It confirms that each step of the process has a significant impact on the deduced vrad: the wavelength, the template line depth and width, and the vrad computation method. The way towards more robust Cepheid vrad time series seems to go through steps that minimise the asymmetry of the line profile and its impact on the vrad. Centroid or first-moment vrad, that exhibit slightly smaller amplitudes but significantly smaller scatter than Gaussian or biGaussian vrad, should therefore be favoured. Stronger or deeper spectral lines also tend to be less asymmetric and lead to more robust vrad than weaker lines.

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