Performance Benefit from Dual-Frequency GNSS-based Aviation Applications under Ionospheric Scintillation: A New Approach to Fading Process Modeling

2020 ◽  
Author(s):  
Kiyoung Sun ◽  
Hyeyeon Chang ◽  
Jiyun Lee ◽  
Jiwon Seo ◽  
Y. Jade Morton ◽  
...  
Keyword(s):  
Process Modeling ◽  
Ionospheric Scintillation ◽  
Dual Frequency ◽  
New Approach

scholarly journals Conductivity tomography at two frequencies

Geophysics ◽  
2003 ◽  
Vol 68 (2) ◽  
pp. 516-522 ◽  
Author(s):  
Junxing Cao ◽  
Zhenhua He ◽  
Jieshou Zhu ◽  
Peter K. Fullagar
Keyword(s):  
Single Frequency ◽  
Dual Frequency ◽  
Frequency Range ◽  
Frequency Method ◽  
New Approach ◽  
Electromagnetic Absorption ◽  
Universal Approach ◽  
Approximate Frequency ◽  
Transmitting Antenna

We present a new approach for crosshole radio tomography. Conductivity images of the investigated area are reconstructed from the ratio of the electric field intensities measured at two similar frequencies. The method largely avoids assumptions about the radiation pattern and in‐situ intensity of the transmitting antenna, which introduce errors in conventional single‐frequency crosshole electromagnetic‐absorption tomography. Application of the method to field data achieved an improvement in resolution of anomalies over traditional single‐frequency absorption tomography. The dual‐frequency method is not a universal approach; it is suitable for moderately conductive media (<0.01 S/m) over the approximate frequency range 1–100 MHz.

Modernizing Canadian Geodetic Survey’s precise GNSS orbit and clock system

2020 ◽  
Author(s):  
Mohammad Ali Goudarzi
Keyword(s):  
Geodetic Survey ◽  
Ionospheric Scintillation ◽  
Dual Frequency ◽  
Clock System ◽  
Combined Solution ◽  
Position Time Series ◽  
Wide Lane ◽  
Near Future ◽  
Processing Engine ◽  
New System

&lt;p&gt;In order to enable our new PPP processing engine and online service to work in full multi-GNSS mode, and provide high quality precise GNSS orbit and clock (POD) products to IGS and international geodetic community, Canadian Geodetic Survey (known as EMR) has started to modernize his POD system. The new system is based on GipsyX and in-house software development and will replace our current POD system in near future. When become operational, the new POD system will produce multi-GNSS precise orbit and clock corrections with ambiguity resolution along with wide-lane and phase biases using zero-differenced, dual-frequency, ionosphere-free phase and code observations in RINEX 2 and 3 formats estimated in combined solution. The new system also benefits from advanced features such as removing observations affected by ionospheric scintillation and ground stations affected by earthquake as well as real-time monitoring of estimated position time-series of ground stations, among others.&lt;/p&gt;

A business process modeling‐based approach to investigate complex processes

2012 ◽  
Vol 18 (1) ◽  
pp. 122-137 ◽  
Author(s):  
Faisal A. Abu Rub ◽  
Ayman A. Issa
Keyword(s):  
Business Process ◽  
Process Modeling ◽  
Business Processes ◽  
Business Process Modeling ◽  
New Techniques ◽  
New Approach ◽  
Content Type ◽  
Complex Processes ◽  
Model Complex

PurposeThe purpose of this paper is to develop a new approach to investigate complex processes, such as software development processes, using business process modeling.Design/methodology/approachThe paper presents an investigation into the use of role activity diagramming (RAD) to model complex processes in the software industry sector, with reference to the process of TestWarehouse as a case study.FindingsSystematic extension and quantitative analysis to RAD models led to the discovery of process bottlenecks, identification of cross functional boundary problems, and focused discussion about automation of processes.Research limitations/implicationsFurther work is required to validate and evaluate the proposed approach using several cases with different application domains and thus generalize the adopted approach.Practical implicationsA new approach has been used successfully to understand and analyze business processes. The tools and techniques that are used to perform the approach are not complicated and do not need much specialist expertise, so the approach is not only oriented toward specialists but also toward organizations' managers and staff.Originality/valueNew techniques have been developed by using process modelling to deepen the understanding and analyzing of complex organizational processes. This research implements a practical investigation which uses a case study to validate the new techniques.

New approach of the fouling process modeling in tangential filtration on cake

2017 ◽  
Vol 74 ◽  
pp. 71-86 ◽  
Author(s):  
Bassirou Mahamadou Harouna ◽  
Othmane Benkortbi ◽  
Mabrouk Hamadache ◽  
Salah Hanini ◽  
Abdeltif Amrane
Keyword(s):  
Process Modeling ◽  
New Approach ◽  
Tangential Filtration

Practical realizations in process modeling: Part I. A new approach to practical realization

AIChE Journal ◽  
1976 ◽  
Vol 22 (2) ◽  
pp. 298-309 ◽  
Author(s):  
Krishnamurthy Jayaraman ◽  
Leon Lapidus
Keyword(s):  
Process Modeling ◽  
Practical Realization ◽  
New Approach

A Study Of Ionospheric GPS Scintillation During Solar Maximum at UTeM Station

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Emad F. Aon ◽  
A. R. Othman ◽  
Y. H. Ho ◽  
R. Q. Shaddad
Keyword(s):  
Solar Maximum ◽  
Satellite System ◽  
Equatorial Region ◽  
Ionospheric Scintillation ◽  
Electron Content ◽  
Dual Frequency ◽  
Ionospheric Layer ◽  
Total Electron ◽  
Gps Satellites ◽  
Gps Scintillation

Wireless signals propagated along global positioning system (GPS) channel are affected by ionospheric electron density irregularities such that GPS signals may experience amplitude and phase fluctuations. The global navigation satellite system (GNSS), ionospheric scintillation, and total electron content (TEC) monitor (GISTM) receiver has been installed at UTeM, Malaysia (2.3139°N, 102.3183°E) for monitoring ionospheric scintillation at several frequencies. In this paper, the GPS ionospheric scintillations are concerned for the dual frequency L1 (fL1 = 1.57542 GHz) and L2C (fL2= 1.2276 GHz).  Ionospheric scintillation data has been collected during solar maximum cycle 2013-2014 for six months October 2013–March 2014. Solar activities significantly impact the ionospheric GPS scintillation, especially in the equatorial region where Malaysia is located. The GPS link is analyzed to investigate how the scintillation increases during the solar maximum cycle. When the sun flux is maximum, the total of electrons is increased in the ionospheric layer and the scintillation values gradually become high. The ionospheric amplitude/phase scintillation, carrier-to-noise (C/No) ratio, and availability of GPS satellites are reported in the proposed experimental GPS model. Consequently, for Malaysia, typical threshold received C/No ratio is 43 dB-Hz, implying that C/No ratio should be greater than 43 dB-Hz to receive good signals at the GPS receiver.

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