The African VLBI Network (AVN) is an initiative by SKA-SA to establish VLBI stations on the African Continent through conversion of existing telecommunications facilities or building new facilities. The immediate focus is on converting an existing 32m satellite communication antenna at Nkutunse, Ghana as a joint venture between SKA-SA and Ghana Atomic Energy Commission (GAEC). Phase one of these conversions would include the application of pointing direction of these antennas. OSKAR simulator is therefore used to simulate Ghana’s antenna to determine the beam patterns at different intensities of Stokes I, Q, U and V. This would help research scientists and engineers to know the amount of field strength being received by these antennas. OSKAR presented the beam pattern in a form of geometric dipole showing clearly the field strength at different intensities.

 

Published In : IJCSN Journal Volume 3, Issue 4

Date of Publication : August 2014

Pages : 225 - 228

Figures : 04

Tables : --

Publication Link : Beam Pattern Simulation of Nkutunse Antenna

 

 

 

Alexander Akoto-Danso : works as an Assistant Research Scientist at the Ghana Space and Technology Institute. He holds a Master's in Computational Nuclear Science and Engineering (2011) and holds a Bsc. Mathematics. (2006) His interest is in High-performance Computing, Parallel computing, Computational Engineering, Digital Signal Processing, Climate modelling, Industrial and Systems engineering. He is a member of the Ghana Nuclear Society.

Severin Azankpo : works at GAEC as the head of Mechanical Department. He has BSc. Mechanical Engineering at Kwame Nkrumah University of Science and Technology. He has worked in different companies as a role of project engineer with rich experience in design, fabrication and installatiojn of steel structures. His main research interest is in Mechanical and Structural engineering of antenna. He is currently working on how to quantify the pointing accuracy and tracking performance of radio telescope structures.

Emmanuel Proven- Adzri : is working as an Assistant Research Scientist at Ghana Space Science and Technology Institute. He has Masters in Computational Nuclear Science and Engineering and a BSc. in Physics. His research interest includes Instrumentation in Radio Astronomy, Methanol Masers, Radio Interferometry and Computational Modeling.

Marcellin Atemkeng : holds a MSc Computer Sc. and BSc Mathematics and Computer Sc. His research interest includes Networking, Structure Documents, Workflow Systems, Simulation, Signal Correlation Algorithm Techniques, Synthesis Imaging in Radio Interferometry Arrays and Data Reduction.

Theophilus Ansah-Narh : is working as an Assistant Research Scientist at Ghana Space Science and Technology Institute. He has MPhil in Statistics, MPhil Computational Nuclear Science and Engineering and also, BSc. Mathematics and Computer Science. His research interest includes Radio Interferometry, Stochastic Modeling, Bayesian Analysis, Computational Mathematics and Parallel Computing.

 

 

 

 

 

 

 

Beam Pattern

OSKAR Simulator

Very Long Baseline Interferometry (VLBI)

Stokes Parameters

In conclusion, signals with different intensities can be expressed in Stokes parameters I, Q, U and V with I being the total intensity which is formed as a result of autocorrelation likewise V. These intensities generate different beam patterns during observations in the sky. A continuation of this research is to simulate the correlation between the Nkutunse antenna (in Ghana) and MeerKAT (in South Africa) to effectively evaluate how much resolution the new set of baselines bring with the combine instruments.

 

 

 

 

 

 

 

 

 

[1] http://www.oerc.ox.ac.uk/~ska/oskar2/

[2] African VIBI Network: Ghana Antenna Conversion - Background Material, (2011). SKA – SA.

[3] Van Veen, B. D. and Buckley, K. M. (1988). Beamforming: A Versatile Approach to Spatial Filtering, IEEE ASSP MAGAZINE, 04 – 24.

[4] Walker, R. C. (1999). Very Long Baseline Interferometry, Astronomical Society of the Pacific Conference Series, Vol. 180, 433 – 462.

[5] Thompson, A. R., Moran, J. M. and Swenson, G.W. 1986, Interferometry and Synthesis in radio Astronomy (New York: John Wiley and Sons)

[6] Zenus, A., Diamond, P.J., and Napier, P. J. 1995, Very Long Baseline Interferometry and the VLBA Astronomical Society of the Pacific Conference Series, Volume 82 (San Francisco: ASP)

[7] Zensus, A., Taylor, G. B., and Wrobel, J. M. 1998, IAU Colloquium 164: Radio Emission from Galactic and Extragalactic Compact Sources, Astronomical Society of the Pacific Conference, Vol. 144. (San Francisco: ASP).

[8] Lorrain, P. and Corson, D. R. (1970), Electromagnetic Fields and Waves, 2nd ed., W. H Freeman and Co.

[9] Balanis, C. A. (2005). Antenna Theory Analysis and Design, 3rd ed., John Wiley and Sons, INC.