Browsing by Author "De Beer, Mourits"

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    Wideband Direction Finding of RFI for MeerKAT
    (Stellenbosch : Stellenbosch University, 2017-03) De Beer, Mourits; Wiid, Gideon; Davidson, David; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: The Karoo desert in the Northern Cape of South Africa is currently host to the MeerKAT radio telescope { a precursor facility for the Square Kilometre Array (SKA) project. The area was selected due to its natural quietness from man-made sources of radio-frequency interference (RFI), as the telescope site needs to uphold demanding electromagnetic compatibility (EMC) standards in order to perform sensitive radio astronomy observations. It is therefore necessary that the facility monitors the spectrum across MeerKAT's operational bandwidth to identify the presence of noise sources that may compromise the integrity of future measurements. This thesis presents the design and simulation of a direction finding (DF) solution that will prove to be an essential means of locating and mitigating on-site or outside sources of interference. The asymptotic conical dipole (ACD) antenna is implemented with a 3D-printed plastic design, coated in metal to achieve an impedance bandwidth greater than 100:1. Four units of these designs are manufactured for use in a multi-receiver system, which applies a phase correlation DF algorithm to estimate the bearing of an impulse source. The accuracy of arbitrary antenna configurations is investigated by simulation to evaluate the performance under noisy conditions. Field measurements are conducted that verify the simulated angular resolution of the system, which obtains source angle estimates within ±2:5° accuracy.