RFI mitigation strategies for phased-array SKA concepts

Abstract

Although the Square Kilometer Array (SKA) will be located in remote areas, astronomical observations may be hampered by man-made radio frequency interference (RFI). In this paper we consider possible interference mitigation options in relation to complexity and cost. As RFI signals will be present even in remote places (e.g. satellite signals and signals from airplanes), SKA design has to consider and take into account e ects of interference. These e ects may concern linearity of the analogue and digital signal processing chain, such as the number of (analogue-digital converter, ADC) bits, low-noise amplifier (LNA) dynamic range, and (fibre) signal transport dynamic range. RFI signals may also influence the astronomical end-product as additive noise with certain spectral, temporal and spatial properties. As these properties usually di er from the astronomical signal properties, interference can in principle be mitigated. Mitigation however, always includes a cost both in terms of money and often also in terms of signal integrity. RFI mitigation counter measures therefore should be balanced in the sense that the cost of including RFI measures in the design is justified in terms of regained spectrum.