Speaker
Description
Software Defined Radio (SDR) platforms have emerged as cost-effective solutions for direction finding applications, offering flexibility and accessibility compared to traditional hardware-based systems. Direction finding algorithms, particularly those employing phase-based techniques such as interferometry and beamforming, require precise phase and amplitude coherence between receiver channels. However, commercial SDR devices exhibit inherent variations in local oscillator phases, filter responses, and analog front-end characteristics that compromise inter-channel coherence. The challenge lies in characterising and compensating for these systematic errors within the GNU Radio framework. Traditional calibration approaches often require specialised equipment, making field deployment complex. This work addresses the critical problem of coherent channel calibration in multi-channel SDR direction finding systems implemented using GNU Radio. It includes a comprehensive GNU Radio flowgraph implementation for real-time coherent channel calibration. It leverages built-in GNU Radio blocks and customised signal processing blocks to implement phase and amplitude correction algorithms that can operate with readily available calibration sources.
