Digital beamforming techniques applied to satellite-based AIS receiver

This article investigates using DBF onboard AIS satellites with the objective to increase the signal-to-interference-plus-noise ratio (SINR) so that the number of decoded AIS messages can be increased. A DBF system is based on an array of antenna elements acting as independent receivers that capture radio frequency (RF) signals. These signals are converted into two digital streams of baseband I and Q signals, and then they are weighted (by changing their amplitude and phase) so that when they are combined together (summed) they create a desired output (i.e., the AIS signal of interest with a high level of SINR). The article presents an antenna array with a single-element radiation pattern optimized to mitigate interference. Based on this antenna array, static and adaptive DBF techniques have been compared in terms of SINR increase and system complexity (i.e., need for a large antenna, computational complexity of an adaptive DBF technique, etc.).