This book is about my MSc dissertation. The project is about using a single three-axis seismometer to provide bearing estimates to footstep detection. The technique is carried out by cheap low power sensor nodes, which measures the ground vibrations in three perpendicular directions at the same time and a response on each of the two perpendicular, horizontal axes that is directly related to the angle of approach of the wave. This project focuses on the algorithm development for the seismic bearing estimation process. The report describes signal generation and algorithm design procedure during the algorithm development for ideal and simulate seismic signals, and displays the testing results to verify the availability of the developed algorithm.