Abstract: A method and a system for determining the position of a drill bit are presented. The method comprises determining positions of seismic wave detectors, recording seismic waves generated at the drill bit, identifying events at the drill bit, determining a plurality of relative positions of the drill bit, and determining, based at least partly on a starting position and a sum of the relative positions, an absolute position of the drill bit. The method further comprises determining a position of the drill bit at a second event in relation to a position of the drill bit at a first event, and determining a second seismic wave propagation velocity between the drill bit and at least one of the detectors, based at least partly on the determined position of the drill bit at the second event.

Abstract: The present invention relates to a method for estimating the position and trajectory of a drill during drilling of boreholes in rock. The method comprising the steps of determining the starting position of the drill bit and recording the received transient seismic waves generated by the drill on impact, and estimating the difference in arrival time between events. From these, the relative distances, between the positions of the drill bit at different events are calculated and from these the present position is calculated.