The effect of magnetometer and accelerometer errors on the predicted trajectories of boreholes surveyed by EMS instruments

A wide range of borehole surveying instruments is available. They provide data (such as borehole direction and dip,<br>and the components of the local magnetic and gravitational field) at pre-determined downhole stations. A number of<br>algorithms are used to convert these data to 3D coordinates in the relevant reference systems (Orpen, 2005). Electronic<br>Multi-Shot (EMS) type borehole navigators are used extensively within the hard rock mining environment to determine<br>the trajectories of boreholes, especially as the alternatives (optical deflection and inertial navigation based systems, e.g.<br>gyros) are seen as being either too expensive, or don’t fit the smaller diameter boreholes.