• Probe (Sensor Package)The probe, or directional sensor package, is heart of the system. It has 3-accelerometers (which measures inclination) and 3-magnetometers (which measures magnetic north or azimuth). The guidance system shall be accurate to ± 2% of the vertical depth of the pilot hole at sensing position and accurate within 1.5 m horizontally. The tracking system shall be calibrated, before the start of the drill and the possible magnetic interference shall be checked prior to drilling.• Surface ComputerThe surface computer receives the sensor data from down hole and calculates inclination, azimuth and tool face readings. The calculated results are then printed out or sent to the driller’s remote display during drilling.• Drillers Remote DisplayThe driller’s remote display is placed in the operator’s cab on the drilling rig. It displays the Azimuth, Inclination and tool face orientation of the Bottom Hole Assembly (BHA).