North seeking gyro survey tools
North Seeking gyro directional drilling survey tools provide substantially more accurate survey data than conventional gyro tools. In the conventional gyroscopic survey tool, the gyro is oriented to a known reference direction or foresight.
A North Seeking gyro directional drilling survey tool uses a gyro to reference itself to True North, eliminating the need for a foresight. The foresight reference uncertainty and possible reading uncertainties are replaced by an operator independent North seek uncertainty. This referencing to True North is called gyrocompassing. It is based on the measurement of the horizontal component . . .