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One of the old challenges in navigation is to find the direction of vehicles. For a precise navigation, having some prerequisites about major directions (North, South, East and West) is necessary. Nowadays detection of true north (intersection between earth´s rotation axis and its surface) plays an important role in navigation and it is one of the most prominent parameters in both military and civil tasks like tunneling. There are different techniques of north finding that mainly can be considered as: inertial, hybrid and non-inertial methods. Hybrid is the combination of inertial and non-inertial methods. Inertial navigation system needs to initial alignment for north detection that includes finding the horizon and north direction. These two processes happen in two different steps: leveling and gyrocompassing. In this work, the inertial sensors consist of three gyroscopes and three accelerometers are going to be used. This book mainly concentrates on the developing algorithm for a new gyrocompass for TBM navigation (algorithm will calculate azimuth from raw data of gyrocompass) and some errors and data analysis will be shown and some filters will be used for better solutions.

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Kianoosh Nazari, Master of Science (M.Sc.) - Geomatics, University of Applied Science, Karlsruhe, Germany. Bachelor of Science (B.Sc.) - Surveying Engineer, Tabriz University, Iran. Associate degree, Surveying, Zanjan university, Iran. Geomatics engineer in Administrative District Office in Germany.

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