Abstract: The attitude of an excavating part during excavation is accurately measured. A measuring apparatus of the present invention executes an attitude estimating processing and a phase correction amount calculating processing. The phase correction amount calculating processing calculates an offset between a gravity tool face and a magnetic force tool face, and sets the calculated offset as an estimated offset. The attitude estimating processing sets the gravity tool face based on the acceleration data as a measured gravity tool face, the magnetic force tool face based on the magnetic field data as a measured magnetic force tool face, a difference between an offset between the measured gravity tool face and the measured magnetic force tool face and the estimated offset as a phase correction amount, and data obtained by correcting the magnetic field data with the phase correction amount as corrected magnetic field data, and determines the attitude based on the acceleration data and the corrected magnetic field data.

Abstract: Canister-shaped magnetic reinforcing elements 31, 32 made of a ferromagnetic material having a Curie temperature higher than magnetic yokes 11, 12 are provided inside the magnetic yokes 11, 12. The inner periphery 31a, 32a of an opening in each of the magnetic reinforcing elements 31, 32 is opposed to the outer periphery 51a, 52a of each of pole piece tops 51, 52. A torquer coil 61, 62 is located between the inner periphery 31a, 32a of the opening in each of the magnetic reinforcing elements 31, 32 and the outer periphery 51a, 52a of each pole piece top 51, 52. The magnetic reinforcing elements 31, 32 provided inside the magnetic yokes 11, 12 form independent magnetic circuits. Since the magnetic reinforcing elements 31, 32 have a Curie temperature higher than the magnetic yokes 11, 12, a high accuracy of acceleration measurement in a high-temperature range can be achieved.

Abstract: Canister-shaped magnetic reinforcing elements 31, 32 made of a ferromagnetic material having a Curie temperature higher than magnetic yokes 11, 12 are provided inside the magnetic yokes 11, 12. The inner periphery 31a, 32a of an opening in each of the magnetic reinforcing elements 31, 32 is opposed to the outer periphery 51a, 52a of each of pole piece tops 51, 52. A torquer coil 61, 62 is located between the inner periphery 31a, 32a of the opening in each of the magnetic reinforcing elements 31, 32 and the outer periphery 51a, 52a of each pole piece top 51, 52. The magnetic reinforcing elements 31, 32 provided inside the magnetic yokes 11, 12 form independent magnetic circuits. Since the magnetic reinforcing elements 31, 32 have a Curie temperature higher than the magnetic yokes 11, 12, a high accuracy of acceleration measurement in a high-temperature range can be achieved.