Abstract: A first converter converts an initial attitude in an Euler angle representation into an initial attitude represented by quaternion. An updating unit updates an attitude represented by quaternion by defining the initial attitude represented by quaternion as an initial value, successively substituting output values of the triaxial gyro sensor. A second converter converts the attitude represented by quaternion into an attitude in the Euler angle representation. An angular speed derivation unit derives an angular speed based on a time-dependent change in the attitude in the Euler angle representation. A controller adjusts a period of time for derivation by an initial attitude derivation unit based on a variance value of the output value of the triaxial acceleration sensor or a variance value of the output value of the triaxial gyro sensor, when the speed is lower than a threshold value.

Abstract: A GPS positioning unit acquires GPS positioning data of an object positioned based on a signal from a GPS satellite, and an angular velocity sensor acquires an output signal of the object. A sensitivity coefficient calculation unit sequentially derives a temporary sensitivity coefficient of the angular velocity sensor based on the GPS positioning data and the output signal. The sensitivity coefficient calculation unit derives a sensitivity coefficient for correcting the angular velocity output from the angular velocity sensor, by performing statistical processing on the temporary sensitivity coefficient of the angular velocity sensor that has been sequentially derived. A correlation coefficient calculation unit derives a correlation coefficient based on the GPS positioning data and the output signal. The sensitivity coefficient calculation unit changes a forgetting coefficient to be used when the statistical processing is performed, in accordance with the correlation coefficient.

Abstract: A temperature gradient calculation unit calculates a temperature gradient based on the temperature from the temperature sensor and calculates an average temperature based on the temperature gradient. An offset gradient calculation unit calculates an offset value gradient based on the temperature gradient, the average temperature, and the temporary offset value of the angular speed sensor. A correction value calculation unit calculates the offset value of the angular speed sensor based on the offset value gradient and the temperature gradient.

Abstract: A first converter converts an initial attitude in an Euler angle representation into an initial attitude represented by quaternion. An updating unit updates an attitude represented by quaternion by defining the initial attitude represented by quaternion as an initial value, successively substituting output values of the triaxial gyro sensor. A second converter converts the attitude represented by quaternion into an attitude in the Euler angle representation. An angular speed derivation unit derives an angular speed based on a time-dependent change in the attitude in the Euler angle representation. A controller adjusts a period of time for derivation by an initial attitude derivation unit based on a variance value of the output value of the triaxial acceleration sensor or a variance value of the output value of the triaxial gyro sensor, when the speed is lower than a threshold value.

Abstract: A GPS positioning unit acquires GPS positioning data of an object positioned based on a signal from a GPS satellite, and an angular velocity sensor acquires an output signal of the object. A sensitivity coefficient calculation unit sequentially derives a temporary sensitivity coefficient of the angular velocity sensor based on the GPS positioning data and the output signal. The sensitivity coefficient calculation unit derives a sensitivity coefficient for correcting the angular velocity output from the angular velocity sensor, by performing statistical processing on the temporary sensitivity coefficient of the angular velocity sensor that has been sequentially derived. A correlation coefficient calculation unit derives a correlation coefficient based on the GPS positioning data and the output signal. The sensitivity coefficient calculation unit changes a forgetting coefficient to be used when the statistical processing is performed, in accordance with the correlation coefficient.

Abstract: A temperature gradient calculation unit calculates a temperature gradient based on the temperature from the temperature sensor and calculates an average temperature based on the temperature gradient. An offset gradient calculation unit calculates an offset value gradient based on the temperature gradient, the average temperature, and the temporary offset value of the angular speed sensor. A correction value calculation unit calculates the offset value of the angular speed sensor based on the offset value gradient and the temperature gradient.

Abstract: A GPS measuring unit receives a signal from a GPS satellite and outputs GPS measurement data including at least orientation of an object. An angular velocity sensor outputs angular velocity of the object. An offset value computing unit estimates a running condition of the object on the basis of the measurement data and the angular velocity. The offset value computing unit sequentially derives a temporary offset value of the angular velocity sensor in accordance with the estimated running condition of the object. The offset value computing unit derives an offset value of the angular velocity sensor by executing statistical process on the temporary offset value of the angular velocity sensor. A forgetting factor in the statistical process is changed according to the running condition of the object.

Abstract: A measuring unit obtains measurement data of an object measured on the basis of a signal from a GPS satellite and angular velocity of an object output from an angular velocity sensor. An offset value computing unit estimates a running condition of the object on the basis of the measurement data and the angular velocity. The offset value computing unit sequentially derives temporary offset values while changing combination of the measurement data and the angular velocity in accordance with the estimated running condition of the object and, after that, executes statistical process on the temporary offset values, thereby deriving an offset value. An angular velocity conversion coefficient computing unit sequentially derives temporary angular velocity conversion coefficients on the basis of the measurement data and the angular velocity and, after that, executes statistical process on the temporary angular velocity conversion coefficients, thereby deriving an angular velocity conversion coefficient.

Abstract: A position measuring unit measures measurement data including at least a movement velocity, an accuracy reduction index, and an azimuth on the basis of a signal received from a satellite. A determining unit for a distance determines validity of measurement data and determines whether to derive a distance conversion coefficient using the measurement data determined valid. When the deriving is determined, a distance conversion coefficient calculator derives a distance conversion coefficient. A determining unit for an angular velocity determines an effective range for an integration value of an output value from an angular velocity sensor over a predetermined period on the basis of a movement velocity included in measurement data, and determines whether to derive an angular velocity conversion coefficient on the basis of the effective range and the integration value of the output values over the predetermined period.

Abstract: A measuring unit obtains measurement data of an object measured on the basis of a signal from a GPS satellite and angular velocity of an object output from an angular velocity sensor. An offset value computing unit estimates a running condition of the object on the basis of the measurement data and the angular velocity. The offset value computing unit sequentially derives temporary offset values while changing combination of the measurement data and the angular velocity in accordance with the estimated running condition of the object and, after that, executes statistical process on the temporary offset values, thereby deriving an offset value. An angular velocity conversion coefficient computing unit sequentially derives temporary angular velocity conversion coefficients on the basis of the measurement data and the angular velocity and, after that, executes statistical process on the temporary angular velocity conversion coefficients, thereby deriving an angular velocity conversion coefficient.

Abstract: A GPS measuring unit receives a signal from a GPS satellite and outputs GPS measurement data including at least orientation of an object. An angular velocity sensor outputs angular velocity of the object. An offset value computing unit estimates a running condition of the object on the basis of the measurement data and the angular velocity. The offset value computing unit sequentially derives a temporary offset value of the angular velocity sensor in accordance with the estimated running condition of the object. The offset value computing unit derives an offset value of the angular velocity sensor by executing statistical process on the temporary offset value of the angular velocity sensor. A forgetting factor in the statistical process is changed according to the running condition of the object.

Abstract: A position measuring unit measures measurement data including at least a movement velocity, an accuracy reduction index, and an azimuth on the basis of a signal received from a satellite. A determining unit for a distance determines validity of measurement data and determines whether to derive a distance conversion coefficient using the measurement data determined valid. When the deriving is determined, a distance conversion coefficient calculator derives a distance conversion coefficient. A determining unit for an angular velocity determines an effective range for an integration value of an output value from an angular velocity sensor over a predetermined period on the basis of a movement velocity included in measurement data, and determines whether to derive an angular velocity conversion coefficient on the basis of the effective range and the integration value of the output values over the predetermined period.