Sensor error calculating device, attitude angle calculating apparatus, method of calculating sensor error and method of calculating attitude angle

An attitude angle calculating apparatus, comprising:

• a sensor error calculating device comprising:
• processing circuitry configured to:
• calculate a GNSS attitude angle based on positioning signals of a GNSS,
• calculate a GNSS geomagnetism based on the GNSS attitude angle, and
• estimate a sensitivity error, a misalignment error and a bias error of a magnetic sensor by using a magnetic detection value of the magnetic sensor and the GNSS geomagnetism, wherein
• the processing circuitry is further configured to:
• correct the magnetic detection value by using the sensitivity error, the misalignment error and the bias error of the magnetic sensor,
• calculate an azimuth by using the error-corrected magnetic detection value,
• calculate a backup azimuth by using the GNSS attitude angle,
• determine a reliability of the azimuth by using the azimuth and the backup azimuth,
• determine that, when the azimuth is substantially equal to the backup azimuth, the azimuth is reliable, and output the azimuth when the azimuth is determined as reliable, and
• determine an integer bias to be used for the calculation of the GNSS attitude angle, the integer bias being determined by using the outputted azimuth.