To calculate a speed or displacement with high accuracy while suppressing an increase in data processing volume.SOLUTION: A GNSS data editing unit generates data for GNSS attitude angle estimation and data for GNSS speed estimation using first GNSS data based on the GNSS signal received by a first antenna and second GNSS data obtained on a shorter cycle than the first GNSS data on the basis of the GNSS signal received by a second antenna. An attitude angle computation unit estimates an integrated attitude angle using the IMU angle speed outputted from an IMU and the data for GNSS attitude angle estimation. A speed computation unit estimates an integrated speed using the IMU acceleration outputted from the IMU, the data for GNSS speed estimation, and the integrated attitude angle.SELECTED DRAWING: Figure 1
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