This paper proposes a calibration and compensation method of an inertial measurement unit (IMU) composed of two dynamically tuned gyros (DTGs) and three quartz accelerometers. Considering the DTG IMU for the position and orientation system (POS) used in the air remote sensing, it is found that the gyro scale factor has a hyperbolic relationship with the input angular rate and a linear relationship with the temperature shown from the experiments. Based on this, the equations of the gyro scale factor, the input angular velocity and the temperature are established by applying the least-square fit. Next, a hybrid multiposition calibration method of the IMU is given to estimate the error model parameters and compensate system errors. At last, a laboratory rate test and a car-mounted experiment are carried out to assess the efficiency of the proposed method. It is demonstrated from the experiment results that the attitude accuracy of the DTG POS can be improved with the calibration based on the compensation of scale factor errors.