| 摘要 |
PURPOSE:To improve the accuracy in controlling frequency by accurately measuring an original oscillation frequency. CONSTITUTION:The frequency of first and second electric waves is measured simultaneously by first and second Doppler frequency measurement parts 13 and 1 and the amount of change of the original oscillation frequency is calculated based on the measurement value of the frequency of the first and second electric waves, thus calculating the amount of change of the original oscillation frequency without using Doppler frequency including a track prediction error. |
