ARTIFICIAL SATELLITE

PROBLEM TO BE SOLVED: To provide an artificial satellite capable of accurately estimating frequency offset at early stage under such circumstances that a large frequency offset may occur due to Doppler phenomenon.SOLUTION: The artificial satellite is provided with a Doppler compensation circuit, which includes: a Doppler estimation part configured to acquire a reception electric power level for receiving wave and time-variation of the reception electric power level and carrying out a series of calculation processing the Doppler frequency of the satellite based on the reception electric power level for the receiving wave and the time-variation of the reception electric power level to output the same as an estimated Doppler frequency; and a multiplication part configured to offset the local frequency by the estimated Doppler frequency by multiplying the estimated Doppler frequency and the signal of local frequency for demodulation.SELECTED DRAWING: Figure 1 【課題】ドップラー現象などにより周波数オフセットが大きく生じる環境下で、高精度な周波数オフセット推定を早期に実施可能に構成された人工衛星を提供する。【解決手段】人工衛星に、受信波の受信電力レベルと該受信電力レベルの時間変動を取得し、受信波の受信電力レベル及び受信電力レベルの時間変動に基づいて該衛星のドップラー周波数を導出処理して推定ドップラー周波数として出力するドップラー推定部と、推定ドップラー周波数と復調用のローカル周波数の信号を掛け合わせることにより、ローカル周波数を推定ドップラー周波数分オフセットさせる乗算部と、を含むドップラー補償回路を設ける。【選択図】図１