【摘要】 为降低Ka频段卫星移动通信中的信道误码率,该文基于π/4-DQPSK调制方式推导了一种多普勒频偏的捕获方法。在跟踪阶段利用自回归模型对有色噪声建模,并利用卡尔曼算法对噪声进行滤波。仿真结果表明:随着时间的推移,参数估计值与实际值之间的误差均方值越来越小,且噪声模型的参数在很短的时间内就达到较高的估计精度;在多普勒频偏跟踪阶段,随着跟踪时间的加长,多普勒频偏的估计值逐渐收敛到理论值;该文提出的多普勒频偏跟踪算法切实可行,卡尔曼算法保证了跟踪阶段频偏估计值的稳态收敛。更多还原

【Abstract】 In order to reduce the channel error rate of Ka-band mobile satellite communication system,the paper deduces a method of rapid Doppler frequency offset acquisition on the basis of π/4-DQPSK modulation.In the tracking phase,an autoregressive model is used to establish the mode of colored noise,and the Kalman algorithm is used to filter it.The simulation results show that the mean-square value between the estimated value and practical value becomes smaller along with the time and the parameters of the noise mode reaching high precision in a short time.In the Doppler frequency offset tracking,the estimated value converges to the theoretical value along with tracking time.The Doppler frequency offset tracking algorithm put forward here is feasible and the Kalman algorithm ensures the estimated value converges reliably in the period of the tracking phase.更多还原