多普勒频率变化率快速最大似然估计辅助的高动态载波跟踪环路

发布时间：2018-04-03 01:34

本文选题：载波跟踪　切入点：高动态　出处：《电子与信息学报》2014年03期

【摘要】：高动态环境下接收信号含有较大的多普勒频率及其变化率,传统载波跟踪方法难以在高动态应力和跟踪精度两方面取得较好折中,针对这一问题该文提出一种多普勒频率变化率快速最大似然估计方法,并利用估计值辅助载波跟踪环路。首先指出了多普勒频率及其变化率的最大似然估计可等效采用分数阶傅里叶变换(FrFT)来实现;其次,针对频率及其变化率2维搜索运算量大的问题,提出一种瞬时自相关与分段离散傅里叶变换(DFT)求相位差相结合的频率变化率估计方法,根据粗估值可大大缩小搜索范围;最后,利用估计值辅助载波跟踪环路,降低动态应力,提高跟踪精度。理论分析与计算机仿真表明,在典型高动态参数条件下,输入信噪比为-30 dB时,搜索运算量降为原来的5.25%,输出频率的均方根误差仅为8.46 Hz/s,和传统载波跟踪方法相比,灵敏度提高3 dB以上。
[Abstract]:In high dynamic environment, the received signal has a large Doppler frequency and its rate of change, so it is difficult to achieve a good compromise between high dynamic stress and tracking accuracy by traditional carrier tracking method.To solve this problem, a fast maximum likelihood estimation method for Doppler frequency change rate is proposed, and the estimator is used to assist the carrier tracking loop.It is pointed out that the maximum likelihood estimation of Doppler frequency and its rate of change can be realized by fractional Fourier transform (FrFT) equivalent.A frequency change rate estimation method combining instantaneous autocorrelation with phase difference of discrete Fourier transform (DFT) is proposed. The search range can be greatly reduced according to the rough estimation. Finally, the estimation value is used to assist the carrier tracking loop to reduce the dynamic stress.Improve tracking accuracy.Theoretical analysis and computer simulation show that when the input SNR is -30 dB, the search operation is reduced to 5.25 and the root mean square error of the output frequency is only 8.46 Hz / s, compared with the traditional carrier tracking method.The sensitivity is improved by more than 3 dB.
【作者单位】：北京理工大学信息与电子学院;
【基金】：教育部博士点基金(20121101130001) CAST重点基金(201215) 北京市自然科学基金(4112051)资助课题
【分类号】：TN911.7

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