地空衰落信道下JTIDS信号信噪比盲估计

针对地空衰落信道下联合战术信息分发系统（JTIDS）信号信噪比的估计问题，提出了一种适用于单脉冲和双脉冲时隙结构JTIDS信号的接收信噪比盲估计方法。首先，利用信道实时最大时延粗估计值确定无符号间干扰的数据区间；其次，基于JTIDS信号脉冲时隙结构中静默时间的保护间隔特性估计噪声功率；最后，根据选定区间数据的自相关函数估计接收信号的信号功率，从而估计出接收链路的信噪比。仿真实验结果表明，取单时隙样本长度时，在巡航、起降两种空中平台状态下，提出估计方法在较宽信噪比范围内具有良好的均方误差估计性能，可满足JTIDS系统的信噪比估计需求。

Blind SNR estimation of JTIDS signals over air-ground fading channel

For the signal-to-noise ratio(SNR) estimation of Joint Tactical Information Distribution System(JTIDS) over air-ground fading channel,a blind SNR estimation method is presented which can adapt to signal timeslot structures of standard double pulse and single pulse.Firstly,the real channel maximum delay is roughly estimated to determine the data interval which is free of inter-symbol interference(ISI).Secondly,the noise average power is estimated by utilizing the guard interval characteristic of silence time.Finally,the signal average power is estimated by computing the autocorrelation values of data in the determined interval and the SNR estimation of the received signals is realized.The simulation results demonstrate that the proposed method has better mean square error(MSE) performance for a wide range of SNRs with air-ground fading channels of en-route,arrival and takeoff,and sample length of single time-slot.The proposed method can satisfy the SNR estimation needs of JTIDS.