塔康包络检测与方位估计算法研究

On TACAN Envelope Detection and Azimuth Estimation Algorithm

采用中频数字化技术的塔康视频信号是离散的脉冲调幅信号,含有大量随机填充脉冲,占空比大。首先,针对峰值搜索提取包络的方法在低信噪比环境下效果差,提出一种新的数字包络检测算法,设计与脉冲相匹配的滤波器,通过检测匹配滤波器输出的最大相关峰值确定脉冲到达时刻,拟合整个脉冲估计其峰值得到包络信号;然后,用最小二乘算法拟合包络估计方位,通过残差分析以一定置信度剔除粗差;最后,对连续k个方位参数数据平滑得到最终的结果。在装备模拟器上的仿真实验表明,所提方法在0 dB功率信噪比下,能有效检测包络、估计方位信息,估计误差小于0.5°,满足系统精度要求。

TACAN video signal based on Intermediate Frequency （ IF） digital technique is a discrete Pulse Amplitude Modulation （ PAM） signal,which contains plenty of random filling pulses with large duty ratio . Considering that the envelope extraction method through searching the pulse peaks is not effective at low SNR,a novel method of digital envelope detection was proposed .According to the definitive signal format,a matched filter was designed to determine the arrival time of pulse by detecting the maximum correlation peak .The pulse peak was estimated to get the envelop signal by fitting the whole pulse .Secondly,least square algorithm was used to estimate the bearing parameter .In order to reduce and restrain outliers,intolerable errors were eliminated on the basis of confidence through residual analysis .At last,the final result was obtained by smoothing acquired k bearing parameters .Its effectiveness was verified by the experiment results .Under the power SNR of 0 dB,the estimation error is less than 0.5＆#176;,which meets the requirement of TACAN system .