介绍了国际民航组织(ICAO)规范的单脉冲二次雷达(MSSR)模式AC和模式S应答信号的信号格式。首先,基于多个民航项目分析了传统的上升沿估计方法对MSSR应答信号的到达时间(TOA)的估计,并在此基础上对其进行改进,提出了自适应门限的TOA估计方法;然后,分析了采用匹配滤波的最优TOA估计方法;最后,通过仿真实验对三种方法进行了对比。实验结果表明,文中提出的自适应门限TOA估计方法性能优于传统的上升沿TOA估计方法,略次于匹配滤波方法。但所提方法不需要进行复杂的匹配滤波操作,计算量小、实时性好,具有一定的工程价值,且更适用于对应答信号解交织。

The ICAO standard signal format of MSSR Mode AC and Mode S is introduced in this paper. Estimation of time-of-arrival (TOA) using pulse rising edge of MSSR signal in several projects of civil aviation is analyzed. And a new improved TOA estimation method based on adaptive threshold is proposed. Then best statistical TOA estimation method using matched filtering is discussed, and finally the three methods are compared through simulation. Experimental results show that the proposed TOA estimation method depended on adaptive threshold is better than traditional TOA estimation method, but is not as accurate as the matched filtering method. However, the proposed method does not require complex matched filtering operation and less computation is needed. So the new method has certain engineering value, and is more suitable for de-interleaver of MSSR reply signal.

TN959. 2