恒虚警下复合载波导航信号联合捕获方法

A Joint acquisition method for navigation signal based on compound carrier with constant false alarm rate

复合载波导航信号(NSCC)作为一种新型的导航增强信号体制,其独特的多载波结构和灵活的体制参数设计,使之具备良好的导航增强效能。同时,以上典型信号特征也使得传统的导航信号同步算法对其不再适用。针对复合载波导航信号结构特征和体制参数设计特点,提出了一种基于多载波架构的恒虚警联合捕获方法。该方法利用复合载波导航信号各子载波信号功率进行自适应检测门限设置,并利用各子载波频点间隔信息进行并行检测,然后根据联合策略做出判决,提升了捕获性能和捕获效率。理论分析及仿真实验均表明,在低信噪比(SNR)情况下,本文所提出的联合捕获方法的捕获性能明显优于单载波捕获算法,并缩短了平均捕获时长。

Navigation signal based on compound carrier （NSCC）, as a novel signal structure for navigation augmentation, has a special multi-carrier structure and flexible structure parameters, which enable it to possess significant efficiency of navigation augmentation. However, due to the special structure of NSCC, the traditional acquisition algorithms cannot be applied to the NSCC. In this paper, based on the characteristics of NSCC, we propose a kind of joint acquisition method with constant false alarm rate for multi-carrier system by utilizing the known information of NSCC. In this method, the adaptive detection threshold of sub-carrier is set respectively according to its power. Besides, the joint detection is achieved by using the sub-carrier frequency interval to improve the acquisition performance and efficiency. Both the theoretical analysis and simulation results illustrate that the acquisition performance of this method beats the single-carrier signal and the acquisition time is also efficiently reduced as well.