LFMCW主动导引头数字接收的设计

Design of a Digital Receiving for LFMCW Active Seeker

针对线性调频连续波(LFMCW)主动导引头的零中频回波特征,提出了一种基于数字正交混频和高抽取率数字滤波的数字接收方案。与传统模拟接收方案相比,数字接收不仅降低了硬件实现的复杂度和体积,解决了I/Q通道幅相不一致的问题,而且可以显著减小后级信号处理的数据量。另外,通过数字接收频率和滤波带宽的实时调整,可以利用同一数字接收结构满足导引头目标搜索和跟踪的不同需求。系统实现表明该方案结构紧凑、控制灵活并且性能稳定,能够满足弹载小型化、低功耗和高可靠性的要求。

A digital receiving scheme based on quadrature mixing and high sampling density digital filtering is presented according to zero intermediate frequency （IF） echoes characteristic of linear frequency modulated continuous wave （LFMCW） for active seeker. Comparing with traditional analogue receiving, the digital receiving scheme can not only significantly reduces complexity and size of hardware and data amount in flowing signal processing, but also can solve inconsistency of amplitude/phase between I/Q chau nels which often occur in analog circuits. Additionally, through real-time adjustment to digital receiving frequency and filtering bandwidth, a digital receiving structure is obtained; it can meet requiremcnts of seeker both for target searching and tracking. Implementation of the system shows that the digital receiving scheme can meet miniaturization, low power consumption and high reliability requirements for missilebrone application due to its advantages such as compact structure, easy to control and stable performance.