摘要
给出了统一扩频、统一信道模式的中频数字化扩频测距系统的实现方案。该系统的载波与伪随机码的捕获采用了FFT辅助捕获技术,载波的跟踪采用了数字CPAFC环路牵引、数字COSTAS环路精确跟踪技术,可以有效克服多普勒频移对系统性能的影响。GOLD码跟踪采用的是数字DLL环路,利用该扩频码与截断m序列之间具有的同速率、倍周期的关系,在GOLD码同步后引导截断m序列快速同步。讨论了实现1ns恒分辨率、误差为0.01chip的测距方法与测量数据的"置中值"链接方法。
An IF digital design of unified spread spectrum and unified channel ranging system is provided. In digital implementation, the Flail estimate algorithm is used for carrier and pseudo-random code capture, CPAFC loop and COSTAS loop are used for tracking, and digital DLL loop is used for GOLD code tracking. These technologies can effectively reduce the influence of Doppler shift to the system performance. After GOLD code synchronization,the relationship of same-rate and multiple-cycle between GOLD code and truncated m sequence is used to guide truncated m sequence for rapid synchronization. Finally, a ranging method achieving Ins constant resolution and 0.01 chip error and a data link method of ＂Median Values＂ are discussed.
出处
《无线电工程》
2009年第1期49-50,64,共3页
Radio Engineering
