BOC信号捕获算法硬件实现的探讨.pdf

CSNC2010 第一届中国卫星导航学术年会 北京 BOC 信号捕获算法的硬件实现技术 滕达 崔晓伟 陆明泉 冯振明 (清华大学电子工程系，北京, 100084) 摘 要: BOC 信号调制方式在新的导航系统中开始流行的一种伪随机码调制方式。被广泛的应用在诸如 GPS 系统中的 M 码 信号，Galileo 的E1、E2、E6 频段中多种BOC（m,n）码信号等。与传统的BPSK调制信号的捕获结果不同，BOC码信号的 捕获结果的相关峰更加尖锐，这使得捕获与跟踪的结果更加精确。但是在噪声较大的情况下，由于 BOC 码调制特点所带 来的相关峰多值的问题会引起捕获过程中的误捕及跟踪过程的误锁等现象。目前学术界已经提出了针对 BOC 码捕获过程 中几种去多峰的捕获算法。本文将提出针对这些特殊算法的硬件实现结构。本文还针对BPSK与BOC码捕获过程中算法硬 件实现与新结构，提出一些新的探讨。这些新结构与探讨主要包括内存格式的伪随机码的使用，NCO硬件实现的结构优化， 以及传统捕获方式的相关器结构与FFT算法捕获的硬件结构的比较。 关键词：伪随机码；BOC调制；捕获算法；硬件实现 Research on hardware implementation of BOC acquisition method Teng Da, Cui Xiaowei, Lu Mingquan, Feng Zhenming (Department of Electronic Engineering, Tsinghua University, Beijing 100084, China) Abstract: BOC modulation for DSSS signal is being prevalent in new GNSS systems. It has been decided to use as the M code in GPS system, and some BOC(m, n) signal has been decided to use as E1, E2 and E6 in Galileo system. The most difference between BOC and BPSK signals is their acquistion consequence which becomes sharper than the correlation of BPSK. Although it can be better in the tracking stage, the many peaks of the BOC correlation results may take a false result or the latter false lock when noise becomes occupied. The proposed methods will be introduced in this paper. The hardware frame of the acquisition will also be discussed, including some further thoughts about the mem-code and NCO hardware optimized and the hardware frame comparison between the correlator and the acquisition using FFT method. Key words: Pseudo-Noise Code; BOC Modulation; Acquisition Algorithm; Hardware Realization. 1 引言 随着 PSK 调制在 GNSS 系统中的成功应用，GNSS 系统在进行更多的码调制方式的研究。在进行源误 差带来误差减小方法的研究变得较为成熟后，多径与噪声的研究变得越来越多。同时，