Page 39 - 《应用声学》2020年第5期

第 39 卷 第 5 期 Vol. 39, No. 5
2020 年 9 月 Journal of Applied Acoustics September, 2020

⋄ 研究报告 ⋄

宽带多普勒测速技术中的发射信号 ∗

黎美琪 1,2 王长红 1,3 邓 锴 1,3†
(1 中国科学院声学研究所 北京 100190)
(2 中国科学院大学 北京 100049)
(3 北京市海洋声学装备工程技术研究中心 北京 100190)

摘要：声波信号作为系统测速的载体，直接影响测速性能，是多普勒测速技术的关键。研究了不同发射信号的
频谱特性及基于复协方差法的多普勒频移测量误差。一般假设二相编码信号频谱关于载频对称，但实际上其
频谱为不关于载频对称的双边谱，不对称程度由不对称系数量化。不对称系数越小，测频偏差、标准差均越小，
即测频性能更佳。仿真实验表明，在不考虑波束开角的点回波模型下，差分重复伪随机 Blackman 码元幅度调
制编码信号与常用的非差分重复伪随机二相编码信号相比：不对称系数低 3 个数量级；信号频带同带宽内信噪
比在 0 ∼ −10 dB 范围内测频标准差约下降 2% ∼ 20%；信噪比高于 10 dB 时相对测频偏差约小 5‰ ∼ 6‰。
关键词：多普勒测速；宽带编码信号；频谱特性；误差分析
中图法分类号: TN911.7 文献标识码: A 文章编号: 1000-310X(2020)05-0681-09
DOI: 10.11684/j.issn.1000-310X.2020.05.005

The transmit signal in broadband Doppler velocimetry technology
LI Meiqi 1,2 WANG Changhong 1,3 DENG Kai 1,3

(1 Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China)
(2 University of Chinese Academy of Sciences, Beijing 100049, China)
(3 Beijing Engineering Technology Research Center of Ocean Acoustic Equipment, Beijing 100190, China)
Abstract: As the carrier of system velocimetry, acoustic signal directly affects the velocimetry performance,
which is the key to Doppler velocimetry technology. The spectral characteristics of different transmitted
signals and the Doppler shift measurement error based on complex covariance method are studied. It is
generally assumed that the spectrum of the two-phase coded signal is symmetric about the carrier frequency,
but in fact its spectrum is a bilateral spectrum that is not symmetric about the carrier frequency, and the
degree of asymmetry is quantified by the asymmetry coefficient. The smaller the asymmetry coefficient is, the
smaller the Doppler shift measurement bias and standard deviation are, that is, the Doppler shift measurement
performance is better. Simulation experiments show that the differential repeated pseudo-random Blackman
symbol amplitude modulation coded signal is compared with the commonly used non-differential repeated
pseudo-random two-phase coded signal under the point echo model without considering the beam angle: the
asymmetry coefficient is three orders of magnitude lower; when the SNR within the same frequency band of
the signal is within the range of 0 ∼ −10 dB, the Doppler shift measurement standard deviation is reduced by
about 2% ∼ 20%; when the SNR is higher than 10 dB, the relative Doppler shift measurement bias is about
5‰ ∼ 6‰ smaller.
Keywords: Doppler velocimetry; Broadband coded signal; Spectral characteristics; Errors analysis

2019-11-18 收稿; 2020-03-31 定稿
国家重点研发计划项目 (2017YFC1403404)
∗
作者简介: 黎美琪 (1995– ), 女, 江西九江人, 硕士研究生, 研究方向: 信号与信息处理。
† 通信作者 E-mail: dengk@mail.ioa.ac.cn