﻿ 基于海底线列阵的水下目标高精度测向方法
 舰船科学技术  2020, Vol. 42 Issue (10): 171-174    DOI: 10.3404/j.issn.1672-7649.2020.10.033 PDF

Method of high precision azimuth estimation for underwater target based on submarine linear array
PENG Shui, SUN Xiang-qian, SU Jun
No. 91388 Unit of the PLA, Zhanjiang 524000, China
Abstract: Method of high precision azimuth estimation for underwater target based on submarine linear array is researched. Performance of beamforming technology for MVDR is simulated. The performance test of linear array of 128 element on the sea is studied. After position calibration test of array, error analysis of azimuth estimation at different direction is completed. The test and simulated results match very well. When the source level is 119 dB, and distance below 5 km, then error of azimuth is less than 0.5°. The results of research implied a great future for application of submarine linear array.
Key words: submarine linear array     high precision     azimuth estimation     test on the sea
0 引　言

1 MVDR近场波束形成

MVDR是改进的一种高分辨波束形成方法，称之为最小方差无失真响应（Minimum Variance Distortionless Response）。对于大孔径线列阵而言，很多情况下是在近场区域完成测量。本文主要介绍基于MVDR的近场波束形成算法，用于提高测向精度。

 ${s_l}\left( t \right) = \frac{1}{{{R_l}}}{s_l}\left( {t - \frac{{{R_l}}}{c}} \right)\text{。}$ (1)

 ${{X}}\left( {{t}} \right) = \sum\limits_{k = 1}^K {{{{a}}_{{k}}}} {{{s}}_{{k}}}\left( {{t}} \right) + {{n}}\left( {{t}} \right)\text{，}$ (2)

 ${{{a}}_{\bf{k}}} = \left[ {{e^{ - j\omega \frac{{{d_{1k}}}}{c}}},...,{e^{ - j\omega \frac{{{d_{Mk}}}}{c}}}} \right]\text{，}$ (3)

MVDR波束形成器是使对准的目标信号以单位响应通过，而同时使总的输出功率达到最小来实现主瓣的约束和对干扰的抑制，对应的最优权矢量为：

 ${{\bf{w}}_{opt}} = \frac{{{{{R}}^{{\bf{ - 1}}}}{{a}}}}{{{{{a}}^{{H}}}{{{R}}^{{\bf{ - 1}}}}{{a}}}}{\text{，}}$ (4)

 ${P_{MVDR}} = {{{w}}^{{H}}}{{Rw}} = \frac{1}{{{{{a}}^{{H}}}{{{R}}^{{{ - 1}}}}{{a}}}}{\text{。}}$ (5)

 图 1 目标方位30°测向结果 Fig. 1 Result of azimuth estimation for target at 30°

 图 2 目标方位60°测向结果 Fig. 2 Result of azimuth estimation for target at 60°
2 海上试验 2.1 试验基本情况

2018年3月，在海南万宁附近海域开展了“海底光纤水听器阵高精度测向技术研究”海上验证试验。试验基本情况如下：

 图 3 光纤水听器阵测量示意图 Fig. 3 Situational of fiber optic hydrophone array
2.2 阵元位置标校

 图 4 阵元位置标校结果 Fig. 4 Calibration result of array

2.3 试验结果分析

 图 5 阵列波束形成LOFAR谱 Fig. 5 LOFAR of array beamforming

 图 6 S1点方位时间历程 Fig. 6 Target azimuth time history of S1

 图 7 S2点方位时间历程 Fig. 7 Target azimuth time history of S2

 图 8 S3点方位时间历程 Fig. 8 Target azimuth time history of S3

 图 9 S4点方位时间历程 Fig. 9 Target azimuth time history of S4

3 结　语

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