﻿ 一种应用于航空声呐浮标的磁罗盘设计
 舰船科学技术  2021, Vol. 43 Issue (11): 160-163    DOI: 10.3404/j.issn.1672-7649.2021.11.030 PDF

Design of magnetic compass applied to aerial sonobuoy
ZHANG Yan-yan
The 715 Research Institute of CSSC, Hangzhou 310023, China
Abstract: This paper briefly analyzes the working principle and mathematical model of fluxgate sensor,and designs a magnetic compass based on fluxgate sensor,which has low power consumption,small size,light weight,high reliability and small error, and can achieve batch production by engineering, according to the actual application requirements of aviation sonobuoy.The magnetic compass works stably and reliably through engineering practice,and the root mean square error of azimuth measurement is less than 1 degree,which provides a strong guarantee for the detection performance of sononbuoy.
Key words: sonobuoy     magnetic compass     fluxgate sensor
0 引　言

1 磁通门传感器工作原理

 图 1 磁通门传感器工作原理示意图 Fig. 1 Schematic diagram of the working principle of fluxgate sensor
2 磁通门传感器数学模型

 $e = - {10^{ - 8}}\frac{{\rm{d}}}{{{\rm{d}}t}}(W\mu HS)\text{。}$ (1)

 $H = {H_m}\cos (2\text{π} {f_1}t) \text{，}$ (2)

 $e = 2\text{π} \times {10^{ - 8}}{f_1}\mu WS{H_m}\sin(2\text{π} {f_1}t)\text{。}$ (3)

 $\begin{split} e = &2\text{π} \times {10^{ - 8}}{f_1}\mu (t)WS{H_m}\sin(2\text{π} {f_1}t) -\\ &{10^{ - 8}}\frac{{{\rm{d}}\mu (t)}}{{{\rm{d}}t}}WSH\cos(2\text{π} {f_1}t) \text{。} \end{split}$ (4)

 $\begin{split} \mu (t) =& {\mu _{0m}} + {\mu _{2m}}\cos(4\text{π} {f_1}t) + {\mu _{4m}}\cos(8\text{π} {f_1}t) +\\ &{\mu _{6m}}\cos(12\text{π} {f_1}t) + \cdots \text{。} \end{split}$ (5)

 $\begin{split} e =& 2\text{π} \times {10^{ - 8}}{f_1}\mu (t)WS{H_m}\sin(2\text{π} {f_1}t) -\\ &{10^{ - 8}}\frac{{{\rm{d}}\mu (t)}}{{{\rm{d}}t}}WSH\cos(2\text{π} {f_1}t) - {10^{ - 8}}\frac{{{\rm{d}}\mu (t)}}{{{\rm{d}}t}}WS{H_0} \text{，} \end{split}$ (6)

 $\begin{split} e({H_0}) = & - 2\text{π} \times {10^{ - 8}}{f_1}WS{H_0}(2{\mu _{2m}}\sin(4\text{π} {f_1}t) + \\ & 4{\mu _{4m}}\sin(8\text{π} {f_1}t) + 6{\mu _{6m}}\sin(12\text{π} {f_1}t) + \cdots )\text{。} \end{split}$ (7)

3 方案设计

 图 2 磁罗盘组成框图 Fig. 2 Block diagram of magnetic compass

3.1 功率放大电路

 $\text{N'S'感应信号}\;{H'_0}\cos (\alpha )\sin (4\text{π} {f_1}t)\text{，}$ (8)
 $\text{ E'W'感应信号} \;{H'_0}\sin (\alpha )\sin (4\text{π} {f_1}t) \text{。}$ (9)

 图 3 激励信号与感应信号对比图 Fig. 3 Comparison of excitation signal and induction signal
3.2 调理电路

1）带通滤波电路

 图 4 带通滤波器幅频特性 Fig. 4 Amplitudefrequency characteristics of a bandpass filter

 图 5 带通滤波器相频特性 Fig. 5 Phasefrequency characteristics of a bandpass filter

2）检波电路

 $\text{N'S'感应信号}\;{V_x} = {H''_0}\cos (\alpha )\text{，}$ (10)
 $\text{E'W'感应信号}\;{V_y} = {H''_0}\sin (\alpha ) \text{。}$ (11)
3.3 数据采集、处理电路

FPGA控制AD采集磁罗盘两路感应输出信号 ${V_x}$ ${V_y}$ ，利用PFGA内部处理器进行数字信号处理，计算磁方位角。磁方位角的计算对两路感应信号的电压值 ${V_x}$ ${V_y}$ 比较敏感，当 ${V_x}$ ${V_y}$ 出现波动、毛刺时，会引起磁方位角的波动，因此一般工程应用上在进行方位计算前要对两路感应信号进一步处理，如图6所示。

 图 6 数字信号处理流程图 Fig. 6 Digital signal processing flowchart

 ${G_L} \leqslant {({V_x})^2} + {({V_y})^2} \leqslant {G_H} \text{，}$ (12)

 $\left| \alpha \right| = \arctan ({{{V_y}}/{{V_x}}})\text{，}$ (13)

 $\left\{\begin{array}{*{20}{l}} \alpha = \arctan ({{{V_y}} /{{V_x}}})&{V}_{x} > 0\text{，}{V}_{y}\geqslant 0\text{，}\\ \alpha = 90 & {V}_{x}=0\text{，}{V}_{y} > 0\text{，}\\ \alpha = \arctan ({{{V_y}} / {{V_x}}}) + 180 & {V_x} < 0\text{，}\\ \alpha = 270 &{V}_{x}=0\text{，}{V}_{y} < 0\text{，} \\ \alpha = \arctan ({{{V_y}}/ {{V_x}}}) + 360 & {V}_{x} > 0\text{，}{V}_{y} < 0\text{。} \end{array}\right.$ (14)
4 测试结果

 图 7 磁罗盘测磁方位角误差曲线 Fig. 7 Magnetic azimuth error curve of magnetic compass

 $\Delta \alpha = \sqrt {{{({{(\Delta {\alpha _1}{\text{ - }}\bar \alpha )}^2} + {{(\Delta {\alpha _2}{\text{ - }}\bar \alpha )}^2} \cdots + {{(\Delta {\alpha _n}{\text{ - }}\bar \alpha )}^2})} \mathord{\left/ {\vphantom {{({{(\Delta {\alpha _1}{\text{ - }}\bar \alpha )}^2} + {{(\Delta {\alpha _2}{\text{ - }}\bar \alpha )}^2} \cdots + {{(\Delta {\alpha _n}{\text{ - }}\bar \alpha )}^2})} n}} \right. } n}}\text{。}$ (15)

5 结　语

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