Simulation Research on Precision Digital Fluxgate Magnetometer Based on Sigma-Delta Modulation Technology
-
摘要: 设计了一种基于1 bit Sigma-Delta环路调制技术的高精度数字磁通门磁强计，建立了数字磁强计信号处理仿真模型，并利用Matlab的Simulink仿真工具开展了数字磁通门磁强计模型的仿真分析，对数字磁强计系统的噪声、线性度、响应速度和频率响应进行了仿真计算。利用本文1 bit Sigma-Delta环路调制技术的数字磁强计在量程超过±105 nT的情况下，系统在1 Hz处的噪声仅为4.66 pT·Hz–1/2，最大线性偏差为0.16 nT，动态响应速度达到2×106 nT·s–1，频率响应带宽超过10 Hz。仿真结果表明，基于1 bit Sigma-Delta环路调制技术的数字磁通门磁强计可以有效降低对A/D转换器精度的要求，在保证性能的前提下大幅度降低了电路复杂程度，提高了系统的可靠性，在深空探测、空间磁场测量等领域具有广泛的应用前景。
-
关键词:
- 数字磁通门磁强计 /
- 1 bit ADC /
- Sigma-Delta调制 /
- CIC抽取滤波器 /
- Simulink仿真工具
Abstract: A precision digital fluxgate magnetometer was designed based on Sigma-Delta modulation technology. Signal processing simulation model is carried out with Simulink tools in Matlab, simulation analysis of magnetometer characteristics is given, including the noise, linearity, response speed and frequency characteristic. The simulation results show that the measurement range of 1 bit digital magnetometer could reach more than ±105 nT to cover Earth magnetic field, system noise is lower than 4.66 pT·Hz–1/2 at 1 Hz which means the resolution is sufficient for deep space magnetic field exploration. The maximum nonlinear error is 0.16 nT and the dynamic response speed reaches 2×106 nT·s–1 and the efficient Bandwidth is higher than 10 Hz. The simulation results indicate that 1bit digital fluxgate magnetometer could effectively reduce the critical requirements of the accuracy on the A/D converter, simplify the analog signal processing electrical circuit and improve the system reliability. The performance of 1 bit Sigma-Delta digital magnetometer indicates its impressive advantages over traditional magnetometers and wide application prospects in the field of deep space exploration and space magnetic field measurement.-
Key words:
- Digital fluxgate magnetometer /
- 1 bit ADC /
- Sigma-Delta modulation /
- CIC Decimation filter /
- Simulink
-
图 4 1 bit数字磁通门磁强计仿真系统
Figure 4. Simulation system of 1 bit digital fluxgate magnetometer
图 5 Mash2-1级联Sigma-Delta调制器
Figure 5. Sigma-Delta modulator of Mash2-1 cascaded modulator
图 9 1 bit ADC中CIC滤波器的补偿滤波器与级联滤波器幅频响应。(a)（0，Fs /2）幅频响应，(b) 20 kHz带宽幅频响应
Figure 9. Amplitude-frequency response of CIC filters in 1 bit ADC. (a) Amplitude-frequency response of (0, Fs /2), and (b) response of 20 kHz
图 12 测量磁场的输出线性度(a)以及误差（b）
Figure 12. Measurement of output linearity of magnetic field (a) and linearity error (b)
表 1 空间探测Sigma-Delta数字磁强计的性能参数
Table 1. Performance of Sigma-Delta digital fluxgate magnetometers for space exploration
探测任务 量程/nT 数字分辨率/bit 噪声功率谱密度/(pT·Hz–1/2)@ 1 Hz 非线性偏差 DAWN ±2000 15.8 21 $ 3.3\times {10}^{-5} $ THEMIS ±4000 20 25 $ - $ MMS ±650（小量程） 24 8 $ 3\times {10}^{-5} $ ±10500（大量程） 100 $ 6\times {10}^{-4} $ Arase（ERG） $ \pm 8000 $（小量程） 20 $ 10.5 $ $ 1.4\times {10}^{-3} $ $ \pm 60000 $（大量程） $ 1.8\times {10}^{-4} $ 
下载: 导出CSV
表 2 1 bit数字磁通门磁强计各模块参数
Table 2. Parameters of modules in 1 bit digital fluxgate magnetometer
磁通门模块 参数 设计测量带宽/ Hz 10 设计量程/ nT ±105 激励频率/ kHz 10 1 bitADC采样频率/ MHz 20.48 相敏检波参考频率/ kHz 20 离散积分器采样频率/ MHz 5.12 环路Sigma-Delta采样频率/ MHz 5.12 反馈模拟滤波器通带/ Hz 2500 输出CIC滤波器抽取率 128 输出数据频率/ Hz 40
下载: 导出CSV
表 3 不同参数下环路调制器对系统性能影响的比较
Table 3. Performance comparison of different loop modulator parameters
关键参数 调制器频率/
MHz比较器死区
设置噪声/
($ \mathrm{p}\mathrm{T}\cdot {\mathrm{H}\mathrm{z}}^{-1} $)噪声峰峰值/nT 1 5.12 ±1/104 4.7 0.15 2 2.56 ±1/104 51.0 6.45 3 1.28 ±1/104 464.6 23.79
下载: 导出CSV
表 4 系统响应速度的仿真条件
Table 4. Simulation conditions for system dynamic response speed
仿真条件 磁场频率/
Hz磁场幅值/
nT前置放大器
增益1 bit ADC
增益系统响应
速度/(nT·s–1)仿真1 2 105 10 1 $ 2\times {10}^{6} $ 仿真2 2 105 10 0.5 $ 1\times {10}^{6} $
下载: 导出CSV
表 5 Sigma-Delta数字磁强计的性能对比
Table 5. Performance comparison of Sigma-Delta digital magnetometers
探测任务 量程/nT 数字分辨率/bit 噪声功率谱密度/(pT·Hz–1/2)@ 1 Hz 非线性偏差 DAWN ±2000 15.8 21 $ 3.3\times {10}^{-5} $ THEMIS ±4000 20 25 $ - $ MMS ±650（小量程） 24 8 $ 3\times {10}^{-5} $ ±10500（大量程） 100 $ 6\times {10}^{-4} $ Arase（ERG） $ \pm 8000 $（小量程） 20 $ 10.5 $ $ 1.4\times {10}^{-3} $ $ \pm 60000$（大量程） $ 1.8\times {10}^{-4} $ 1 bit DFM ±100000 24 4.7 $ 8\times {10}^{-7} $
下载: 导出CSV
-
[1] 李磊, 王劲东, 周斌, 等. 磁通门磁强计在深空探测中的应用[J]. 深空探测学报, 2017, 4(6): 529-534LI Lei, WANG Jindong, ZHOU Bin, et al. Application of fluxgate magnetometer in deep space exploration[J]. Journal of Deep Space Exploration, 2017, 4(6): 529-534 [2] BELYAYEV S, IVCHENKO N. Digital fluxgate magnetometer: design notes[J]. Measurement Science and Technology, 2015, 26(12): 125901 doi: 10.1088/0957-0233/26/12/125901 [3] MAGNES W, PIERCE D, VALAVANOGLOU A, et al. A sigma-delta fluxgate magnetometer for space applications[J]. Measurement Science and Technology, 2003, 14(7): 1003-1012 doi: 10.1088/0957-0233/14/7/314 [4] RUSSELL C T, CHI P J, DEARBORN D J, et al. THEMIS ground-based magnetometers[J]. Space Science Reviews, 2008, 141(1/2/3/4): 389-412 [5] RUSSELL C T, ANDERSON B J, BAUMJOHANN W, et al. The magnetospheric multiscale magnetometers[J]. Space Science Reviews, 2016, 199(1/2/3/4): 189-256 doi: 10.1007/s11214-014-0057-3 [6] MATSUOKA A, TERAMOTO M, NOMURA R, et al. The ARASE (ERG) magnetic field investigation[J]. Earth, Planets and Space, 2018, 70: 43 doi: 10.1186/s40623-018-0800-1 [7] 丁俊鹏. 宇航用三轴磁通门磁强计研制[D]. 哈尔滨: 哈尔滨工业大学, 2017DING Junpeng. Development of Three Axis Fluxgate Magnetometer for Space Application[D]. Harbin: Harbin Institute of Technology, 2017 [8] 支萌辉. 高精度数字磁通门传感器研究[D]. 苏州: 苏州大学, 2017ZHI Menghui. Research on High-precision Digital Fluxgate Sensor[D]. Suzhou: Soochow University, 2017 [9] 王劲东, 赵华, 周斌, 等. 火星空间环境磁场探测研究——“萤火1号”磁强计的研制与应用[J]. 物理, 2009, 38(11): 785-792 doi: 10.3321/j.issn:0379-4148.2009.11.003WANG Jindong, ZHAO Hua, ZHOU Bin, et al. Martian space environment magnetic field research: development and application of the YH-1 precision magnetometer[J]. Physics, 2009, 38(11): 785-792 doi: 10.3321/j.issn:0379-4148.2009.11.003 [10] 唐列娟. 磁场反馈式磁通门磁强计研究[D]. 武汉: 华中科技大学, 2006TANG Liejuan. Study of Magnetic Field Feedback Fluxgate Magnetometer[D]. Wuhan: Huazhong University of Science & Technology, 2006 [11] 王劲东, 周斌, 赵华, 等. 萤火一号火星探测器磁通门磁强计研制[J]. 上海航天, 2013, 30(4): 174-178WANG Jindong, ZHOU Bin, ZHAO Hua, et al. Development of fluxgate magnetometer for YH-1 mars probe[J]. Aerospace Shanghai, 2013, 30(4): 174-178 [12] KAWAHITO S, CERMAN A, ARAMAKI K, et al. A weak magnetic field measurement system using micro-fluxgate sensors and delta-sigma interface[J]. IEEE Transactions on Instrumentation and Measurement, 2003, 52(1): 103-110 doi: 10.1109/TIM.2003.809073 [13] CERMAN A, KUNA A, RIPKA P, et al. Digitalization of highly precise fluxgate magnetometers[J]. Sensors and Actuators A:Physical, 2005, 121(2): 421-429 doi: 10.1016/j.sna.2005.03.053 [14] 周伶俐. Sigma-delta调制器的研究及其在SIMULINK环境下建模[D]. 武汉: 华中科技大学, 2007ZHOU Lingli. Research on Sigma-delta Modulator and Modeling in Simulink[D]. Wuhan: Huazhong University of Science and Technology, 2007 [15] 曹桂平. 高精度Sigma-Delta调制器研究及ASIC实现[D]. 合肥: 中国科学技术大学, 2012CAO Guiping. Study and ASIC Implementation of High-Resolution Sigma-Delta Modulator[D]. Hefei: University of Science and Technology of China, 2012 [16] 冯维婷. 多速率采样中的CIC滤波器设计与分析[J]. 现代电子技术, 2007, 30(14): 18-20 doi: 10.3969/j.issn.1004-373X.2007.14.008FENG Weiting. CIC filter design and analysis in multiple sampling[J]. Modern Electronics Technique, 2007, 30(14): 18-20 doi: 10.3969/j.issn.1004-373X.2007.14.008 [17] HOGENAUER E. An economical class of digital filters for decimation and interpolation[J]. IEEE Transactions on Acoustics, Speech, and Signal Processing, 1981, 29(2): 155-162 doi: 10.1109/TASSP.1981.1163535 [18] ALTERA. Understanding CIC Compensation Filters[EB/OL]. Application Note 455, April 2007, ver. 1.0. https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/an/an455.pdf [19] 吴笑峰. 高精度sigma-delta ADC的研究与设计[D]. 西安: 西安电子科技大学, 2009WU Xiaofeng. Study and Design of High-Resolution Sigma-Delta ADC[D]. Xi’an: Xidian University, 2009 -
下载:
点击查看大图
计量
- 文章访问数: 546
- HTML全文浏览量: 267
- PDF下载量: 74
- 被引次数: 0
