A frequency measurement method based on optimal multi-average for increasing proton magnetometer measurement precision

作者：Tan, Chao^*; Wang, Jiacheng; Li, Zongliao

来源：Measurement, 2019, 135: 418-423.

DOI：10.1016/j.measurement.2018.10.016

• Frequency estimation
• Optimal multi-average
• PM
• Weak magnetic field measurement

The measurement precision of proton magnetometers (PM) depends on the measurement accuracy of low signal-to-noise ratio (SNR) Larmor frequency which output from sensors. In order to obtain high precision, an optimal multi-average frequency measurement (OMAM) algorithm is proposed. By analyzing the influence of noise in low SNR Larmor frequency signal on the accuracy of frequency measurement, a multi-average frequency measurement method is introduced, and a mathematical model of multiaverage frequency measurement method relative error is established. Based on this model, the optimal value of average times is induced under the case that the frequency measurement cycle number is constant. The frequency measurement contrast experiment result shows that, compared with the multi-cycle synchronous frequency measurement (MCSM) method and the delay multi-channel parallel measurement (MCPM) method, the frequency measurement accuracy for low SNR sine signal is significantly increased by proposed method. The field experimental result shows that the noise power spectral density (NPSD) of PM prototype is about 0.2 nT/Hz1/2 from 0.3 Hz to 1 Hz when proposed method is adopted.

• 出版日期2019-3
• 单位三峡大学