基于伪随机系统辨识的电磁法仪器标定

Instrument calibration with electromagnetic method based on pseudorandom system identification

针对电磁法仪器标定需求,提出基于伪随机互相关辨识的标定方法。论述逆重复m伪随机编码序列的产生方法,从自相关函数出发,推导逆重复m序列的频谱解析式。分析互相关法系统辨识进行仪器标定的原理,给出以逆重复m序列为标定信号源时仪器和磁场传感器的标定方程,并讨论逆重复m序列的参数选取原则。最后,采用相关辨识分别对测量通道和感应式磁场传感器进行标定测试。实测结果表明,标定结果幅度误差小于0.2%,相位误差小于0.5°;标定频率分辨率为0.244 Hz,与传统的方波标定相比效率提高了75倍。该标定方法准确快速,频率分辨率高,可广泛应用于电子仪器标定。

Aiming at the demand of electromagnetic instrument calibration,a calibration method based on cross correlated identification using pseudorandom signal is proposed.The generation method of invert-repeated pseudo-random encoding m-sequence is discussed.The spectral analytic expression of the invert-repeated m-sequence is deduced starting from the self-correlation function.The principle of in-strument calibration based on cross correlated identification is analyzed;the calibration equations of the instrument and the magnetic field sensor are given when the invert-repeated m-sequence is used as the calibration signal source.The parameter selection principle of the invert-repeated m-sequence is discussed.Finally,calibration tests of the instrument and the magnetic field sensor were conducted re-spectively based on correlated identification.The calibration results show that the amplitude error is less than 0.2%,the phase error is less than 0.5 ＆#176;and the calibration frequency resolution is 0.244 Hz;compared with traditional square wave calibration method,the cali-bration efficiency is improved by 75 times.The proposed calibration method is accurate,fast,has high frequency resolution and can be widely used in electronic instrument calibration.