分布式电磁接收系统多频标定信号的产生与检测

为了提高分布式电磁接收系统频域标定的效率和精度,提出了一种基于多频伪随机信号的标定方法并研究了多频标定信号的产生和标定数据的处理方法。首先,根据多频伪随机信号的解析式分析了其主频点的振幅和分布特点,通过现场可编程门阵列(FPGA)实现了伪随机信号的编码合成并产生了高精度双极性标定信号源。然后,基于相关检测的噪声抑制原理,给出了检测含噪声多频标定输出信号幅度和相位的多次相关迭代法并通过仿真进行了验证。最后,对分布式双通道电磁接收系统的采集通道和磁场传感器进行了标定测试。结果表明:在外界噪声不大于标定输出信号幅度的环境下,检测结果幅度误差小于2%,相位误差小于1°。该标定方法快速准确,可用于分布式电磁接收系统在不同野外环境下的频域标定。

Generation and detection of multi-frequency calibration signal for distributed electromagnetic receiver

To improve the efficiency and accuracy of calibration in frequency domain for a distributed electromagnetic receiver, a calibration method based on multi-frequency pseudo-random signal was proposed and the generation and detection of the signals were investigated. According to the analytical expression of multi-frequency pseudo-random signals, the amplitude and distribution characteristics of the main frequency were analyzed,and a high-precision bipolar calibration source was produced through a Field Programming Gate Array(FPGA) to achieve the encoding synthesis of pseudo-random signals. Based on the noise suppression principle of correlation detection, an iterative method with multiple times for the amplitude and phase of a noisy multi-frequency calibration output signal was given,then it was validated by a simulation. Finally, the acquisition channels of the distributed dual-channel electromagnetic receiving system and a magnetic field sensor were calibrated actually. The results indicate that the amplitude error and the phase error are less than 2% and 1°,respectively, while the outside noise is not greater than the calibration output signal. The calibration method is fast, accurate and can be used in the frequency-domain calibration of distributed electromagnetic receiving systems in various field environments.