Design and implementation of dual-channel weak signal acquisition system based on Kalman fusion

Aiming at the problems that the equipment is difficult to effectively collect underwater magnetic anomaly signal detection, the dynamic range of analog-to-digital converter is limited, resulting in low signal-to-noise ratio, and weak signals are easily submerged by noise. This thesis designs a high-precision magnetic anomaly signal acquisition system based on domestic field-programmable gate array (FPGA). In order to improve the signal-to-noise ratio and dynamic range of the signal, this paper uses the high-precision multi-channel analog-to-digital conversion chip ADS1278 and the Unisplendour Logos series FPGA to collect the weak magnetic anomaly signal output by the three-axis fluxgate after using 2 times and 8 times gain pre-processing respectively, and then uses the Kalman filter to perform secondary correction on the fused data after the average weighted average of the collected signals for preliminary data fusion. The experimental results show that the accuracy of the fused signal is significantly better than that of the single-channel acquisition signal. When using dual-channel AD to acquire weak signals with a frequency of 200 Hz and an amplitude of 500 μV, the signal-to-noise ratio is improved by 26.099 dB, effectively improving the dynamic range of the data acquisition system.