Design And Implementation Of Hardware Based On Compression Sampling Algorithm For Radio Astronomy Signal

Astronomical research mainly uses astronomical observation techniques to investigate the radio bursts of the sun and planets through full-wave observations.The radio burst information of celestial bodies can be observed in the frequency range below 80 MHz,and the VHF astronomical signal reflects the electromagnetic radiation content of celestial bodies.In order to study the astronomical matter of celestial bodies,it is necessary to use an ultra-high-speed analog-to-digital converter to collect the astronomical signals,but it is difficult to meet the needs of sampling frequency of general analog-to-digital converters.This is a challenge for high-frequency observation of astronomical signals.In this paper,a compressed sampling system based on the theory of modulated broadband converter is designed.The sparse radio astronomy signal is compressed and sampled at an ultra-low sampling rate,and the original signal is reconstructed on the PC side.It is of great significance in engineering applications.First of all,according to the research status of compressed sensing theory,this dissertation selects the principle of modulation wideband converter.After research,it is found that the modulation wideband converter can achieve its function through circuit design hardware,and there are many types of reconstruction algorithms for it.After deeply researching and analyzing the theory of orthogonal matching pursuit algorithm,an improved algorithm based on orthogonal matching pursuit algorithm is proposed and compared with the simulation of typical orthogonal matching pursuit algorithm.At the same time,algorithm research and experimental analysis are also carried out on other algorithms.Then,under the full research and practical verification of the theory of the modulation wideband converter,a four-channel compression sampling system is designed.The system mainly includes two parts:hardware and software.The hardware part includes a pseudo-random sequence generator and a Frequency converter,amplifier,ADC sampling,FPGA main control,software part is based on C#'s host computer data receiving and MATLAB-based reconstruction algorithm to achieve signal reconstruction.Combining the two parts realizes signal compression sampling and original signal recovery,and displays the reconstructed signal waveform in real time on the PC side.Finally,the key parts of the hardware circuit are tested to ensure that each part of the system can operate normally.After preliminary verification of the commissioning experiment,the performance was directly verified in the fieldwork practice of the Yunnan Observatory,and the low-frequency radio antenna array signal was integrated into the system designed for verification.By comparison with the observatory system,the sampling system designed in this paper reconstructs signals.The mean square error of the signal collected by the Observatory is 1.27×10^-2.The storage space compression rate reaches 20%,which directly proves that the compressed sampling system designed in this paper has strong practicality.