Dense Spectrum Correcting Methods For Radio Astronomical Signals

Electromagnetic signals radiated from celestial bodies can reflect the characteristics of these objects,it is an important means of study planets.Radio astronomy signal sampling frequency is very high,and some even up to GHz frequency bands.Usually,the sampling frequency is too high and FFT analysis points can't be too high,these leads to the very low frequency resolution.Zoom method based on complex analytic band-pass filter in the case of FFT analysis points not added,can help to reduce the sampling frequency,increase the frequency resolution,is important in signal processing for radio astronomy.Four spectrum correcting method introduced in this paper such as ratio method,the energy center of gravity correction,FFT+FT spectrum zoom and correction based on phase difference and compares the advantages and disadvantages of the four methods,and do the simulation experiments for dense spectrum of these methods do not apply.Ratio method is simple and correction better,faster;FFT+FT spectrum zoom don't increase the length of sample,but speed slower;Phase difference correction method good commonality,the calibration precision is high.But the four methods for single frequency signal or interval distant frequency components.So this paper is based on complex analytic band-pass filter refinement method and ratio combination method for correction,it has advantages of complex frequency adjustment and have high precision,it also can improve the resolution of signal frequencies for radio astronomy signal.The principle,algorithm and implementing process are introduced in detail,simulation is carried out.The frequency resolution is 195312.5Hz before correction,the frequency resolution is 1953.125Hz after correction,so the frequency resolution improved 100 times.The radio astronomical signal simulation results show that complex analytic band-pass filter and ratio based method can increase the frequency resolution of radio astronomical signal with higher accuracy.