Abstract:

The form of wide-band group delay is analyzed and Ka-band interferometry is taken as the background. For the problem of nonlinear distortion of channel group delay, a calibration method based on cross-correlation of phase calibration (PCAL) signals is proposed. Comb-spectrum and linear phase are key characteristics of PCAL, according to this, the phase-frequency characteristic curve of crosscorrelation is obtained by extracting PCAL’s phase, and then the channel group delay is calculated. For parabolic group delay, third-order nonlinear fitting is used to replace the traditional first-order linear fitting. Simulation results show that when the signal-to-noise ratio is -10 dB, the third-order fitting has a higher agreement with the original phase-frequency characteristic curve, the standard deviation accounts for 1/4 of the first-order fitting and the group delay result is closer to the true value. The validity of the algorithm is proved.