全相位算法在相控阵天线幅相校正测量中的应用

相控阵天线波束的精确指向对各阵元通道幅相一致性提出了很高的要求,在实际的相控阵天线系统中,各阵元通道幅度和相位不可能完全保持一致,需要对阵列通道幅相误差进行实时地监测和校正。阵列单元校正的本质是对通道幅相误差的精确测量或估计,在现有幅相测量方法的基础上,提出一种全相位时移相位差算法。该算法需对存在时移关系的两输入序列分别进行全相位FFT,直接取主谱线的相位值无需校正即可得到输入信号的中间点相位信息,利用两序列主谱线的相位差求解信号的幅度值。由于全相位FFT具有"相位不变性",此方法能够很好地抑制频谱泄漏。仿真结果表明,该方法可有效避免第一类相位差法在不同步采样时误差较大的情形,测量结果明显优于第一类相位差法。

Application of All Phase FFT Algorithm in Amplitude and Phase Measurement for Phase Array Antenna Calibration

The precise beam pointing of Phased Array Antenna needs high consistency of every array channal.In the actual Phased Array Antenna system,the amplitude and phase of every array channel cannot be completely consistent;therefore,it needs real-time monitoring and adjusting array channel amplitude/phase error.Precisely measuring or estimating the channel amplitude and phase is the essence of array calibration.In this paper,a novel time-shift phase difference of all-phase FFT method is proposed,which is based on all the existing methods.In this method,all-phase FFT is implemented respectively on two input sequences in time-shift relation.And the value of all-phase FFT phase-spectrum at main spectral positon can be directly taken as the phase of the center point without any correcting measures;Moreover,the value of phase difference at main spectral position can be utilized to deduce amplitude estimation.Owing to the property of phase invariant,the method can effectively prevent spectral leakages.Simulation results proves the proposed method can effectively reduce the measurement error,comparing with the first phase difference method in case of nonsychronous sampling,and the measured results is excelled the fist phase difference method.