Effects of wideband waveforms on simultaneous scattering matrix measurement of manoeuvring targets

摘要

Both polarimetry and Doppler characteristics can be employed in remote sensing applications. Doppler information provides insight into the dynamic properties of radar targets, and polarimetry is associated with the intrinsic attributes of targets. Determining how to obtain accurate polarisation measurements from Doppler information has been a concern. For high-speed targets, the relativistic effect on radar wideband echoes may be notable. With the conventional matched filter, this scale effect may produce significant amplitude and phase errors between two columns of the polarisation scattering matrix (PSM), except for signal-to-noise ratio (SNR) loss. On the basis of the Taylor series expansion, the amplitude and phase expressions are derived in this study. Theoretical analysis shows that the amplitude and phase errors are related to the time-frequency allocation of the orthogonal waveforms and that the accuracy of the PSM is more susceptible to scale factors using frequency modulation waveforms than phase-coded waveforms. To suppress these amplitude and phase errors, a compensation method is proposed for orthogonal linear frequency modulation signals. Furthermore, the performances of the SNR loss and the velocity error effect are given. Finally, some numerical experimental results are provided to illustrate the effectiveness of the compensation.