Research Of Signal Processing Mechanism For Fully Polarimetric Radar

Exploiting polarimetric information can greatly enhance radar capabilities, such as target detection and recognition, so it is a trend to study polarization technology and develop polarimetric radar. In this thesis, we focus on the radar target scattering matrix measurement, which is the foundation of exploiting polarimetric information. The measurement technique for full polarimetric radar is studied by the approach of theory analysis and engineering practice, and the full polarization measurement method is analysed by synthetic and real data. The investigations include:1. It is a robust approach to estimate radar target scattering matrix by instantaneous polarization measurement. Although the approach makes the polarization scattering matrix available on a pulse-by-pulse basis, it will be masked by two types of interference arising from the non-idea properties of signal auto-correlation and cross-correlation function. The one type of interference is from an interfering target due to the sidelobes of auto-correlation function, the other one is from the same target or an interfering target due to nonzero values of cross-correlation.In this thesis, the adaptive MMSE (Minimum mean-square error, MMSE) filtering concept is generalized for adaptive pulse compression of instantaneous polarimetric radar. The approach jointly separate and pulse compress the concurrently received return signals from other polarimetric channels, and eliminate of range sidelobes due to the auto-correlation function and the interference of other channels. The proposed method is compared with the standard matched filter and is shown to be superior over a variety of stressing scenarios. Additionally, the arithmetic can be also applied for the pulse compression of the time-divided polarization measurement.2. The method, making good use of Golay complementary codes and Alamouti space-time codes, can eliminate the conflict between autocorrelation and crosscorrelation of waveforms for full radar polarimetry. According to the polarimetric measurement method, a simple signal processing mechanism with doppler compensation for the receiver is considered and analysed in this thesis. The simulation result presents that it can attain good performance when the doppler shift induced by the movement of target is large. Additionally, the architecture is so simple that it is easy to realize.3. The technology of radar polarimetry and the development of polarimetric radar is interactional. With the experience of engineering practice for an instantaneous polarimetric radar system, the function and structure of the system, and the signal processing architecture of each subsystem is introduced in this thesis. Then, the criteria of waveform design for instantaneous radar polarization measurement is described, and an arbitrary waveform generator is designed for the waveform generation. Finally, the instantaneous polarization measurement method and the waveform design is analysed and validated by the experiment data.