Liu Zhi-wen

Uni-vector-sensor SOS/HOS-CSS for wide-band non-Gaussian source direction finding

The uni-vector-sensor and second-order statistics (SOS)/higher-order statistics (HOS) based coherent signal subspace (UVS-SOS/HOS-CSS) technique is herein proposed for 2-D direction finding of multiple wide-band partially/completely correlated sources with non-vanished Kurtosis. Both the UVS-SOS-CSS and the UVS-HOS-CSS inherit the original coherent signal subspace (CSS) technique in coherently accumulating a group of quadrcovariance matrices associated with different frequency bins, but differs from it in eliminating the focusing operation due to the frequency-independence feature enjoyed by ONE VSs manifold vector. This UVS-SOS/HOS-CSS also excels the spatial smoothing (SS) technique in saving aperture, being blind to Gaussian noise of unknown SOS for coherent sources, and applicability to general array geometry. Representative examples demonstrating this present UVS-SOS/HOS-CSSs behavior are also given.

Design and implementation of an FPGA-based real time simulation system for photovoltaic power generation

The real-time simulation of photovoltaic systems requires microsecond level simulation step size and its hard to implement. In this paper, a real-time simulation system based on FPGA was designed and implemented which can realize the real-time simulation of photovoltaic power systems and the simulation step reached 1μs. System design and implementation method was introduced in detail, including the design of realtime simulation IP core. The whole process from system model to real-time simulation was discussed. And the function of the system was verified by conducting modeling and simulation of photovoltaic power system.

A new method for simultaneous estimation of Doppler frequency and DOA

A new method is proposed to provide the simultaneous estimation of both the Doppler frequency and the direction-of-arrival (DOA) of multiple signals received by a pulse Doppler phased array radar. Based on the concept of multiple invariance, this approach automatically pairs the Doppler frequencies and DOAs by computing them directly from the eigenvalue decomposition of a so-called signal space-time matrix (SSTM). Simulation results show that the proposed method is effective.

Study on radar range profiles for target recognition

In the high frequency region, the radar range profiles are chosen as feature detectors for target recognition. The profile is dependent on the aspect of the target. In order to make radar target recognition (RTR) more effective, the definitions of correlation length and correlation angle are given. In the frequency domain, the most important feature of the shape of a profile is mainly contained in its spectral phase not in its spectral magnitude. So the spectral phase holds important feature information for RTR in the high frequency region, and should be utilized effectively.

A two-step adaptive beamforming approach

A two-step adaptive beamforming approach is introduced, which forms the desired radiation pattern through linear combination of a family of auxiliary beams after the number and locations of spatial emitters are obtained by spectral estimation. This algorithm has excellent performance in jamming cancellation, stability, and computational complexity.