Exploitation of Modulation Properties For Blind Adaptive Signal Processing

研究开发和评估利用随机调制正弦波和脉冲序列信号的特性来完成检测和到达时间差（TDOA）估计、相控阵到达方向（DOA）估计和波束/零导向信号提取以及周期性时变信号校正的算法。正在考虑单平台和多平台接收。所开发的特性包括由循环平稳性和周期或恒定模量特性引起的光谱自相干性。所研究的算法进行盲自适应信号处理，避开了传统自适应处理通常需要的训练信号、导频信号、前导、DOA知识等。正在研究的检测和TDOA算法使用基于fft的自动和交叉谱相关测量来执行信号选择性检测和TDOA估计。相控阵算法利用奇异值分解和循环相关矩阵投影实现信号选择性DOA估计，并通过谱自相干恢复实现波束/零导向信号提取。信号校正算法使用载波模量和基带模量恢复来适应周期性时变（移频）滤波器，以抑制共信道干扰，并校正多径和其他失真。有些算法同时采用自相干恢复和模量恢复。所有正在研究的算法所需的先验信息是至少一个周期平稳频率的知识-通常是感兴趣的信号-例如波特率或载波频率，并且在某些情况下，对感兴趣的信号和干扰信号的这种频率都有了解。正在进行的研究是基于理论分析和计算机模拟。这项研究集中在重大问题上，由一位非常合格的研究人员进行。强烈建议提供支持。

Research is being conducted to develop and evaluate algorithms that exploit the properties of randomly modulated sine-wave and pulse-train signals to accomplish detection and time-difference-of-arrival (TDOA) estimation, phase-array direction-of-arrival (DOA) estimation and beam/null-steering signal extraction, and periodically time-variant signal correction. Both single-platform and multiple-platform reception is being considered. The properties being exploited include the spectral self-coherence that results from cyclostationarity, and periodic or constant modulus properties. The algorithms being studied perform blind adaptive signal processing which circumvents the need for training signals, pilot signals, preambles, knowledge of DOA, and so on, which are typically required for conventional adaptive processing. The detection and TDOA algorithms under investigation use FFT-based measurements of auto- and cross-spectral correlation to perform signal- selective detection and TDOA estimation. The phase-array algorithms use singular-value-decomposition and projection of cyclic correlation matrices to accomplish signal-selective DOA estimation and to accomplish beam/null-steering signal extraction by performing spectral self-coherence restoral. The signal correction algorithms use both carrier-modulus and base-band-modulus restoral to adapt periodically time-variant (frequency-shifting) filters for cochannel interference rejection, and correction of multipath and other distortion. Some algorithms employ both self-coherence restoral and modulus restoral. The a priori information required by all the algorithms being investigated is knowledge of at least one frequency of cyclostationarity - typically for the signal of interest - such as a baud rate or carrier frequency and, in some cases, knowledge of such frequencies for both the signal of interest and interfering signals. The research being conducted is based on both theoretical analysis and computer simulations. This research focusses on significant problems and is being conducted by a well qualified researcher. Support is highly recommended.