Lanterna Rally

Author: Yanbo Xue

Publisher:

Published: 2010

Total Pages: 370

ISBN-13:

For over six decades, the theory and design of radar systems have been dominated by probability theory and statistics, information theory, signal processing and control. However, the similar encoding-decoding property that exists between the visual brain and radar has been sadly overlooked in all radar systems. This thesis lays down the foundation of a new generation of radar systems, namely cognitive radar, that was described in a 2006 seminal paper by Haykin. Four essential elements of cognitive radar are Bayesian filtering in the receiver, dynamic programming in the transmitter, memory, and global feedback to facilitate computational intelligence. All these elements excluding the memory compose a well known property of mammalian cortex, the perception-action cycle. As such, the cognitive radar that has only this cycle is named as the basic cognitive radar (BCR). For tracking applications, this thesis presents the underlying theory of BCR, with emphasis being placed on the cubature Kalman filter to approximate the Bayesian filter in the receiver, dynamic optimization for transmit-waveform selection in the transmitter, and global feedback embodying the transmitter, the radar environment, and the receiver all under one overall feedback loop. Built on the knowledge learnt from the BCR, this thesis expands the basic perception-action cycle to encompass three more properties of human cognition, that is, memory, attention, and intelligence. Specifically, the provision for memory includes the three essential elements, i.e., the perceptual memory, executive memory, and coordinating perception-action memory that couples the first two memories. Provision of the three memories adds an advanced version of cognitive radar, namely the nested cognitive radar (NCR) in light of the nesting of three memories in the perception-action cycle. In this thesis, extensive computer simulations are also conducted to demonstrate the ability of this new radar concept over a conventional radar structure. Three important scenarios of tracking applications are considered, they are (a), linear target tracking; (b), falling object tracking; and (c), high-dimensional target tracking with continuous-discrete model. All simulation results confirm that cognitive radar outperforms the conventional radar systems significantly. In conducting the simulations, an interesting phenomenon is also observed, which is named the chattering effect . The underlying physics and mathematical model of this effect are discussed. For the purpose of studying the behaviour of cognitive radar in disturbance, demonstrative experiments are further conducted. Simulation results indicate the superiority of NCR over BCR and the conventional radar in low, moderate and even strong disturbance.