Waveform and system design for colocated MIMO radar

Abstract

Upon the completion of this thesis, I would like to thank many people who have offered me invaluable help and guidance throughout the three years of research. First, I would like to express my sincere gratitude to my mentor, Dr. Saman S. Abeysekera, who has guided and advised me in every single stage along the way of my stay at Nanyang Technological university (NTU) as a PhD student. He never fails to inspire me on my research work with his valuable suggestions, advices, and comments through emails, meetings, or tea time talks. For me, he is a great advisor and friend, rather than a supervisor. I have learnt from him not only the research methodology and engineering skills, but also the appropriate attitudes to face the inevitable ups and downs and dilemmas encountered in one's life. I am also very grateful to Dr. Andy, W. H. Khong, who has brought me to graduate research environment when I was pursuing my MSc degree in Signal Processing. He has provided great help on programming using Matlab and technical paper writing. I thank him for his patience and guidance in helping a fresh research student to build up the basic abilities. I also thank him for giving me the opportunity to experience the collaboration with industry R&D departments. I would like to thank the technicians in Center for Signal Processing (CSP) at School of Electrical and Electronic Engineering (EEE) of NTU, Mr. YANG Yong Seng and Ms. TEO Siok khim. They are so friendly, polite, and considerate, who are always ready to support me with lab facilities and guidance. Last but not least, I would express my special thanks to my parents, HUA Shi Jian, HE Yu Mei, and my wife, LIU Ying. It is their continual love and support that enable me to conquer the challenges in my life and complete this work.

Robust transmit beampattern design for uniform linear arrays using correlated LFM waveforms

“…We note that the finite-word-Iength effects are inherent in practical implementations of digital fil ters [lO]. As such we will use the finite word-length effects as an optimality criterion in the proposed robust design [11]. Let the word rounding step-size of the wavefonns and the multi plier output be Ql and Q 2 respectively.…”

“…However if fa is chosen too small such that the LFM waveforms are highly correlated (as can be seen from Fig. 1), then large values will appear in the diagonal elements of A -I , which results in a large value of 11""112 in (11) and amplifies the quantization error. Hence, with the incorporation of (12), the overall optimization prob lem for robust transmit beampattern design using LFM wave forms is formulated as min IRk, k+Llk (fo) 1 + I fo l U,jo…”

“…The bandwidth and time duration of the LFM waveforms are set as B = 100 kHz, and T = 1 ms. Because (4)- (7) indicate that the transmit beampattern is independent of V, we set V = Vo = I. Note that V only affects IIWl12 as indicated in (11). It is seen from Fig.…”

“…However, reducing fa increases the correlations of the LFM waveforms, which results in large values appearing in A -1 and thus IIWII2 becomes very sensitive to V due to (11). In this situation, V need to be carefully selected to limit…”