Design Of Radar Array Based On Ambiguity Function

In radar system design and implementation, waveform design and selection is an important issue, because it directly affects the radar system parameters and signal processing algorithms, such as signal processing complexity, transmitter type, effective detection range, interference and anti-interception performance, etc. Since radar ambiguity function is an effective tool for evaluating the performance of various radar waveforms, this paper studied optimal waveform and array design via radar ambiguity function optimization for multiple-input multiple-output(MIMO) and frequency diverse array(FDA) radars. The main contributions of this thesis can be summarized as follows:(1) Derived the MIMO radar ambiguity function and analyzed its basic properties.This thesis derived the MIMO radar signal model under the assumptation of orthogonal transmit waveforms, and then deduced the MIMO radar ambiguity function including auto-ambiguity function and cross ambiguity function. Next, the properties of the MIMO radar ambiguity function are discussed and simulated, which laid the foundation for subsequent optimal MIMO radar waveform and array design.(2) Proposed a modified method to optimize MIMO radar waveform and its array design by exploiting the radar ambiguity function.In order to optimally design MIMO radar waveform, this thesis derived the MIMO radar ambiguity function for pulsed transmit waveforms and established a cost function by maximizing the peak-sidelobe ratio of the ambiguity function. The waveform and array optimization problem is resolved with the improved simulated annealing algorithm. In doing so, this thesis optimally designed the frequency hopping code waveform and linear frequency modulation frequency-hopping codes waveform for MIMO radar, respectively.(3) Derived the FDA radar ambiguity function and analyzed its properties.By exploiting the differences between phased-array and FDA, this thesis derived not only the FDA radar ambiguity function including auto-ambiguity function of the transmitted signals, but also the radar ambiguity function of the receive signal. The basic characteristics and properties of these ambiguity functions are comparatively investigated through theoretical analysis and numerical simulation, which provides a foundation for optimal FDA design presented in subsequent chapter.(4) Proposed a method to optimally design the FDA frequency increment by exploiting the radar ambiguity function.With respect to phased-array, FDA has a small frequency increment applied across the elements, so it is necessary to optimally design this frequency increment. According to the characteristics of the FDA radar ambiguity function, a cost function is established by maximizing the peak-to-sidelobe ratio of the FDA radar ambiguity function to optimize the frequency increment. Since it is a non-convex problem and difficult to be resolved directly, in this thesis it is solved by an improved simulated annealing algorithm.