| In this work we discuss two problems that appear in modern radar waveform design. First, we propose a new approach to one of the most challenging problems in this area of research - the construction of waveforms with optimal ambiguity characteristics in a chosen a priori region surrounding the main lobe. Our approach is based on the projection of the signal onto an appropriate orthonormal basis in the space of radar waveforms and approximating the signal with desired ambiguity properties by a finite number of basis waveforms. In particular, we consider well-known Hermite waveforms as the basis functions and discuss the problem of minimizing the volume under the ambiguity surface over a certain given region.;The second part of the dissertation is devoted to the problem of the range side- lobe suppression in stepped-frequency LFM pulse trains. Frequency stepping is one of the known techniques employed by modern radars to achieve high range resolution. The main advantage of this approach is that the instantaneous bandwidth of a radar is quite small compared with the total processing bandwidth. This allows the transmission of waveforms with extremely wide overall bandwidth (and, as a consequence, the attainment of high range resolution) without the usage of the expensive hardware needed to support the wide instantaneous bandwidth. We present a systematic approach for designing pulse trains producing the autocorrelation function whose sidelobes are less than some predetermined level. |
