Waveform diversity

Keywords SBR STAP earth rotation range ambiguity crab angle crab magnitude Doppler dispersion range dependency waveform diversity Doppler warping. 

Waveform diversity can be used on the sequence of transmitted radar pulses to realize the above goal by suppressing the range foldover returns. In ordinary practice, a set of identical pulses are transmitted. To suppress returns due to range foldover, for example, individual pulses... 

S. U. Pillai, B. Himed, K. Y. Li, Waveform Diversity for Space Based Radar, Proc. of Waveform Diversity and Design, Edinburgh, Scotland, Nov 8-10, 2004. 

So far, we have assumed FAIMS waveforms to follow the ordained U(t) dependence. The waveforms produced by real electronics always carry unwanted oscillations (electronic noise) of diverse physical origin, including thermal, shot, and inductive coupling of instmmental and environmental RF. Thermal ( white ) noise has uniform power spectrum that allows unbiased gauging of the impact of noise on FAIMS performance. Other noises appear over limited fiequency ranges ( pink noise) or at specific frequencies such as overtones of harmonics comprising Ed(0 or the industrial AC power frequency (60 Hz in USA) and its overtones. The spectra of those noises are sensitive to specific FAIMS hardware and lab environment. The effect of noise ceases above some frequency because ions have not enough time to respond. Based on the relaxation time estimates (3.2.1),... 

We have focused on the waveforms that remove the influence of any number of sequential leading terms of Equation 2.2 on net ion separation. Other asymmetric profiles can exclude other term combinations (e.g., K(0) and the = 2 term), to be detailed in future work by the author. Such waveforms further expand the diversity of potential IMS methods and, by enabling one to effectively nullify both all terms preceding a certain term in Equation 2.2 and one or more immediately following terms, could be useful for precise measurement of a values. 

---