Analysis of an optimum hybrid radar waveform using frequency hopping and locally optimum signals

The analysis of a new hybrid waveform designed to optimize both range and velocity resolution is described. Two modulation techniques, frequency agility and direct sequence spreading, are chosen to improve range resolution through pulse compression techniques. The frequency order in a frequency agile radar is chosen so there is at most one coincidence in frequency between the transmitted and Doppler shifted return signal. The ambiguity function is used to illustrate and compare single and hybrid modulated waveforms. It is shown that hybrid signals using phase and frequency modulation can be used to increase range and velocity resolution and improve the peak-to-sidelobe ratio in the presence of Doppler shift. It is also possible to realize the thumbtack nature of the ambiguity diagram through optimal combinations of these two modulation techniques.>