Abstract :
Linear stepped frequency radar is used in wide-band radar applications, such as airborne synthetic aperture radar (SAR), turntable inverse SAR, and ground penetration radar. The frequency is stepped linearly with a constant frequency change, and range cells are formed by fast Fourier transform processing. The covered bandwidth defines the range resolution, and the length of the frequency step restricts the nonambiguous range interval. A random choice of the transmitted frequencies suppresses the range ambiguity, improves covert detection, and reduces the signal interference between adjacent sensors. As a result of the random modulation, however, a noise component is added to the range/Doppler sidelobes. In this paper, relationships of random step frequency radar are compared with frequency-modulated continuous wave noise radar and the statistical characteristics of the ambiguity function and the sidelobe noise floor are analyzed. Algorithms are investigated, which reduce the sidelobes and the noise-floor contribution from strong dominating reflectors in the scene. Theoretical predictions are compared with Monte Carlo simulations and experimental data
Keywords :
Monte Carlo methods; airborne radar; fast Fourier transforms; geophysical equipment; ground penetrating radar; synthetic aperture radar; Doppler sidelobe; Monte Carlo simulations; fast Fourier transform; ground penetration radar; noise; random modulation; random step frequency radar; synthetic aperture radar; turntable inverse SAR; Airborne radar; Bandwidth; Doppler radar; Fast Fourier transforms; Frequency; Ground penetrating radar; Radar applications; Radar detection; Signal resolution; Synthetic aperture radar; Random frequency modulation; random noise radar; step frequency radar;
