Reducing the grating lobes and main lobe width for increasing range resolution using phase and frequency modulated codes

In Radar the good range resolution can be achieved by a short pulse. Short pulse systems are limited resolution because they are narrow band. Using pulse compression technique high range resolution can be achieved in radar system. The barker codes are known as bi-phase codes with minimum side lobes used in phase modulation in pulse compression technique. LFM and NLFM codes are used as frequency modulation. In this paper the wide band signals that is LFM and NLFM codes are modulates Barker codes to get good resolution while getting minimum side lobes and reduction in main lobe width. By introducing LFM in Barker codes grating lobes will be appeared in Autocorrelation function of LFM Barker sequence. To reduce the grating lobes and the main lobe width to get high delay and Doppler resolution, NLFM code is introduced in Barker codes and observed merit factor, side lobe levels, main lobe width and Doppler tolerance from Autocorrelation function as well as ambiguity function.