Performance evaluation of hybrid costas codes for increasing range resolution

Range resolution in Radar can be improved by increasing the time bandwidth product beyond the orthogonality in Costas subpulses. In this paper, Hybrid Costas code is proposed to achieve high range resolution. When the time bandwidth product is exceeded their orthogonality, gives the grating lobes around the mainlobe in the autocorrelation function. The subpulse coding is used for mitigating the grating lobes. In that, nulls are placed before the grating lobes. In this work Costas codes are modified by using Phase codes. Indeed Costas subpulses are nested with Phase codes using Kronecker product to achieve grating lobes mitigation as well as better suppression of peak side lobes. The performance evaluation of Hybrid Costas codes are carried out for different time band width products in the near and far main lobe regions.