“…Grating lobes are caused by maxima of R 2 (τ ) that appear at τ (k) = k tp∆f t p where k = 0, ±1, ±2 • • • ± floor(t p ∆f ). In the case of rectangular pulses, R 1 ( τ tp ) has a triangular shape and R( τ tp ) shows equally spaced, linearly decreasing grating lobes, as shown in Fig 3, for the Costas code [2,6,3,8,7,5,1,4] and ∆f = 5 tp . Based on the above considerations, a change in Costas pulse waveforms must be operated in order to shape pulse ACF R 1 ( τ tp ) in such a way that, when combined with R 2 ( τ tp ), grating lobes are lowered.…”