HF radar waveform design

HF over-the-horizon radars often use CW transmissions comprising repeated linear FM sweeps. The resolution and sidelobe performance in the range dimension are determined within each sweep, but Doppler information is extracted by processing together the outputs of a number of sweeps. In the paper the authors consider the prospective performance of more complex modulation schemes, including Doppler sensitive waveforms. The performance of nonlinear FM sweeps and quasi-random phase codes are compared. The limitations of these techniques are explored