Suppressing coherent noise in radar applications with long dwell times

A method for suppressing internally produced coherent noise in radar applications is presented and experimentally demonstrated. The technique enhances conventional coherent averaging and involves interpulse phase modulation that is introduced digitally in the transmit waveform and removed digitally following digitization in the receiver. Experimental demonstration of this concept resulted in an additional noise floor reduction of 15 to 20 dB (compared to the conventional coherent averaging alone) when the number of coherent averages was between 1000 to 100 000, beyond which no significant suppression was observed.