A controller for a FMCW radar system configured to: provide for emission by the FMCW radar system of a plurality of consecutive frequency modulated detection signals for detection and ranging, each of the frequency modulated detection signals varying between an initial frequency and a final frequency over a period of time extending from a start time to an end time; wherein at least one of said consecutive frequency modulated detection signals is provided with an offset to one or more of; the start time of the detection signal relative to a predetermined start time schedule; the end time of the detection signal relative to a predetermined end time schedule; the initial frequency of the detection signal relative to a predetermined initial frequency schedule; and the final frequency of the detection signal relative to a predetermined final frequency schedule; the offset based on a random value.