A controller for a Frequency Modulated Continuous Wave, FMCW, radar system configured to: provide for emission by the FMCW radar system of a plurality of consecutive frequency modulated detection signals (105, 201, 202, 203) 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 of the frequency modulated detection signal to an end time of the frequency modulated detection signal; wherein at least one of said consecutive frequency modulated detection signals is provided with an offset to the initial frequency of the frequency modulated detection signal relative to a predetermined initial frequency schedule; and the final frequency of the frequency modulated detection signal relative to a predetermined final frequency schedule; the offset based on a random value, wherein the controller provides for detection of a reflected detection and ranging signal according to a predetermined detection schedule, wherein the predetermined detection schedule is independent of any offset applied to the one or more of the start time, the end time, the initial frequency or the final frequency and wherein the frequency difference between the initial frequency and the final frequency comprises a fixed predetermined frequency difference, wherein the fixed predetermined frequency difference is the same for each consecutive frequency modulated detection signal and, correspondingly, any offset applied to one of the initial frequency and the final frequency is equally applied to the other of the final frequency and the initial frequency. provide for emission by the FMCW radar system of a plurality of consecutive frequency modulated detection signals (105, 201, 202, 203) 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 of the frequency modulated detection signal to an end time of the frequency modulated detection signal; wherein at least one of said consecutive frequency modulated detection signals is provided with an offset to the initial frequency of the frequency modulated detection signal relative to a predetermined initial frequency schedule; and the final frequency of the frequency modulated detection signal relative to a predetermined final frequency schedule; the offset based on a random value, wherein the controller provides for detection of a reflected detection and ranging signal according to a predetermined detection schedule, wherein the predetermined detection schedule is independent of any offset applied to the one or more of the start time, the end time, the initial frequency or the final frequency and wherein the frequency difference between the initial frequency and the final frequency comprises a fixed predetermined frequency difference, wherein the fixed predetermined frequency difference is the same for each consecutive frequency modulated detection signal and, correspondingly, any offset applied to one of the initial frequency and the final frequency is equally applied to the other of the final frequency and the initial frequency.