The present invention relates to an object detection system and method for determining range and velocity of a target object by transmitting a frequency modulated continuous wave transmission signal and receiving transmission signal reflections of the transmission signal from the target object as a reception signal. Each modulation block of the transmission signal comprises a number of first type chirps, each first type chirp having a first slope, and a number of second type chirps, each second type chirp having a second slope different from the first slope. Two consecutive chirps of the same type have a frequency offset A mixed signal based on the transmission signal and the reception signal and using the first type chirps and the second type chirps is processed, in order to determine the range and velocity of the target object.