Signal processing device of automobile track changing assisting system based on combined waveform

A signal processing device of an automobile track changing assisting system based on a combined waveform belongs to the field of signal processing and is used for resolving relative distance, relative velocity and direction angle on objects which are behind a driving automobile and are in a millimeter wave radar wave beam coverage area. The signal processing device is technologically characterized by comprising the components of an FFT calculating module which performs FFT calculation on waveform segments and IQ data that are acquired by A/D; a threshold detecting module which performs threshold detection on modulus of complex number after FFT transform of each waveform segment and outputs the position of the point with highest modulus of the complex number that corresponds with threshold exceeding; a Doppler frequency calculation module which performs calculation for obtaining the Doppler frequency of a constant-frequency segment; and an offset frequency calculation module which performs calculation for obta