Ramp sequence analysis to resolve multi target scenarios for a 77-GHz FMCW radar sensor

Many practical frequency-modulated continuous-wave (FMCW) radars utilize consecutive upchirps and/or downchirps of the same ramp slope to extract the desired range and velocity information of the targets. In this contribution it is demonstrated that consecutive ramp sequences provide only little more information compared to a non-consecutive sequence, but lead to a huge calculation complexity. Additional significant information on the target states for a non-consecutive sequence is gained by using the ramp slope as a design parameter. The ramp sequence distributed over a certain period is temporally aligned to a given point in time. State estimation is done by minimizing a cost function. A significant advantage of a cost function approach is that ghost targets are suppressed directly. For test purposes a 77-GHz FMCW radar prototype is used in an automotive environment.