Range finding for multi-layered targets using NRD guide pulse radar system at 60 GHz

From the viewpoint of range findings of multi layers in a tank, pulse radar systems using millimeter-wave frequencies are preferable for such multi-reflection environment because pencil beam patterns can be easily obtained. With this in mind, pulse radar front-ends using an NRD-guide technology were fabricated. And moreover, an FPGA-based digital signal processor including high-speed counting, memorizing, and averaging was developed to remove range-finding error due to multi-reflection between the radar and the target. Based on this technique, a simple range finding test was performed. This signal processor however could not detect distances to multi-layered targets. This paper presents improvement of the signal processor to recognize reflected pulses from the multi-layered targets and to precisely detect the measurement distance by using the sequential sampling.