Simple Pedestrian Detection Secondary Radar Using Frequency Doubling

This paper describes a simple secondary radar for detection of hidden pedestrians, by using a compact transponder which responds to a radio-wave transmitted from a car. The transponder doubles the frequency of the radio-wave for frequency-domain duplexing with a simple configuration. The distance between the car and the pedestrian can be measured by using a phase detection scheme, with no local oscillators at the pedestrian side.