Dual-Mode Anticollision Short-Range Radar

We propose a novel low-cost sensor able to determine the distance between a transmitter-receiver and a moving target (reflective flat area) for distances smaller than several meters. This quite simple sensor works at a single frequency and uses two different processes. The first one, based on interferometry, gives information about the phase difference of arrival; the second one is derived from Purcell´s method (image method) used in the gain antenna measurement. Such an anticollision method interests robotics.