1. A method to find a location where an object crosses a path between two devices, the method comprising: performing high-resolution ranging between the two devices, wherein each device includes one or more antennas, wherein the one or more antennas are connected to a transmitter or receiver of the corresponding device by a RF switch or a switch array, wherein the two devices are separate devices that both transmit and receive RF signals; and determining the location of the object between the two devices by correlating a change in distance of at least one RF path between the two devices.