Patent ID: 10984615

Abstract:
A system for accessing or providing operational control of a vehicle includes initiator and sniffer devices. The initiator device includes: polarized antennas; a transmitter transmitting a first tone signal via the polarized antennas from the vehicle to a responder/portable access device; and receiver receiving a second tone signal from the responder device in response to the first tone signal. The sniffer device includes: second polarized antennas; and a second receiver receiving, via the second polarized antennas, the first tone signal from the transmitter and the second tone signal from the responder device. The sniffer device determines states of the first and second tone signals including respective phase delays. The initiator or sniffer device estimates a first distance from the vehicle to the responder device or a second distance from the responder device to the sniffer device based on the states including respective phase delays.