A passive entry system for an automotive vehicle that is configured to prevent relay attacks by analyzing magnet vectors and angles created by a plurality of antennas mounted on the vehicle is disclosed. A vehicle including a control unit configured to broadcast a wake-up signal to prompt a fob to power-up if the fob is in a low-power consumption mode and to transmit signals through a plurality of antennas coupled to the vehicle is provided, along with a fob configured to recognize the wake-up signal and to generate a response signal for the control unit in response to recognize the wake-up signal. The fob includes a controller that is programmed to receive signals transmitted from each of the plurality of antennas coupled to the vehicle, retrieve constant values from stored a memory, and calculate a magnetic integrity defining the relative position of each of the plurality of antennas. The controller allows access to the vehicle if magnetic integrity is found, and denies access to the vehicle if magnetic integrity is not found.