Abstract: An apparatus (10) and method are provided for detecting an intrusion into a predetermined area. The apparatus (10) includes a transmitter (28) for transmitting a signal within the predetermined area. A first receiver (30) is oriented toward a first location within the predetermined area and receives reflected return signals of the transmitted signal. A second receiver (32) is oriented toward a second location within the predetermined area and receives reflected return signals of the transmitted signal. The second location is different from the first location. A controller (42) determines whether reflected return signals received by the first and the second receivers (30 and 32) indicate an intrusion or a non-intrusion event. The controller (42) provides an alarm signal for an alarm (44) when only one of the reflected return signals received by the first and the second receivers (30 and 32) indicates an intrusion.

Abstract: A vehicle (12) includes an ultrasonic intrusion alarm system (11). A linear electric motor (60) has a movable part (64) that moves linearly relative to the alarm system (11) upon actuation of the linear electric motor. A computer (120) controls operation of the linear electric motor (60). A plurality of different test devices (80, 90, 100, 110) are selectively connectable with the movable motor part (64) for performing different tests of the alarm system (11).