An intrusion system can be configured to includes a detection module comprising a processing module and a sensor having an output coupled to the processing module, wherein the detection module is configured to detect an object in a predetermined area and to determine a position of the detected object in the predetermined area an ultrasonic generator comprising an oscillator configured to generate an ultrasonic signal and an ultrasonic emitter coupled to the ultrasonic generator configured to launch an ultrasonic wave toward the position of the detected object.
