Abstract: A motor vehicle having a remotely operable subsystem provided with an acoustic emitter has a system having a microphone on the vehicle, a signal processor connected to the microphone for determining an ambient sound level at the microphone, and a controller connected between the signal-processor and the acoustic emitter for controlling an output volume of the emitter in accordance with the determined ambient sound level at the microphone.

Abstract: A monitoring of a vehicle interior is effected by detecting sound waves in a vehicle interior, either from an incursion source or as reflected as echo waves and decomposing the electrical signals representing those detected sound waves into measurement vectors which are compared with sample vectors in a neural network so that a correlation parameter is generated which triggers an alarm when the correlation parameter indicates incursion. The system can respond first to glass breakage before an echo system is used to then further establish the nature of the incursion.