Position-sensitive alarm system

A vehicle alarm system adapted for installation in a vehicle having

• a warning device (41, 42) triggerable upon detection of a disturbance to the vehicle and
• comprising
• at least one position sensitive sensor (10, 10') furnishing repetitively, continuously sequentially position output signals representative of the position of the vehicle on a support surface;
• data storage means (30, 51) connected to and receiving the position output signals from said sensor, and storing data representative of the position of the vehicle on the support surface;
• comparator means (34, 53) connected to said data storage means and said position sensitive sensor and receiving stored data indicative of a prior position of the vehicle as represented by a prior position output signal as well as a then furnished position output signal, and comparing said prior and then furnished signals for detecting a deviation of the position output signal furnished by said sensor (10) from a stored value retained in the storage means,
• said comparator means furnishing a triggering signal to said warning device (41, 42) when said deviation of position exceeds a predetermined amount to provide a warning when a disturbance of the position of the vehicle with respect to a prior position on said support surface is sensed by said sensor.