How does it work? As a single-space monitoring system, PGS installs an ultrasonic sensor above each bay to detect bay occupancy. Occupancy data will be collected by the correspondent zone controller and be transmitted to the center processor, who will then process them and save them in the management center software database. After that, data(occupancy information) will be displayed on the various messages display system, such as LED signs, broadcast and internet to guide drivers to available spaces.