Goodrich Sensor Systems has developed a Laser Perimeter Awareness System (LPAS) for surveillance that both detects the presence and tracks the motion of intruders, locating them in range, bearing, and elevation with respect to the position of the sensor. The system places graphic symbols representing the intruders onto a map or aerial photo at the appropriate locations. The coordinates of the intruders are available to cue additional sensors, such as thermal imagers, to automatically slew their fields of view toward the intruder for further investigation. Hence, security personnel can assess whether the detected intruder is a person, an animal, or simply a false alarm and take appropriate action. Detection performance as a function of object size is discussed.