Perimeter surveillance radar (PSR) is a class of radar sensors that monitor activity surrounding or on critical infrastructure areas such as airports,[1] seaports, military installations, national borders, refineries and other critical industry and the like.
Such radars are characterized by their ability to detect movement at ground level of targets such as an individual walking or crawling towards a facility.
These have the potential for very high target position accuracy, however they are less effective in the presence of fog and other obscurants.
[3] To a degree, Doppler based radar can detect movement in such areas, as long as the component of movement velocity towards or away from the radar is significant enough to generate a signal that overcomes the foliage return signal.
Many PSRs directly interface to control daylight or thermal cameras using a "slew to cue" system to overcome this problem.