A land-based smart sensor system and several system architectures for detection, tracking, and classification of people and vehicles automatically and in real time for border, property, and facility security surveillance is described. The preferred embodiment of the proposed smart sensor system is comprised of (1) a low-cost, non-coherent radar, whose function is to detect and track people, singly or in groups, and various means of transportation, which may include vehicles, animals, or aircraft, singly or in groups, and cue (2) an optical sensor such as a long-wave infrared (LWIR) sensor, whose function is to classify the identified targets and produce movie clips for operator validation and use, and (3) a supercomputer to process the collected data in real-time. The smart sensor system can be implemented in a tower-based or a mobile-based, or combination system architecture. The radar can also be operated as a stand-alone system.