Recently, the development of complex sensor networks has received considerable attention from the scientific society and industry, and many such systems have been implemented in different applications. Sensor networks consist of homogeneous or heterogeneous sensors spread in a global surveillance volume, acting joinly to optimally solve required tasks. Multiple target tracking is one of the most essential requirements for these systems; it is used to interpret an environment that includes both true targets and false alarms simultaneously. In spite of the great interest centered on fully automatic sensor data processing, the man-machine interface is nevertheless vital in such complex scenarios. This paper concerns spatio-temporal sensor data visualization and analysis for such complex systems, with a focus on components and data flow in sensor systems. Simplified examples illustrate the use of a developed graphic user interface and programming package for radar data processing.