TABLE OF CONTENTS Surveillance
Choosing parameters
Radar cross-sections of targets and clutter
Final design
An attempt to design a surveillance radar reveals how difficult it is to watch the whole sky.
Marine radar, air traffic control, air-borne radar defence systems, ground-based radar arrays searching for satellites in space -these are all well known examples of radar surveillance systems that work in all weather conditions, and at all times of day, testifying to the versatility of the radar technique.
Most modern surveillance radars are multifunction , jargon for their capacity to carry out other activities at the same time as searching for new targets. One of these functions is to keep track of existing targets until they are within a certain distance of the radar, when an entirely separate system takes over: at a civil airport, for example, a Terminal Area radar guides in the planes; a ship under attack, on the other hand, might engage a close support weapons radar to lock on to the target. In this chapter we are going to concentrate on one of the main applications of surveillance radar, which is to search the sky continuously for new targets.
Surveying the sky presents the radar design engineer with something of a dilemma; the radar needs to scan the whole sky and get back to the starting point as quickly as possible in order not to miss any new developments. However, the radar also needs to spend as much time as possible staring...
