2 ELEMENTS OF AIRBORNE RADAR SYSTEMS DESIGN PROBLEM 



The analysis of these examples presents a basic method of approach which 

 involves the concept of balancing various system elements — a procedure 

 that can and should be used in the design of any airborne radar system. 



Perhaps the most important concept that must be grasped by the radar 

 designer is this: A radar is usually a small but vitally important part of a 

 dynamic system, i.e., a system whose basic characteristics and parameters 

 are constantly changing functions of time. Because of its role as the 

 "eyes" of the system, the dynamic performance of the radar must be 

 related to — and to a large extent, governed by — the dynamic perform- 

 ance required of the entire system. For this reason, the radar designer must 

 possess the capability for understanding and analyzing the overall weapons 

 system in addition to his specialized knowledge of the details of radar 

 systems analysis and design. 



1-2 CLASSIFICATIONS OF RADAR SYSTEMS 



In order to provide background for the discussion of the systems aspects 

 of airborne radar design, the basic characteristics and uses of radar systems 

 are described. Many of the descriptive terms commonly used in radar 

 system technology are defined. Some of the simpler mathematical expres- 

 sions that arise in radar work are presented. 



Radar is a word derived from the function performed by early radar 

 systems — RAdixo Detection And, /hanging. The word was meant to denote 

 systems that transmitted and received radio signals. Today the meaning 

 of the word has been extended to include a wide variety of systems that 

 employ microwave techniques. It encompasses systems using received 

 energy originating in the system (active systems), systems using received 

 energy originating at the target (passive systems), systems using received 

 energy originating at a transmitter separate from the receiver or target 

 (semiactive systems), and systems emitting electromagnetic radiations for 

 various purposes (transmitting or illuminating systems). Many complex 

 weapon systems include combinations of these basic types. For example, 

 an electronic countermeasures system may be composed of a passive radar 

 system that detects the presence of hostile electromagnetic radiation and 

 utilizes this intelligence to control the action of a jamming system to combat 

 the enemy radiation. 



The profusion of radar systems in use today requires that some logical 

 means of classification be employed. One such means that has achieved 

 general acceptance classifies a radar system according to the four character- 

 istics: 



1. Installation environment 



2. Function(s) 



