44 ELEMENTS OF AIRBORNE RADAR SYSTEMS DESIGN PROBLEM 



to the whole. In the example of the interceptor system previously referred 

 to, we might have the following models. 



1. System Flow Model illustrating the qualitative aspects of system 

 operation. 



2. Overall System Effectiveness Model indicating in gross terms the 

 defense level that could be provided against a multiplane attack. 



3. Early Warning Detection and Tracking Model indicating the 

 quantitative aspects of the problem of early-warning detection, 

 identification, tracking, and target assignment. 



4. Interceptor-Bomber Duel Model, including (a) Vectoring Model, 

 (b) Airborne Radar Detection Model, (c) Attack Phase Model, 

 and (d) Target Destruction Model. 



Each model must be logically consistent with the others, to maintain 

 a unified systems approach. Constructing these models shows the same 

 stages as constructing the overall system, namely, 



1. Define input variables. 



2. Define performance criteria ("mission accomplishment goals"). 



3. Outline system logic. 



4. Define the configuration parameters of the part of the system 

 being analyzed. 



5. Derive the quantitative relationships on the basis of the input 

 parameters, system logic, and configuration parameters. 



This process of analyzing only a small portion of the system problem 

 at any one time is known as suboptimization. Successive suboptimizations 

 of various portions of the system can form a step-by-step approximation 

 which converges to the results that would be obtained if one could analyze 

 the entire system with one model. 



Counterbalancing the obvious analytical advantages of the suborpti- 

 mization technique is the fact that it gives rise to a serious bookkeeping 

 problem. The results of each suboptimization process must be logically 

 consistent with the rest. As we successively suboptimize various portions 

 of the system, the assumptions of previous suboptimizing routines may be 

 changed. We must recognize such changes and modify previous sub- 

 optimization routines to be consistent with these changes. Summary 

 tables, information flow diagrams, and functional block diagrams form 

 indispensable tools for the bookkeeping process. 



1-13 SUMMARY 



In this chapter, we have covered the general characteristics of radar 

 systems; the environments in which they operate; the functional capabilities 



