104 THE DEVELOPMENT OF WEAPONS SYSTEM REQUIREMENTS 



during a battle is 48 — 12 combat air patrol and 36 deck launch — out of a 

 total complement of 66. The combat air patrol interceptors maintain 

 station for 2.8 hours. 



These considerations coupled with the interceptor kill-probability goal 

 are the principal factors that determine required interceptor system 

 reliability during the attack operational situation. 



The AI radar and fire-control system may be expected to be the primary 

 contributors to interceptor system unreliability — recognizing that the 

 guided missiles' reliability has already been included in the specified missile 

 kill probability. On this basis, we shall assume for purposes of specification 

 that failures in the AI radar and fire control will cause two-thirds of the 

 aborts due to equipment failure. Since we specified the overall reliability 

 of the interceptor system as 0.85, the reliability requirement for the AI 

 radar and fire-control system is 0.90. 



A reliability requirement has little meaning unless the element of time is 

 included. Based on the large number of CAP interceptors that must be 

 kept continuously aloft, it is specified that the reliability requirements shall 

 be met for any 3-hour operating period. Chapter 13 will discuss the 

 implications of this requirement, the type of design techniques that must 

 be employed to meet it for the defined environmental conditions, and the 

 means for determining whether a given radar can meet such a requirement. 



2-24 PROBABILITY OF VIEWING TARGET — VECTORING 

 PROBABILITY 



The study plan — as extracted from the master plan of Fig. 2-26 — is 

 shown in Fig. 2-27. The object of the study is to derive the combinations 

 of the variable elements that will permit achievement of the assumed 

 performance goal and to ascertain the sensitivity of vectoring probability 

 performance to changes in the system parameters. 



From Fig. 2-26 it can be seen that several variable factors — notably 

 lock-on range and look-angle (maximum gimbal angle) — are common to 

 conversion and vectoring probability. Accordingly, we cannot develop 

 firm requirements for these in this phase of the study. Rather, the results 

 will be expressed as a spectrum of possibilities, all of which satisfy the 

 viewing probability requirement. Later we shall determine the portion of 

 these possibilities which also satisfy the conversion probability require- 

 ments. 



Search for the target and its detection obviously must precede AI radar 

 lock-on. Thus, these factors are functions of the lock-on range and cannot 

 be specified until lock-on range is specified. 



AI radar search data display and stabilization and search doctrine are 

 dictated almost entirely by vectoring phase considerations. Thus, these 

 may be specified by the analysis of the viewing probability problem. 



