1-9] SYSTEMS ENVIRONMENTS 35 



In the technical requirements analysis phase, all possible ingenuity should 

 be employed to minimize radar complexity for a given weapons system capa- 

 bility. This is one of the most important reasons why the radar system 

 designer must analyze the radar problem as a weapons system problem. 

 Important performance benefits can be achieved by making the proper 

 reliability-complexity trade-off early in the game. 



Summary. The systems approach to radar design implies that the 

 radar is considered in its relation to the construction and objectives of the 

 entire weapons system during all phases of its conception, design, construc- 

 tion, and use. The radar systems designer must participate in all phases 

 of the development; he must demonstrate a good understanding of the 

 overall system and the characteristics of its other components prior to 

 laying out a radar design. 



To increase the reader's understanding of the basic features of the systems 

 approach to airborne radar design, several of the points presented will be 

 amplified in succeeding paragraphs. These include a more precise definition 

 of the system environment and its eflFects upon the problem, and a brief 

 discussion of the concepts and processes involved in the construction of a 

 weapons system model. 



1-9 SYSTEMS ENVIRONMENTS 



In this book, the "expected tactical conditions of operation" include 

 all of the following environments. 



1. Tactical Environment — The salient elements of this environment 

 are the speed, altitude, operating characteristics, and mission profile of the 

 airborne portion of the weapons system; the composition, operating char- 

 acteristics, and relative position of the ground-based portion of the weapons 

 system; and the characteristics (speed, course, altitude, number, physical 

 size) of the target complex. 



2. Physical Enivronment — The salient elements involved are tem- 

 perature, pressure, humidity, precipitation, fog, salt spray, wind, clouds, 

 sand, and dust. In systems requiring a human operator, the physical 

 environment will include factors affecting his ability to operate the system. 

 Among these are habitability, ease of operation, length of attention span 

 required, and the physical readiness and mental acumen required. 



3. Airframe Enviromnent — The salient elements involved are volume 

 and configuration of allotted space within the airframe, weight limitations, 

 vibration, and shock. 



4. Electronic Environment — This includes all the external sources of 

 electromagnetic radiations and electromagnetic radiation distortions and 

 anomalies. Examples are ground, sea, and cloud clutter; radiation from 



