1 2-8] DEVELOPMENT OF REQUIREMENTS FOR A DISPLAY SYSTEM 6S 1 



Surmnary. This paragraph has discussed some of the characteristics of 

 the visual system of the human operator and has indicated the kind of 

 analysis, experimental and logical, that is required if the human operator 

 is to be properly integraied into the system design. 



12-8 DEVELOPMENT OF REQUIREMENTS FOR A 

 DISPLAY SYSTEM 



In this paragraph, the use of the data and considerations relating to 

 display system design will be illustrated by the development of a possible 

 solution to display system problems for the airborne intercept mission 

 originally defined and discussed in Paragraphs 2-22 through 2-30. To 

 recapitulate, the interceptor is vectored towards the target on a collision 

 course, until the target is detected. Upon detection, the pilot locks his radar 

 on the target, converts from an approach to an attack course, guides the 

 aircraft on this attack course, and launches his weapon at the appropriate 

 time. The weapon is assumed to be an air-to-air missile with semiactive 

 homing guidance. During the missile flight, the radar must remain locked- 

 on to provide illumination for homing although the aircraft itself may make 

 moderate turns off the attack course after launching. 



Search and Vectoring Display. In Paragraph 2-26 and in Fig. 2-29, 

 the quantities which must be displayed to the pilot during the vectoring 

 phase are specified. These quantities are (1) the target altitude, (2) time 

 to collision, (3) the relative range to the target, and (4) the interceptor 

 heading commands. In addition, of course, the video information itself 

 must be displayed to provide the detection function along with aircraft 

 attitude information and the antenna look angles. It is very difficult to 

 provide all this information in one display, particularly on a single scope 

 face, without generating a great deal of confusion. One possibility is to 

 present some of the auxiliary data which change slowly on either counters 

 or dials rather than directly on the scope face. This can be done with target 

 altitude, the time to collision, and the range to the target. Accordingly, 

 we shall require these three quantities to be displayed numerically on 

 separate counters. The information which must now be combined on one 

 scope are (1) the video signal for target detection, (2) a vectoring heading 

 command, (3) aircraft roll and pitch and (4) the antenna look angles. 



The video presentation which has been found most satisfactory for this 

 type of application is an azimuth-range B scope. The AI requirements 

 summarized in Sec. 2-30 specify that the search pattern be 60° in azimuth 

 and 17° in elevation with a search range of 20 n.mi. The total look angle 

 can be ±60° in both azimuth and elevation. 



A 7-inch scope will be preferred for an AI application of this type where 

 space is very limited. This will provide a 5-inch square for the B display. 



