612 



DISPLAY SYSTEM DESIGN PROBLEMS 



Data Read-Out. In many applications — notably, airborne early 

 warning systems and semiautomatic bombing systems — the radar operator 

 functions as a data processor and filter. For example, in the AEW system 

 discussed in Chapter 2, the operator(s) might be presented with a display 

 of target azimuth, range, and height. The operator then is required to 

 "read out" these data in a form that can provide inputs for an air-to-ship 

 communications link. 



A general diagram of such a system is shown in Fig. 12-4a. The operator 

 "reads" the display, selects the desired information, and codes into a form 



Fig. 12-4a Data Read-Out System. 



suitable for communication and /or storage. This type of display problem 

 combines many of the features discussed in the previous applications. First 

 of all, the operator may have to use size, shape, and contrast information 

 to distinguish between desired and undesired data. He may also be required 

 to measure or estimate the coordinates of the target. Second, in applications 

 such as this, the operator usually is presented with a large amount of data. 

 Thus, many of the same considerations discussed for tactical situation 

 assessment and monitoring apply. 



Finally, the operator is expected to perform some function in a more or 

 less continuous fashion to keep up with the flow of data. This process 

 involves many of the same problems as the control function previously 

 discussed. The transfer characteristics of the operator — bandwidth, time 

 lag, etc. — are vitally important. These characteristics will, of course, 

 vary with the type of physical action required to accomplish the coding. 



An hnportant variation of the data read-out problem is shown in Fig, 

 12-4b. In this case, the displayed information is recorded photographically. 

 The operator then interprets the photograph rather than the display itself. 

 Many ground-mapping systems utilize display information in this manner. 

 Systems such as this permit time-scale changes between the rate of data 



Fig. 12-4b Data Storaee and Read-Out System. 



