84 THE DEVELOPMENT OF WEAPONS SYSTEM REQUIREMENTS 



Beamwidth 5° 



Pulse length 12 /xsec 



Scan time 10 sec 



These characteristics coupled with assumed values for quantization levels 

 in the AEW and the CIC systems and the assumed limits for stabilization 

 errors and time-delay errors lead to the following accuracy characteristics 

 for the provisional AEW system. 



a A = (3.3) X (1.04) X (1.10) X (1.10) = 4.15 n. mi.rms 



(at 150 n.mi. range) 



CA = (1.65) X (1.04) X (1.10) X (1.10) = 2.07 n.mi. rms 



(at 75 n.mi. range) 



aR = (0.25) X (1.04) X (1.41) X (1.10) = 0.41 n. mi.rms 



(unaffected by maneu- 

 vers and range). 



(2-7) 



The total rms position errors may be expressed as the vector sum of the 

 range and azimuth errors or 



<TT = (c7a' + (TR^y = 4.17 n. mi. (150 n.mi. range) 



= 2.09 n. mi. (75 n.mi. range). (2-8) 



One source of error — the 1 n.mi. rms navigation error of the AEW 

 aircraft (see Paragraph 2-11) — has not been included in this analysis. 

 This error is not significant when all of the target and interceptor tracking 

 data come from a single AEW aircraft and when the navigation error 

 changes vary slowly with time. When these conditions prevail, each piece 

 of data in CIC will be biased by the same error. The relative errors between 

 pieces of data are therefore unaffected. As we shall see, it is these relative 

 errors that determine tracking and vectoring accuracy. 



The navigation error does become important for targets and interceptors 

 which are tracked by both AEW radar aircraft. Such an overlapping zone 

 is shown in Fig. 2-18. A large navigational error would complicate the 

 problem of correlating data from the same target. However, since the 

 navigation error is less than the measurement errors and less than aircraft 

 separation distances, no great amount of difficulty can be expected for 

 this hypothetical case. 



2-16 INFORMATION-HANDLING CAPACITY OF THE 

 PROVISIONAL AEW SYSTEM 



An important aspect of system design relates to its data-handling 

 capabilities. Both the data link for transmitting information between the 



