132 THE DEVELOPMENT OF WEAPONS SYSTEM REQUIREMENTS 



Choose 

 Aspect Angle 



Pick a 

 Lock ■ on Range 



Determine 



Collision Course 



Lead Angle 



(Fig. 2-48) 



Determine Vectoring 



Distribution About 



Collision Lead Angle 



(Fig. 2-32) 



1 £ 



Establisii 

 Distribution of 

 Heading About 

 Collision Course 



Establish Distribution 



of Headings About 



Lead Collision Course 



(Fig. 2-51) 



Determine 



Lead Collision 



Lead Angle 



(Fig. 248) 



r 



Establish 



Percentage of 



Distribution Which 



Can Convert 



Probablity of 

 Successful Conversion 



Determine 

 T-ff 

 (Fig. 247) 



^ 



Determine Magnitude 



of Steering Error 

 Which Can Be Reduced 

 (Fig. 249 ) I 



Fig. 2-50 Conversion Probability Analysis Plan. 



Aspect angle at lock-on = 60° 



Lock-on range = 8 n.mi. 



Collision-course lead angle = 35° 



Vectoring distribution, ae.r = 21.5° 



Lead collision-course lead angle, L = 26.5° 



T - tf = 20.5 sec 



Maximum correctable steering error = 36° 



Fig. 2-51 shows the distribution of heading errors relative to the correct 

 collision and lead-collision courses. Since an error of 36° may be corrected, 

 any initial heading which results in a lead angle between 62.5° and —9.5° 

 may be converted into a successful missile launch. Thus, the probability 

 of conversion is equal to the shaded area sh jwn, which may be determined 

 as 88.5 per cent. 



