5-11] DETERMINATION OF SIGNAL'S TIME OF ARRIVAL 291 



but only about half as great. Actually, the estimate in Equation 5-156 is 

 optimistic. The mechanism by which the maximum value is chosen can 

 introduce additional errors; nor was any consideration given to the effect 

 of target fluctuations which would act to increase the error. As a typical 

 case, if the signal-to-noise ratio out of the matched video filter as given by 

 Equation 5-153 is 6 db, the rms angle error from Equation 5-156 is 



rms angle error = e/2.35^[4', z'~ = 4 (5-157) 



= 0.2139. 



In Paragraph 2-15 it was assumed that the target angle could be determined 

 in a scan to 1 /4 of a beamwidth. From the relation above, this is not an 

 unreasonable assumption. 



