The implied directions, for (fi < 0, are directly opposite from those 

 for (|) ^ so that for a given value of ((> £ we get directions (a < 0) 



and 



e. = "^i-^ -^ 



as before. 



Thus, where the principle value of arcsin is assumed, we get a set of 

 possible directions 



"It 



where 



K= % ^ [f + "^^ 



o6^=i ARC&I 





(7.6) 



h being constrained by 





An example of this type analysis, for an array pair, is illustrated 

 in Figure 6. Thus several estimates of 6q are available (at least two). 



The estimates of true direction, Gq, often vary from one array 

 element pair to another, making the selection of a true Qq value diffi- 

 cult. The selection is also hindered because half of the estimates of 

 0Q are of the image type; i.e., false estimates. 



While the above directional method leaves something to be desired, 

 it does illustrate the basic directional information produced by an 

 array of detectors . 



A better method, suggested in Munk et al (April 1963) , of using the 

 spectral matrix directional information to fit a single wave at each 



29 



