Table 11 



BASELINE RADIOMETER SHIP DETECTION SYSTEM 



(3) Maximum Range for Detection and Platform Altitude 



Maximum microwave sensor range is constrained by 

 the fact that successful detection requires an adequate ratio between 

 the solid angle subtended by the vessel and the antenna beam -solid angle. 

 Several different criteria are used to determine the maximum range at 

 which detection can be effected. All of these criteria lead to about 

 the same maximum range. We will adopt the criterion that the effective 

 radiometric area of the vessel equals at least 10% of the area viewed 

 by the antenna beam. The maximum allowable range, R, is then given by 



4 A 



R = 



(Q^^^n(0.01745a^/2)2 



where 



R = maximum range for detection, ft 



A = effective radiometric area of vessel, ft 



e 



a . = antenna beamwidth at 3-dB points, deg. 



62 



