imaging systems now used in many airborne applications. Operating in 

 the 10- to 15-|a region (LWIR) these passive, line scan systems develop 

 an image close to that obtainable with photographic resolution (e.g., 

 5-ft resolution from 50,000 ft) using the thermal ("blackbody") radiation 

 from surface objects. Such systems can provide nighttime coverage equiva- 

 lent to daylight airborne photo-reconnaissance. Although it is capable 

 of penetrating light haze, FLIR is subject to essentially the same cloud 

 cover/fog observation limitations as visual photography or TV. 



(3) Special Electrooptical Means 



If verification of licensing is of primary interest 

 to a surveillance program, two categories of shipborne optical verifica- 

 tion can be envisaged: passive and active. 



A very inexpensive (~$100) optical retroref lector 

 exhibiting spectral and/or polarization information coding could be 

 carried at masthead and interrogated by an airborne (eye-safe) laser 

 system "aimed" at the ship. The retroref lector does not require special 

 positioning and it can be readily detected by current technology systems 

 (in clear weather) at ranges of up to 50 miles. Coding could indicate 

 nationality, nature of authorized catch, and other simple multivalued 

 parameters. A somewhat more expensive (-^$1000) coded reflector, requiring 

 a small power input, could provide a vessel identification number and 

 other more complex data. 



The airborne interrogator (which could be fully 

 automatic in acquisition) would represent a nominal payload and power 

 drain (equivalent to, say, a surface search radar), would require some 

 engineering development, but would be essentially similar to present 

 target designators and trackers representing $100,000 to $200,000 unit 

 cost. Operational maintenance costs would be somewhat higher than for 

 airborne radio and radar equipment. 



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