ILLUSTRATIONS 



1 1980 Ship Distribution 22 



2 Remote Sensors Using Electromagnetic Energy 28 



3. Predicted Ocean Surveillance Radar Performance 41 



4. Useful Surveillance Coverage by a State-of-the-Art 



Microwave Radar on a 70-kft Altitude Aircraft 44 



5. Airborne Scanning Microwave Radiometer 52 



6. Microwave Brightness Temperature of the Sea Compared With 

 a Perfectly Reflecting Vessel and a Perfectly Absorbing 



Vessel at 20 GHz 53 



7. Total One-Way Vertical Attenuation for a Transit of the 



Entire Troposphere 59 



8. Attenuation in Rain and Fog 61 



9. Ground-Based HF DF Performance 83 



10. Typical Area Overview 92 



111 



