A surveillance problem which has already been addressed is that 

 of tracking distant ship targets with sonar (figure 6). Tlie live 

 atlas file has been used to retrieve sound velocity profiles along 

 a great circle route connecting a transmitter and target. The IISOC 

 has, on repeated occasions, utilized the retrieval software to ex- 

 tract information of this type from the North Atlantic sound velocity 

 file. 



PROCESSOR 



FAST MEMORY 

 (DISC, DRUM, ETC) 



-Q 



\ SLOW MEMORY 



I (MAGNETIC TAPES) 



I 



REMOTE DISPLAY STATIONS 



Figure 1. A Projected Live Atlas Hardware Scheme 



312 



