RESULTS IN PORT 



Whenever the survey ships were in port, available 

 Omega signals were monitored. These data are especially 

 valuable since the positions of the ships were carefully 

 determined, * Most of the in-port data were measured by 

 the respective navigators and forwarded to NEL for analysis. 

 The data have proved to be virtually free from incidental 

 errors and nearly always significant. 

 Slaved Phase differences were measured in 24 ports of call 



transmissions from 10.2-kc/s transmissions in the "slaved" mode. As 



measured in 24 changes in the transmission schedule caused unusual lines- 



ports of call of -position to be available at various times and since some 



of the ports were revisited, more data were obtained than 

 might be expected from single visits using existing equip- 

 ment. Also, manual and automatic time sharing were used 

 60 site-LOP's for a few measurements. The net result was that 60 site- 



LOP's were obtained using five different lines-of-position. 

 The average monitoring duration was three days. 



Half- hourly readings from a typical phase differ- 

 ence recording are shown in figure 3. The scatter on the 

 graph is that actually displayed on the original recordings 

 since no time averaging was used in the reduction. The 

 scatter is indicative of the receiver time constant of about 

 30 seconds. For the particular measurement shown in 

 figure 3, all component propagation paths are dark between 



*Each position determination was referenced to local datum. 

 Accurate conversion to international coordinates could not 

 be made for all locations. The overall error resulting from 

 inadequate geodetic information is believed small although 

 probably appreciable. Errors at individual sites, however, 

 may be important. 



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