The outgoing and return pulses of the echo sounder gate a 25- 

 kilocycle signal on an electronic counter, resulting in digitized values 

 of distance to the surface directly in feet and tenths. 



5. Data format 



a. Mode 1 (Routine) 



The complete data message, which may be recycled as often 

 as every two seconds, consists of 36 digits of data and six channel 

 identifiers. While the format may be* changed to a prearranged set of 

 rules, the following example is a typical data message as would be 

 received from the digital recorder. 



6 2 3 3 5 



5 4 9 7 1 



4 2 2 4 3 



3 5 7 6 5 5 



2 13 3 8 

 11118 2 7 



The first vertical column represents the channel indicator. Channel 

 1 is GMT time: 11 hours 18 minutes 27 seconds. The first three digits 

 of Channel 2 indicate the day of the year: the 130th day is 9 May; the 

 next digit is the octant of the globe: Octant for 0° to 90°W. north 

 latitude as in the World Meteorological Organization code; and the 

 last two digits are degrees of latitude: 38°. The first two digits of 

 Channel 3 are minutes of latitude: 50'; these are followed by degrees 

 and minutes of longitude: 76°55'. Channel 4 shows the depth of the 

 submarine in feet and tenths: 224.3 feet. Channel 5 indicates the sound 

 velocity in feet per second: 4,971 feet per second. Channel 6 is the sea 

 temperature in degrees and hundredths Centigrade: 23.35°C. The sign 

 of the observation is given by the first digit following the channel 

 indicator: = positive, 1 = negative. 



b. Mode 2 (Diving) 



The complete data message is similar to that from Mode 1. 



6 2 3 3 5 



5 4 9 7 1 



4 2 2 4 3 



3 5 2 5 

 2 13 3 5 

 11118 2 7 



C-7 



