Symmetricom Time Server Manual Do Utilizador

Chapter 4: Serial or Telnet I/O Functions

Use Function 60 to list current satellites and to see the relative signal strength of  satellites 
the unit is tracking.  Signal strength is given in units in the range of 0 to +25.

The unit monitors five variables: the prn number, good/bad, enabled/disabled, tracked, and 
current.

To request the list, send the following command:

where

F

=

ASCII character F

60

=

function number

<Enter>

=

input line terminator

The unit responds:

F60<SP>prn NN<SP>good<SP>enabled<SP>tracked<SP>current<SP> 
sig<SP>level<SP>= +<LEVEL><CR><LF>

where

prn NN

=

pseudo-random number;  the prn number is a unique 

identifier for a particular satellite’s communication 

path;  for example, satellite 3 might have the prn 

number 15;   if that satellite is recalled to Earth and 

replaced by satellite 42, the communication path of 

satellite 42 might also be assigned prn 15

enabled/disabled

=

“Enabled” refers to a factory default configuration 

value that allows the GPS to track all satellites on 

the F60 list

good/bad 

=

“Good” means all three of the following apply:
• the satellite is visible, and

• the satellite’s ephemeris and almanac data report 

the satellite’s health as “good”, and 

• the satellite reports its own health as “good”
“Bad” means at least one of the following applies:
• the satellite is not visible, or

• the satellite’s ephemeris and almanac data report 

the satellite’s health as “bad”, or 

• the satellite reports its own health as “bad” (for 

example, during maintenance periods)

tracked

=

“Tracked” means that the unit is tracking this 

particular satellite

current

=

“Current” means that the unit is both tracking this 

satellite and using the satellite’s communication to 

calculate accurate time;  an example from the list is 

prn 3

<CR><LF>

=

line terminator