capture - A process spawned by tsched to receive and process satellite data

SYNOPSIS

capture chain pass satel telem date time durat script ant|noant [now]

Additional input provided by environment variables LIVEPROC and PASSGAP.

DESCRIPTION

capture is the process started by tsched to receive and process satellite data. Depending on its input parameters, capture has up to three important subprocesses: antenna tracking, telemetry framing, and data post-processing. Antenna tracking is started only if the noant option is not used. Post processing is started only if script is not blank or is not equal to none.

capture gives the 1-relative number of the pass to the post-process via the environment variable $LASTPASS.

If the environment variable $LIVEPROC is defined, capture starts up any post-process 5 seconds after starting up the telemetry framing process. If $LIVEPROC is not defined, capture executes waitpass pass_number=$LASTPASS prior to running the post-process. This means that the post-process is not started until reception completes.

tsched normally starts up capture 45 seconds before scheduled reception if antenna tracking is required, or 5 seconds otherwise. However, the user can use the PASSGAP environment variable to set the number of seconds capture is to be started ahead of schedule.

PARAMETERS

chain

1-relative telemetry chain number.

pass

1-relative pass disk number

satel

satellite name, e.g., noaa-14

telem

telemetry name, e.g., hrpt

date

start date, yy/mm/dd

time

GMT start time, hh:mm:ss

durat

pass duration, hh:mm:ss or mm:ss

script

post-process script, or none

ant|noant
 
antenna control/no-control flag
now
 
receive data as if start time was now

SEE ALSO

tsched, antenna, rdframe, waitpass

NOTES

Multiple post-processing scripts can be entered at once using semi-colon or ampersand separators, e.g.

"script1 [;|&] script2 [;|&] script3"

If a script is followed by a semi-colon, it is run in the foreground. If a script is followed by an ampersand, it is run in the background. Consider the following example:

"script1 ; script2 & script3"

script1 is run in the foreground. When script1 completes, then script2 is run in the background. script3 is started in the foreground at the same time as script2 is started in the background.


Last Update: $Date: 2001/05/16 17:34:45 $