Summary of AVHRR acquisition and scheduling systems
AUTHOR: Tim Baltzer
Current system
- Live acquisitions are accomplished via the antenna on the roof.
(Approx 3 scenes per day per satellite)
- DOMSAT acquisitions are accomplished via the DOMSAT dish in the
front yard (Approx 20 scenes per day, or 1 Gig of data).
- All of the acquisition software resides on VAXH. This software
ultimately transfers acquisitions to edcsgs4 for processing.
- The master schedule resides on VAXH in ADAPSTABLES.
- All schedule directive files to modify the master schedule are
sent to VAXH.
- The VMS command procedure "update.com" runs on VAXH to process
schedule directive files and modify the master schedule accordingly
(via SCHEDIT).
- Entries are added to the master schedule by Data Management personnel.
- Any auditing (deleting of old scenes, etc.) in the master schedule
is accomplished manually by Data Management personnel.
- The MISSFTP daemon runs continuously on edcsgs4 to recover any missed
live or missed DOMSAT scenes via ftp from a NOAA server. If available,
these scenes are left on the NOAA server for a 24 hour period.
There are about 2 scenes per week recovered in this manner.
Future system
- Live acquisitions are still accomplished via the antenna on the roof.
- DOMSAT acquisitions are accomplished via the DOMSAT dish in the
front yard OR via ftp to a NOAA server (most likely).
NOAAFTP is the daemon written to download DOMSAT scenes from the NOAA
server. NOAAFTP will also recover missed local acquisitions from the
NOAA server, thus making MISSFTP obsolete.
- The master schedule resides on edcsgs4 in ADAPSTABLES.
- All schedule directive files to modify the master schedule are
sent to ADAPSTABLES on edcsgs4.
- Anytime the master schedule is modified on edcsgs4, it will be copied
to VAXH so that an up-to-date copy will always reside in ADAPSTABLES
on VAXH. This copy is needed on VAXH to control live antenna acquisitions,
and DOMSAT antenna acquisitions (if being used). The master schedule on
VAXH is NEVER copied back to edcsgs4, even if it is updated by the
acquisition software on VAXH.
- The UPDATESCH daemon runs on edcsgs4 to process schedule directive
files and modify the master schedule accordingly (via SCHEDIT).
- Entries are still added to the master schedule by Data Management personnel.
- Auditing (deleting of old scenes, etc.) of the master schedule is
accomplished automatically by the AUDITSCH daemon. AUDITSCH will
generate schedule directive files which will be incorporated into
the master schedule by UPDATESCH.
Toggling between DOMSAT acquisition systems:
Using the local DOMSAT dish:
- Must have the two INHALE processes running on VAXH.
- Run AUDITSCH with CEOSIDS=SFL,NGC,NOA.
This will enable the software on edcsgs4 to look in the ingest logs
to determine when live and DOMSAT scenes have been acquired on VAXH
(and generate schedule directive files to update the master schedule
to signify the scenes have been acquired).
- Run NOAAFTP with TIME_ACQ=180 minutes or more. Extending this time
will prevent NOAAFTP from downloading scenes before they get
transmitted to the DOMSAT dish (NOAAFTP should only be downloading
MISSED acquisitions when utilizing the DOMSAT dish).
Using the ftp link to the NOAA server:
- Must NOT have the two INHALE processes running on VAXH.
- Run AUDITSCH with CEOSIDS=SFL. When NOAAFTP downloads a scene from
the server, it will generate a schedule directive file (to update
the master schedule to signify the scene has been acquired).
AUDITSCH only needs to look in the log files for SFL scenes to
determine when they have been acquired.
- Run NOAAFTP with TIME_ACQ=60 minutes (start looking for NGC scenes,
NOA scenes, missed SFL scenes on the NOAA server 1 hour after their
acquistion time).
A word about schedule files in general:
The master schedule file contains ascii records, each record describing
the status of a scene id. Schedule directive files are also ascii files
and describe actions to be performed on the master schedule file. These
actions are performed by SCHEDIT (schedule editor). The following
schedule directive files are possible:
add - scenes to be added to the schedule
delete - scenes listed by date to be deleted
delsid - scenes listed by scene id to be deleted
modify - scenes to be modified based on date range
modsid - scenes to be modified based on scene id
modsta - scenes to be modified based on date range
and station
sort - indicates the schedule is to be sorted