Control and Processing

Back to Satellite Top CONTROL AND PROCESSING
Wireing schematic

The figure above is a diagram of the system wiring. Data flows from the satellite dish through the communications room, to the final products that are distributed through the MBARI network. Detailed description of each of the components is below.

Daily Operations

To understand and learn about the daily maintenance and operations of the MBARI system, please look at The Care and Feeding of the Satellite System , Reiko Michisaki's Step by Step Instructions.

Hardware

Satellite Dish
Satellite Controller system
Telonics receiver and Orbital Science decoder
Foam workstation

HRPTDI Data Ingestion
HRPTPG Product Generation
HPPTPD Product Distribution
HRPTDS Data Storage
Logins
Contacts
Tape back up system

Foam File system
Data path.

Lepas workstation

Satellite Dish

The Satellite dish is a "Tiris" model THRPT-6 1.5 meter dish manufactured by Telonics Corp. The owners manual for this can be found in Office number 256, on the bookshelf to the right of the door. This is a completely self contained unit, receiving all power and commands from the control unit in the communications room. Although this is a very low maintenance system, after 3 to 5 years, the gear box may begin to wear out and need replacement. The indicator for this is that the antennae will not move smoothly but will "jump" along its positioning path.

Controller

The Satellite control system is a set of hardware that includes FOAM, the THRPT antenna controller, and a BNC box. FOAM keeps track of which satellites to track and download data from. FOAM does this by retrieving the satellite overpass times and orbital elements from an ftp server (ftp.cerf.net) each day at 8:34 AM local. When a satellite comes into view of the antenna, FOAM starts the antennae controller in the Telonics SCSI box, tracks the satellite, and starts the flow of data. Azimuth and altitude antenna motor control is accomplished with the Telonics THRPT 6S Antenna controller. The control box provides power and directional control to the antenna motors from within the control room, thus eliminating the need for a power source or control hardware outside with the antenna. Satellite data from the antenna then flows through the BNC cable and BNC adapter box to SCSI box.

Telonics PC

The previous system incorporated a PC that managed the antennae control. This was replaced by the Telonics SCSI box in late 1999. The description is left here for reference.

The Telonics PC is an HP Vectra 486/66 that communicates with FOAM via the recorder cable and the MBARI network. A critical maintenance component of this system is the PC clock. The PC clock controls the timing of the antenna controller and needs to be maintained within one or two seconds of accuracy. This clock wanders over time and should be checked every week. Data flowing in from the antenna flows into the PC which then feeds SeaWiFS data to the Orbital Sciences Ground Processor for decoding and AVHRR data directly to FOAM.

Foam workstation

Foam is an HP UNIX workstation that serves as the main component of the MBARI satellite control system. Foam retrieves and maintains the satellite orbital elements, ingests the raw data from the SCSI box, generates and distributes data products, and stores raw data to tape. The main process of foam can be seen by looking at the two windows that should be running on the Foam monitor at all times. These windows, are labeled HRPTDI, and HRPTDP. The acronym HRPT stands for High Resolution Picture Transmission, while the last two letters describe tasks performed in each window. These tasks are explained below:

HRPTDI "Data Ingestion"

In the example below, the bottom line shows "off-line" . The "off-line" denotes that the system locked on to the satellite and received data. There is no evidence however that the data was backed up as planned The next line up shows "off-line off-line". Again the first "off-line" denotes that the system was successful in getting the data, and the second "off-line" denotes that the data was backed up to tape and is being stored. On the third line from the bottom, a pass is being processed. This is shown logically by "on-line (processing)". When the processing is complete, the screen will change to "off-line" or "off-line off-line" depending on the success of the operation. The top line indicates the next satellite to be received. "on Thurs., Feb. 19 at 18:45:34 (local)" Come back then and see it all run!

Example:

obv2 99049211055 1045 on Thurs., Feb., 19 at 18:45:34 (local)
noac 99049193323 1010 on-line (processing)
noae 99049151029 1127 off-line off-line (19)
noae 99049133018 1211 off-line on-line (19)

HRPTDP "Data Production"

The Data Production window, handles the tape backup, the conversion of raw telemetry to L0 data, and AVHRR data products. When this window fails, the passes in the HRPTDI window will not have the (19) at the end, nor will they write "off-line" to tape. Restarting this window requires restarting the whole process. The system will then automaticaly start to process all of the unprocessed data (those not marked with 19) and attempt to write the raw files to tape. Due to the fact that processing takes less time than tape writing, not all of the passes will be written to tape. Check back after an hour or so to write the unwriten passes to tape manualy.

Logins and ASAPs

Right clicking on the mouse produces a pop up menu that allows new logins and ASAP's. Logins are Root, GAE, HRPT, and FORCAST. Root is reserved for systems administrators, GAE and FORECAST are logins for the Orbital Imaging System 9000 software. HRPT is the preferred login used for system maintenance. Selecting ASAP brings up a second pop up list that will re-start the HRPTDI process described above. This was once useful because the system had the hobby of dropping the Data Ingestion window.

Contacts

Serge, Erich, Francisco, ect contact information available by clicking above.

Tape Back up system

The tape backup system is a 4mm tape installed in the FOAM chassy. These tapes are capable of holding about 3 days of SeaWiFS Data and hence must be changed regularly. Click here for instructions on how to maintain the tape system

Data Path

The links below will produce diagrams that follow the data path from raw satellite telemetry through to the final data products.

Seawifs Satellite to L1A

L2 to Final Data Products

AVHRR to Final Data Products

Foam File system

/foam
/satellite
   /avhrr
     /gif
        /lrg ; Large SST and Albedo AVHRR gifs
        /med ; Medium " "
        /sml ; Small " "
/usr
/wif
   /noac     ;HRPT Capture files
   /noae     ; " "
   /obv2     ; " "
   /seawifs
        /L0        ; Temp file directory. Mirrored on lepas: /seawifs/seawifs/archive. Physically on Tornado. Stores NO DATA
        /L0_done ; Temp file directory. Mirrored on lepas:/seawifs/seawifs/archive/. Physically on Tornado. Stores NO DATA
        /L1A     ;L1A files (Actually on Tornado" /vol/vol10/chfr/seawifs/seawifs)
        /L2        ;Empty
        /L3        ;Empty
        /demo    ;Empty

Lepas Workstation

The Lepas workstation is an SGI with dual 180Mhz processors. This is a dedicated computer that contains the SeaDas and IDL programs, the image processing scripts, and an extensive file structure for archiving the data.

/lepas
/seawifs
    /avhrr/gif
        /lrg               ; Large SST and Albedo AVHRR gifs
        /med             ; Medium " "
        /sml              ; Small " "
        /thumb          ; Thumbnails
    /idl                    ; IDL 5 and 5.1 files
    /idl.bak             ; IDL 5 backup files
    /seawifs
        /achive          ; This directory structrue is physicaly on Tornado, and mirroed on Foam: /wif/seawif/
        /data/L2      ; The GetL2, GetSST and runftp scripts plus 2 weeks of current data
        /l1agen       ; This is where the incoming Raw SeaWiFS LO and L1A data actualy resides
        /local_data
           /L1a          ; Empty
           /L2            ; Most of the SeaDas scripts called by GetL2 here, plus the years S*.sub.map files
           /L3            ; weekly cloro files
              /1998     ; 1998 weekly chloro files
              /monthly ; monthly chloro files
           /moorings ; erichs mooring data programs
              /file1      ; Mfiles and temp files to gather daily morring pixles
              /file2      ; file1 is the first pass of the day, file 2 is second
              /M1        ; temp files for M1 Mooring pixles
              /M2        ; " "
              /M3        ; " "
        /seadas          ; SeaDAS files
        /tmpGlobalImages ; Empty
        /updates         ; Empty

/bog
    /Carder_model   ; Carder Chl and CDOM model
    /eqpac          ; SeaWifs Data for Equpac moorings
    /G_S_model      ; Garver-Siegel Fortran Chl and CDOM model
    /GS_seawifs     ; Garver-Siegel Fortran optimized for IDL
    /pro_backup     ; Backup
    /prr            ; From Chrimson, old data
    /seawifs_local
        /L2         ;Full L2 files from nasa
        /L2_sub     ; 1998 L2 sub.map files
        /secret     ; Files and programs pertaining to secret cruises
    /Sst    ; SST's From AVHRR
        /Coastwatch ;
        /L2_sst     ;SST for MBARI sub-scene
        /north      ;SST northern portion of west coast
        /south      ;SST southern portion of west coast
        /southc     ; Cloud masks
    /wif    ;Old Chrimson data