AMS02 Low Rate Data Links

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AMS-02 Low Rate Data Links

• X.Cai, MIT
• A.Lebedev, MIT

AMS TEM _at_ CAST, Beijing, January 2005
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Low Rate Data Link in AMS-02

• Is used to send commands from the ground to
  AMS-02
• Is used to send housekeeping data for AMS-02 to
  the ground
• Slow control data
• Critical health data

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Low Rate Data Link in AMS-02

• MIL-STD 1553-B standard is used
• NASA avionics interface is Bus Controller
• AMS-02 interface is Remote Terminal
• 1553 bus is double redundant
• Connection schemes are different for
• Launch pad
• STS (Shuttle)
• ISS (International Space Station)

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AMS-02 Telemetry Telecommand on STS/PAD
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Low Rate Data Link on Launch PAD

• To control and monitor the superconductive magnet
  just before the Shuttle launch the T0-cable is
  used
• NASA side Bus Controller software running on
  the PC computer
• AMS-02 side - AMS-02 side two JIM-AMSW/1553
  boards as two Remote Terminals
• Two fixed Remote Terminal addresses are used (4
  and 28)

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Low Rate Data Link on STS

• NASA side OIU as Bus Controller
• AMS-02 side two JIM-AMSW/1553 boards as two
  Remote Terminals
• Two fixed Remote Terminal addresses are used (4
  and 28)
• Two AMS-02 JIM-AMSW/1553 boards are connected
  through two stubs and couplers to 1553 bus
• The schematic connection diagram is presented on
  the next slide

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AMS-02 Telmetry and Telecommand on ISS
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Low Rate Data Link on ISS

• NASA side PLMDM as Bus Controller
• AMS-02 side four JIM-AMSW/1553 boards and JLIF
  board as one Remote Terminal
• Address is variable and is provided by jumpers in
  the connector on the S3 truss

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Low Rate Data Link on ISS

• AMS-02 is given one Remote Terminal address, but
  needs 4-time redundancy
• Four AMS-02 JIM-AMSW/1553 boards are connected to
  JLIF board which works as a multiplexer/demultiple
  xer
• JLIF board is connected through stub and coupler
  to 1553 bus
• In the beginning AMS-02 interfaces work as Bus
  Monitors waiting for the command to activate one
  out of its four interfaces to work as Remote
  Terminal
• Command to activate another interface to work as
  Remote Terminal may be then sent at any time
• The schematic connection diagram is presented on
  the next slide

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Low Rate Data Link Formats

• CCSDS packets are used
• Command always contains one AMS Data Block, but
  may occupy several CCSDS packets
• Housekeeping data is a stream of AMS Data Blocks
  packed into stream of CCSDS packets
• Critical Health Data have fixed position in CCSDS
  packet and could be easily retrieved

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1st Sub Address Block For AMS Command via OIU
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.45
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2nd Sub Address Block For AMS Command via OIU
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.46
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OIU/PDI HK 1st 1553 Sub Address Block(the
remaining nineteen 1553 blocks contain AMSBlock
data)
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.40
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OIU I/O Profile, recorded by Bus Monitor during
FIT test at KSC
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PLMDM Command 1st 1553 Sub Address Block
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.57
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PLMDM Command 2nd 1553 Sub Address Block
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.58
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ISS House-Keeping Data Format
From AMS document AMS02-CAT-ICD-R05m, Dec 10,
2004, p.55
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Payload MDM Local Bus PL-2 I/O Profile
From NASA document SSP 52050 Rev.D, June 8,2001,
p.A-3
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PLMDM I/O Profile, recorded by Bus Monitor during
FIT test at KSC
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Flight Commanding Conclusion Questions

• Commanding from China only, via Ground Station in
  Xian.
• Windows for 31 degree orbit typically 7min (9 m
  maximum) 6/day.
• (ps for Vladimir Altitude (BOL) of 500km orbit
  94.6 minutes)
• Uplink capability 2000 bits/sec
• This would require large rework of anticipated
  AMS flight procedures because AMS design
  considered almost always have command and
  telemetry (duty cycles greater than 70).
• Platform ALWAYS has priority for commanding
• At beginning, until AOCS stable, platform needs
  most of commanding capability.
• Once platform is stabilized, AMS requires the
  possibility for maximum commanding bandwidth and
  availability consistent with platform
  maintenance.
• AMS will receive commands over 1553B from OBDH
  uplink inject data
• Commanding frame is 64 Bytes (plus external RT
  addressing, ground formatting TBD)
• AMS will use one command from CAST point of view
  (fixed headers, variable contents), as foreseen
  with NASA.
• AMS will have 4 RT (4, 7, 13, 28) (one per JMDC,
  stuff all JIM-AMSW1553 with DDC chips).
• These are transformer coupled stubs.
• AMS needs time broadcast. Accuracy of time
  delivery to be understood.
• Dont forget about pad umbilical

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Flight Telemetry (eng. Data) Conclusion
Questions

• Eng. Data requested by OBDH from AMS over 1553
  continuously and downlinked. Received whenever
  over ground stations.
• Plan to also record complete stream (AMSplatform
  Eng Data) in DDR and playback/downlink via high
  rate system.
• Very prelimnary set of ground stations
• Guangzhou (22 deg ?)
• Las Palmas (28 deg ?), Of course Marco has no
  idea what is the name but he is thinking that it
  is really Maspalomas, Mike thinks it may be
  called this as well.
• Malindi (-3 deg)
• Coverage Orbits/day and duration TBD by CAST
  from STK database
• Expect again, few minutes for several orbits
  each day, each station
• Total of 2 hours/day tbc.
• Bandwidth 4096 bits/sec Priority for platform
• Platform requirements during nominal operations
  (after stabilization, etc) 1536bit/s
• Rest (2560bits/sec) for AMS.
• AMS data would be split into two streams high
  priority (e.g. 32Bytes) will be included as
  mission critical data and downlinked
  continuously.
• AMS low priority eng. data to be worked out.
• AMS High and low priority eng. data requested at
  different RT subaddresses
• AMS will inform which RT (4, 7 , 13, 28) to ask.
• NO CCSDS formatting for high priority data.
• Dont forget about pad umbilical
• Need to test response of OBDH BC to
  non-responding RT.