goes-r brown bag series goes-r series flight data system william (bill) anderson goes-r flight...
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GOES-R Brown Bag Series
GOES-R Series Flight Data System
William (Bill) Anderson
GOES-R Flight Project
Flight Data System Lead
301-286-7569
October 29, 2014 Slide 1
GOES-R Flight Data System
Agenda
• What’s new/different from a data management perspective. In The Beginning Where We Are Today
• Technology developed for GOES-R series spacecraft. EDAC On Board Intelligence SpaceWire Reliable Data Delivery
• GOES-R data sources and sinks. C&DH Architecture
October 29, 2014 Slide 2
GOES-R What’s New/Different – In The Begining
• Earlier GOES spacecraft utilized deterministic Time Division Multiplexing (TDM).– On board data was “commutated” into a structure known as a
frame.
– When a frame is received on the ground, a “decommutation” process is applied to recover individual measurands.
– Bit slips and bit errors can cause data loss.
October 29, 2014 Slide 3
GOES-R What’s New/Different – Where We Are Today
• The following is an excerpt from the Wikipedia entry on GOES-R: GOES-R will mark the first major technological advances in geostationary observations
since 1994. Compared to the current GOES system, the advanced instruments and data
processing will provide: Three times more spectral information Four times greater spatial resolution Five times faster coverage Real-time mapping of total lightning activity Increased thunderstorm and tornado warning lead time Improved hurricane track and intensity forecasts Improved monitoring of solar x-ray flux Improved monitoring of solar flares and coronal mass ejections Improved geomagnetic storm forecasting
• These improved capabilities presented a unique set of challenges for the design of the GOES-R flight data system.
October 29, 2014 Slide 4
GOES-R What’s New/Different – Where We Are Today
• GOES-R is a packet telemetry and packet telecommand system.
• Packets are non-deterministic data structures. System buffering and through put allow packets to
be sent when ready with minimal wait times.• Packet transmission components are independent
and isolated from the data in the packet.• Everything required to recover measurands is
contained in the packet header.• Packet types and contents can be modified on orbit.
October 29, 2014 Slide 5
GOES-R What’s New/Different – Where We Are Today
• GOES-R complies with Consultative Committee for Space Data Systems (CCSDS) telemetry and telecommand recommendations.
http://public.ccsds.org/default.aspx• From CCSDS Web site:
“eleven member agencies (world wide), twenty-eight observer agencies, and over 140 industrial associates”
“--- actively developing recommendations for data and information systems standards to promote interoperability and cross support among cooperating space agencies”
• Building GOES-R to data standards helps reduce costs. COTS products available – don’t have to reinvent
the wheel
October 29, 2014 Slide 6
GOES-R What’s New/Different – Where We Are Today
October 29, 2014 Slide 7
• Source Packet format - a frame is a frame is a frame ---
• The APID is used to route and process the data contained in the packet
• Used for both telemetry and command• The GOES-R high level packet format is defined in the
GIRD• Lower level packet formats are defined in the instrument
and spacecraft CMD/TLM handbooks.
APPLICATIONPROCESS
ID
11 bits
GOES-R Technology– Error Detection and Correction
• Improved data reliability – multiple layers. GOES-R uses multiple Error Detection and
Correction (EDAC) through out the data system to have highly reliable data delivery to the ground.
Packets can contain EDAC codes to reduce errors and data loss.
Transmission systems utilize protocols to improve reliability.
Space-to-ground links use coding to improve margins and reduce data loss.
October 29, 2014 Slide 8
GOES-R Technology – On Board Intellegence
• GOES-R utilizes a RAD750 32 bit computer with Wind River’s VxWorks operating system (MacIntosh in the sky).
• The instruments are also intelligent.• Flight software is written in C with some minor
exceptions. ABI - RAD750 with VxWorks SUVI - RAD750 with VxWorks SEISS - Atmel TSC695FL EXIS - RTAX2000 Actel Core8051 GLM - BAE ASIC Embedded Microcontroller (EMC)
October 29, 2014 Slide 9
GOES-R Technology – SpaceWire
• SpaceWire (ECSS-E50-12A) is a standard for high-speed links and networks for use onboard spacecraft, easing the interconnection of: sensors mass-memories processing units, and downlink telemetry sub-systems.
http://www.spacewire.esa.int/content/Home/HomeIntro.php
• SpW is versatile, simple, and can support data rates into the hundreds of Mbps.
• SpW supports worm hole routing.
October 29, 2014 Slide 10
GOES-R Technology – SpaceWire
• NASA and GOES-R participated in the development of the BAE SpW Application Specific Integrated Circuit (ASIC).
October 29, 2014 Slide 11
OCB Connection Medium
EMC
64
OCB Master
64
OCB Slave
SRAM
64
OCB Slave
PID’s
MISC
32
OCB Slave
Existing
New/Modified
UART
UART
32
OCB Slave
MCTL
Memory I/F
64
OCB Slave
SRAM
64
OCB Slave
JTAG
32
OCB Master
JTAG Slave (JTAG)
Clocks/Reset
CAT
32
PLL
OCB Slave
64
OCB Master
32
OCB Slav
e
64
RIF
OCB Master
64
OCB Master
32
OCB Slav
e
64
RIF
OCB Master
External I/F
64 64
OCB Master
OCB Slave
EXTIF 1
External I/F
64 64
OCB Master
OCB Slave
EXTIF 2
Spacewire Router and Links
Spacewire I/F
4
FIF
O
FIF
O
FIF
O
FIF
O
GOES-R Technology – SpaceWire
• GOES-R indirectly participated in the development of the Aeroflex 4 port SpW router ASIC.
October 29, 2014 Slide 12
GOES-R Technology – SpaceWire
• GOES-R developed an in house proof of concept SpaceWire system.
• This system consisted of 6 Windows based work stations and custom SpW test cards BAE ASIC test card:
October 29, 2014 Slide 13
GOES-R Technology – SpaceWire
• GOES-R developed an in house proof of concept SpaceWire system. FPGA based SpW Test Set (SWTS) card:
October 29, 2014 Slide 14
GOES-R Technology – Reliable Data Delivery
• SpW (physical layer) provides a limited error management capability.
• GOES-R Flight System Engineering levied requirements for higher level error management for the SpW links. In response, the GOES-R Reliable Data Delivery
Protocol (GRDDP) was developed by the C&DH team.
GRDDP was presented to and accepted by the SpW working group (PID 238).
• All instrument to spacecraft communications requires use of the GRDDP.
October 29, 2014 Slide 15
GOES-R Technology – Reliable Data Delivery
• GRDDP was designed to have minimum impact on flight computers. GRDDP sample software is ~700 lines of C code. GRDDP sample code has been provided to a
number The GOES-R GRDDP sample code was provided to all GOES-R contractors.
GRDDP sample code has been provided to a number of non NASA/NOAA programs.
• SEISS and EXIS have implemented the GRDDP in FPGAs.
October 29, 2014 Slide 16
DestinationSLA
1 byte
ProtocolID
1 byte
SourceSLA
1 byte
UserDefined
4 bits
Packet Type
4 bits
PacketLengthMSB
1 byte
PacketLength
LSB1 byte
ChnnelNumber
1 byte
SequenceNumber
1 byte
Packet Control
Application Data
0 to 65535 bytes
CRC
1 byte
0 or moreDestinationAddresses
Payload EOP
Protocol Packet
GOES-R Data Sources and Sinks – C&DH Architecture
• C&DH Block Diagram
October 29, 2014 Slide 17
GOES-R Data Sources and Sinks – C&DH Architecture
• C&DH Block Diagram - OBC
October 29, 2014 Slide 18
RAD750 hosts Flight Software8 SpaceWire Nodes provides Interfaces to InstrumentsMIL-STD-1553B Bus Controller to Spacecraft ComponentsCCSDS Formatting and LDPC encoding to Raw Data Link for Instrument Data1PPS Generation and DistributionIMU InterfaceGPSR Interface Maintains Spacecraft ClockInternally Redundant
GOES-R Data Sources and Sinks – C&DH Architecture
• C&DH Block Diagram - CTP
October 29, 2014 Slide 19
Interface to CDAS and ORTT&C Comm EquipmentCommand receptive on all Communication UplinksPerforms CCSDS Validation of all uplinked commands including COP-1 protocolsInterface to the Command Decryption Unit AssemblyCCSDS Formatting and Reed Solomon encoding to CDAS and ORTT&C EquipmentExecution of Hardware Commands-32V Relay Drive Commands+28V Pulse and Level CommandsMonitors Health and Controls the state of the OBCInternally Redundant