Transcript 03 Use of EDS for Software Bus Adaptor

Use of EDS for S/W Bus
Adaptor
CCSDS SOIS 2013
Spring Meeting
Jonathan Wilmot NASA GSFC
1
Exemplar CFS Architecture
Spacecraft
Data
Recorder
Limit
Checker
Checksum
Scheduler
Stored
Commanding
CFDP File
Transfer
Data
Storage
File
Manager
Recorder
Manager
Instrument
1
Manager
Instrument
2
Manager
GNC Sensors
232
GPS
Altimeter
Onboard
Models
5 Hz
GPS IO
5 Hz
232
Alt IO
Software
Bus
Time
Services
Executive
Services
Event
Services
Health
&
Safety
House
keeping
Table
Services
Control
Law
50 Hz
422
LN200 IO
IMU
State
Determination
Inter-task Message Router (SW Bus)
1553 Bus
Controller
C&DH App
GN&C App
CFS App
cFE App
Time
Manager
Telemetry
Output
Cnd
Ingest
Space
Wire
Power
EDAC
Memory
Scrubber
S/C
Data
SBC
1553
Time HW
S-Comm
SpaceWire
Power hw
RAM & EEPROM
Housekeeping
Recorder
CFS Software Bus (SB)
• CFS components publish/subscribe to CCSDS packets
– Packets are either telecommand or telemetry
– Publishers have no knowledge of subscribers
•
One publisher to many subscribers is typical
–
•
•
Control log, Fault management, data storage, telemetry output
Send and forget
Subscribers can request packet meta data (Publisher appid, system, subsystem)
– Subscriptions are based on packet app id (2^11)
– Common CFS applications use a consistent set of app ids, but missions can
redefine them
– C structures are used in the software to extract packet data
•
CCSDS headers are not part of the C structures but via abstractions
• Ad-hoc tools are used to convert between C structures and ground
systems and tool databases
– Common definition parsed to generate packet definitions for other systems
• NASA working to establish CFS governance model and community
– Architecture, software, and tools commonality across many NASA missions
– Potential support for SOIS MTS compliance (Likely in the long term)
3
CFS Software Bus (SB)
• SB implements QOS only at the network interfaces
– SB API accepts QOS parameters and passes them down
• There is a Software Bus Network (SBN) component that
plugs in for each network type (Ethernet, TTEthernet,1553,
SpaceWire...)
– SBN is also used for interpartition (ARINC 653, PikeOS...), inter-core
messaging (Multi-core), and intra-processor
– SB is not aware that SBN(s) exists
– SBN will pass network to network through traffic
– SBN implements a peer to peer network
• No protocol master, connection mappings are kept local
• Peers can come and go at runtime
• All subscription requests are replicated (This can have scaling issues)
• Ground interfaces are through Command Ingest and
Telemetry Output plugins
• Not all components look at packet contents
– Data storage, telemetry output, both just filter and forward
4
Formats
•
CFS may move toward the DEM format which moves beyond the 2^11
appid (topic) limitation
–
Support for audio and video encapsulation
CCSDS format
MSB
bit
Data Exchange
message (DEM)
format
0
LSB
1
Version
2
3
4
5
6
7
Type ID
8
9
CRC
SecH
10
11
Origin Code
12
13
14
15
Operation Code
size
System ID
Rsvd
Content ID size
Content ID
Seconds MSW
Seconds LSW
Milliseconds
Source System
Rsvd
Source Subsystem
Counter
Data
5
EDS gets used in many places
Subnetwork services
Channelizations and
service type (packet…)
defined here
I/O
Schedule
EDS(s)
Data
Consumers
Device
SpaceWire
I/O
Device
Device
specific
driver(s)
Device
I/O
Schedule
device
device
Raw
Sensor
processing
RIU
device
1553
I/O
Device
Partition, core,
network…
Device
422
Device
Device
I/O
& Driver
Software
Bus
Network
(SBN)
Software
Bus
Network
(SBN)
6
Layered Approach:
Use of EDS in the System Stack
HW and/or
software
logic
SpaceWire
1553
Subnetwork
I/O
EDS
EDS
D1 FI
SpW
Access
D2
D1+D2
FI
SOIS
Access
1553
Access
D1
SpW
EDS
D1+D2
FI
RIU
1
1553
DVS
DAS
Sub PS
API
RS422
D3
Sensor
Processing
Software
Bus
Adaptor
SpW
EDS
DVS
DAS
Sub
MAS
Telemetry
Output
EDS
EDS
D1+D2
+D3 FI
D1+D2
+D3 FI
MTS
Access
TM/TC
Access
SW Bus
Spacecraft
Interface
(Data
Handling)
TM/TC
API
D3 FI
SpW
Access
EDS describes
interfaces of
Physical Devices
7
EDS describes
interfaces of SOIS
implementation API
EDS describes
interfaces of SW
Components
EDS describes
interfaces of
Spacecraft
Mission
Control
System
End to End
EDS
EDS
EDS
XTCE
database
Telemetr
y
monitors
Control Center
EDS
Software Bus
EDS
EDS
EDS
EDS
Reaction
Wheel
Star
Tracker
EDS
SOIS
Stack
RTU
driver
HW
EDS
File
Manage
r
CFDP File
Transfer
Mass
Storage
RTU
Meta data for file
contents?
1451
thermistor
HW
thermistor
HW
EDS
SOIS MTS
EDS
XTEDS
EDS
comm
1451
EDS
Command
EDS
Telemetr
y
comm