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Design and Implementation of Spacecraft Avionics
Software Architecture based on Spacecraft Onboard
Interface Services and Packet Utilization Standard
Beijing Institute of Spacecraft System Engineering,
China Academy of Space Technology (CAST)
Xiongwen He
10/11/2015
Catalogue
1
Introduction
2
Software Architecture Design
3
Implementation and Verification
4
Conclusion
1. Introduction
Currently the characteristics of integration of functions have occurred in
spacecraft, especially in Chinese spacecraft. Traditional spacecraft
functions such as Telemetry and Telecommand, data handling and so on,
have been integrated into avionics system, which also realizes the
autonomous function, including information management, resource
management, operation management and safety management.
1. Introduction
The benefit of integration is the uniform and optimized configuration of
resources, the reduction of power consumption and weight, the
improvement of autonomous ability and the standardization of interface
and products. However, the coupling of each subsystem is also increased
and the hardware and software are becoming more complicated.
How to make the avionics system software adapt the different hardware
interface, protocols and the change of user requirements, and to increase
the reusability of software, is the problem that is to be solved during the
avionics system software architecture design.
1. Introduction
SOIS is focused on the research of onboard information exchange and the
onboard interface of each subsystem and equipment. The layered
architecture defined by CCSDS can shield the upper layer from the change
of hardware and provide a set of standard services to be used by user
applications. The concept of SOIS can be referenced and adopted in the
design of avionics system software architecture.
ECSS published the Telemetry and Telecommand Packet Utilization
Standard (PUS) , which defined 16 services and standardized the
application layer interface between ground and spacecraft, provided
support for the top-level application of avionics system.
1. Introduction
With SOIS and PUS integrated, a new avionics system software
architecture has been designed to solve the problem mentioned above, thus
increase the software reuse, shorten the software development cycle and
increase the efficiency of software development.
Catalogue
1
Introduction
2
Software Architecture Design
3
Implementation and Verification
4
Conclusion
2. Software Architecture Design
2.1 Principles
-
decompose and simplify the complex problem into several layers
through layering
-
standardize the interface of operating system
-
define the framework of device drivers
-
establish a uniform information transfer mechanism
-
define the standardized components and their interfaces
2. Software Architecture Design
2.2 Software Architecture Design
Based on the principles, we presented a software architecture which
includes operating system layer, middleware layer and application layer.
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
PUS Service Components
Application
Support
Layer
Middleware
Layer
System
Configu
-ration
Manage
-ment
Transfer
Layer
Subnetwork
Layer
MTS
Compone
nt
DDPS
Compon
ent
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
Extension
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(1)Operating System Layer
-
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
provide a uniform API
PUS Service Components
-
Application
Support
Layer
any Operating System that supports
Middleware
Layer
this API can be used
-
System
Configu
-ration
Manage
-ment
Transfer
Layer
Subnetwork
Layer
include real-time kernel, BSP, device
MTS
Compone
nt
new devices supported by add new
drivers
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
drivers and basic function library
-
DDPS
Compon
ent
Extension
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(2)Middleware Layer
-
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
a common service platform
PUS Service Components
-
Application
Support
Layer
integrate SOIS and PUS
Middleware
Layer
-
has standard program interface and
Transfer
Layer
Subnetwork
Layer
protocols
-
System
Configu
-ration
Manage
-ment
MTS
Compone
nt
DDPS
Compon
ent
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
is divided into three layers
Extension
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(2)Middleware Layer
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
Subnetwork Layer
PUS Service Components
-
Application
Support
Layer
include onboard subnet components
Middleware
Layer
and space subnet components
-
service,
Transfer
Layer
Subnetwork
Layer
support packet service, memory
access
System
Configu
-ration
Manage
-ment
MTS
Compone
nt
-
support TC protocol, AOS protocol
-
isolate the influence of the change of
hardware interface and protocols
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
synchronization
service, link convergence
DDPS
Compon
ent
Extension
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(2)Middleware Layer
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
Transfer Layer
PUS Service Components
-
include
Space
packet
Application
Support
Layer
protocol
Middleware
Layer
component
-
System
Configu
-ration
Manage
-ment
Transfer
Layer
Subnetwork
Layer
space packet protocol is enhanced with
MTS
Compone
nt
-
syncretize the space link and onboard
link using packets
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
address information added in the
secondary header
DDPS
Compon
ent
Extension
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(2)Middleware Layer
Application
Layer
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
Application Support Layer
PUS Service Components
-
Application
Support
Layer
support SOIS MTS , DAS , DVS ,
Middleware
Layer
DDPS,TAS,FPSS services
-
support PUS services
-
allow Service Extension
System
Configu
-ration
Manage
-ment
Transfer
Layer
Subnetwork
Layer
MTS
Compone
nt
DDPS
Compon
ent
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
Extension
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.2 Software Architecture Design
(3)Application Layer
-
contains
most
of
Application
Layer
the
Telemetry
Telecommand
Time
Management
Housekeeping
Management
Thermal
Management
Power
Management
Payload
Management
Middleware API
common
PUS Service Components
Application
Support
Layer
functions of avionics system
Middleware
Layer
-
combine the different basic services of
middleware
layer
to
System
Configu
-ration
Manage
-ment
Transfer
Layer
Subnetwork
Layer
implement
MTS
Compone
nt
using tasks or processes with OS
support
DAS
Compo
nent
Space Packet
Component
DVS
Compone
nt
TAS
Compon
ent
FPSS
Component
Extension
Onboard Subnet Components
functions
-
DDPS
Compon
ent
Extension
Space Subnet Components
Operating System API
Operating
System
Layer
Real-time
Kernel
BSP
Device
Drivers
Basic
Function
Library
CPU
ROM
RAM
Timer
1553B
Inner
Bus
UART
Extension
Interface
Hardware
Watchdog
Extension
2. Software Architecture Design
2.3 Interface Design
(1)Interface of each layer
-
Operating system layer interface: includes task management interface,
interrupt management interface, memory management interface,
semaphore management interface, timer management interface, IO
interface, user support library interface and so on.
-
Subnetwork layer interface: includes packet service interface,
memory access service interface, synchronization service interface,
TC interface, AOS interface and so on.
-
Transfer Layer interface: includes space packet interface and so on.
-
Application
Support
Layer:
interface,DAS interface,…
includes
PUS
interface,
MTS
2. Software Architecture Design
2.3 Interface Design
(2) Interface of Component
The outside interface contains the following types.
-
-
the provided interface, including:
-
initialization interface
-
functional interface
-
configuration interface
the needed interface: called by this component, which is realized
through configuration.
Catalogue
1
Introduction
2
Software Architecture Design
3
Implementation and Verification
4
Conclusion
3. Implementation and Verification
The architecture is implemented and verified based on avionics system
prototype , including SMU and SDIU.
-
device drivers and BSP developed
-
28 software components of the middleware developed
-
coded more than 40000 lines
-
programmed by C language
-
implementation scheme for all components using method of software
engineering
3. Implementation and Verification
-
components assembled and executed on both SMU and SDIU
-
configuration of the software components and the operating system
are pretty much the same
-
main differences are:
-
1553B convergence component :BC mode on SMU and RT mode
on SDIU
-
Some PUS components not included in SDIU
-
Some configurations different (route table, device access table,
device data pool configuration,etc.)
3. Implementation and Verification
-
verified on tornado vxSim platform
-
result shows that the change of hardware interface and protocols can
be adapted by the design of the architecture
-
different requirements can be realized by the combination of service
components
-
reusability of the software is well proved
-
to be tested and verified on the hardware in the future
Catalogue
1
Introduction
2
Software Architecture Design
3
Implementation and Verification
4
Conclusion
4. Conclusion
-
Aiming at the trend of the function integration, synthesis and fast
software development on spacecraft avionics system, the avionics
system software architecture designed can adapt to the change of
hardware interface, protocol and user requirements through layered
design and the integration of several standard services and protocols.
Thus the development of application software will be more flexible
and efficient which will benefit the reuse of avionics system software
so that the spacecraft life cycle will be shortened and the cost will be
saved.
4. Conclusion
-
There are still some other problems that still need to be concerned on
the architecture, such as how to support the partition management of
operating system, how to realize the visualized assemble of software
components and the visualized simulation of information flow, etc.
Thank you!
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