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action | 4 months ago | |
container | 4 months ago | |
contrib/sgp4 | 6 months ago | |
controller | 7 months ago | |
coordinates | 7 months ago | |
datalinklayer | 6 months ago | |
datapool | 7 months ago | |
defaultcfg | 4 months ago | |
devicehandlers | 4 months ago | |
events | 4 months ago | |
fdir | 7 months ago | |
globalfunctions | 6 months ago | |
health | 4 months ago | |
internalError | 7 months ago | |
ipc | 5 months ago | |
logo | 3 months ago | |
memory | 5 months ago | |
modes | 5 months ago | |
monitoring | 6 months ago | |
objectmanager | 5 months ago | |
osal | 4 months ago | |
parameters | 6 months ago | |
power | 7 months ago | |
pus | 5 months ago | |
returnvalues | 4 months ago | |
rmap | 7 months ago | |
serialize | 6 months ago | |
serviceinterface | 7 months ago | |
storagemanager | 5 months ago | |
subsystem | 6 months ago | |
tasks | 5 months ago | |
tcdistribution | 5 months ago | |
thermal | 7 months ago | |
timemanager | 4 months ago | |
tmstorage | 6 months ago | |
tmtcpacket | 4 months ago | |
tmtcservices | 5 months ago | |
unittest | 4 months ago | |
.gitignore | 3 years ago | |
.gitmodules | 5 months ago | |
FSFWVersion.h | 4 months ago | |
LICENSE | 3 years ago | |
NOTICE | 3 months ago | |
README.md | 3 months ago | |
fsfw.mk | 5 months ago |
The Flight Software Framework is a C++ Object Oriented Framework for unmanned, automated systems like Satellites.
The initial version of the Flight Software Framework was developed during the Flying Laptop Project by the University of Stuttgart in cooperation with Airbus Defence and Space GmbH.
The framework is designed for systems, which communicate with external devices, perform control loops, receive telecommands and send telemetry, and need to maintain a high level of availability. Therefore, a mode and health system provides control over the states of the software and the controlled devices. In addition, a simple mechanism of event based fault detection, isolation and recovery is implemented as well.
The recommended hardware is a microprocessor with more than 2 MB of RAM and 1 MB of non-volatile Memory. For reference, current Applications use a Cobham Gaisler UT699 (LEON3FT), a ISISPACE IOBC or a Zynq-7020 SoC.
The general structure is driven by the usage of interfaces provided by objects. The FSFW uses C++11 as baseline. The intention behind this is that this C++ Standard should be widely available, even with older compilers. The FSFW uses dynamic allocation during the initialization but provides static containers during runtime. This simplifies the instantiation of objects and allows the usage of some standard containers. Dynamic Allocation after initialization is discouraged and different solutions are provided in the FSFW to achieve that. The fsfw uses Run-time type information. Exceptions are not allowed.
Functions should return a defined ReturnValue_t to signal to the caller that something is gone wrong. Returnvalues must be unique. For this the function HasReturnvaluesIF::makeReturnCode or the Macro MAKE_RETURN can be used. The CLASS_ID is a unique id for that type of object. See returnvalues/FwClassIds.
The FSFW provides operation system abstraction layers for Linux, FreeRTOS and RTEMS. A independent OSAL called "host" is currently not finished. This aims to be running on windows as well. The OSAL provides periodic tasks, message queues, clocks and Semaphores as well as Mutexes.
Clock:
ObjectManager (must be created):
template <typename T> T* ObjectManagerIF::get( object_id_t id )
Event Manager:
namespace fsfwconfig {
//! Configure the allocated pool sizes for the event manager.
static constexpr size_t FSFW_EVENTMGMR_MATCHTREE_NODES = 240;
static constexpr size_t FSFW_EVENTMGMT_EVENTIDMATCHERS = 120;
static constexpr size_t FSFW_EVENTMGMR_RANGEMATCHERS = 120;
}
Health Table:
Stores
Tasks
There are two different types of tasks:
Some parts of the framework use a static routing address for communication. An example setup of ids can be found in the example config in "defaultcft/fsfwconfig/objects/Factory::setStaticFrameworkObjectIds()".
Events are tied to objects. EventIds can be generated by calling the Macro MAKE_EVENT. This works analog to the returnvalues. Every object that needs own EventIds has to get a unique SUBSYSTEM_ID. Every SystemObject can call triggerEvent from the parent class. Therefore, event messages contain the specific EventId and the objectId of the object that has triggered.
Components communicate mostly over Message through Queues. Those queues are created by calling the singleton QueueFactory::instance()->create().
The external communication with the mission control system is mostly up to the user implementation. The FSFW provides PUS Services which can be used to but don't need to be used. The services can be seen as a conversion from a TC to a message based communication and back.
If the communication is based on CCSDS Frames and Space Packets, several classes can be used to distributed the packets to the corresponding services. Those can be found in tcdistribution. If Space Packets are used, a timestamper must be created. An example can be found in the timemanager folder, this uses CCSDSTime::CDS_short.
DeviceHandlers are a core component of the FSFW. The idea is, to have a software counterpart of every physical device to provide a simple mode, health and commanding interface. By separating the underlying Communication Interface with DeviceCommunicationIF, a DH can be tested on different hardware. The DH has mechanisms to monitor the communication with the physical device which allow for FDIR reaction. A standard FDIR component for the DH will be created automatically but can be overwritten by the user.
The two interfaces HasModesIF and HasHealthIF provide access for commanding and monitoring of components. On-board Mode Management is implement in hierarchy system. DeviceHandlers and Controllers are the lowest part of the hierarchy. The next layer are Assemblies. Those assemblies act as a component which handle redundancies of handlers. Assemblies share a common core with the next level which are the Subsystems.
Those Assemblies are intended to act as auto-generated components from a database which describes the subsystem modes. The definitions contain transition and target tables which contain the DH, Assembly and Controller Modes to be commanded. Transition tables contain as many steps as needed to reach the mode from any other mode, e.g. a switch into any higher AOCS mode might first turn on the sensors, than the actuators and the controller as last component. The target table is used to describe the state that is checked continuously by the subsystem. All of this allows System Modes to be generated as Subsystem object as well from the same database. This System contains list of subsystem modes in the transition and target tables. Therefore, it allows a modular system to create system modes and easy commanding of those, because only the highest components must be commanded.
The health state represents if the component is able to perform its tasks. This can be used to signal the system to avoid using this component instead of a redundant one. The on-board FDIR uses the health state for isolation and recovery.
A example config can be found in defaultcfg/fsfwconfig.
Unit Tests are provided in the unittest folder. Those use the catch2 framework but do not include catch2 itself. See README.md in the unittest Folder.