1. DTUsat Technical University of Denmark DTUsat onboard software architecture

2. DTUsat Technical University of Denmark Software elements One C program consisting of –The eCOS kernel –Packet router library –9 software modules: Platform manager Scheduler Housekeeping collector Telemetry manager Protocol (incl. Radio interface) Attitude Power Camera Tether

3. DTUsat Technical University of Denmark The module concept What is a module? –The basic idea of modules is to isolate the different parts of the system in order to simplify the system development and error handling Properties –Operates autonomously –Communicates with the rest of the system through the Packet Router using packets and the communication facilities of the Packet Router –Contains several parallel threads of execution –All modules share the same memory space

4. DTUsat Technical University of Denmark Packetformat

5. DTUsat Technical University of Denmark Telecommand packet flow ACDS Scheduler Protokol/Radio Packet router Incomming packet buffer Outgoing packet buffer Incomming packet buffer Outgoing packet buffer Incomming packet buffer 1 2 3 4 5 6

6. DTUsat Technical University of Denmark Telemetry packet flow ACDS TLM Protokol/Radio Packet router Outgoing packet buffer Incomming packet buffer Outgoing packet buffer Incomming packet buffer 1 2 3 5 6

7. DTUsat Technical University of Denmark About Redhat eCOS Small memory footprint (10-100 kb) Open source, royalty-free, license-free Highly customizable Real-time kernel including: –Interrupt handling –Exception handling –Thread support –Rich set of synchronization primitives –Timers, counters, and alarms

8. DTUsat Technical University of Denmark Developing modules In order to co-exist with other modules a module must comply to the rules regarding: –Naming conventions –Memory usage & allocation –Software watchdog –Receiving/sending packets Telecommands Telemetry Inter-module communication

9. DTUsat Technical University of Denmark Developing modules - Tools Module development and testing using the Linux synthetic target Common CVS (Concurrent Versions System) server –cvs.dtusat.dtu.dk System documentation (SDK) –www.dtusat.dtu.dk > software > architecture

10. DTUsat Technical University of Denmark Software projects Camera module –JPEG compression of images –Telecommands Attitude module –Implementing Matlab model in C –Telecommands Testing the onboard software –Scenarios –Developing methods for automated testing...

11. DTUsat Technical University of Denmark Q & A