On-Board Computer

Onboard Computer (OC) system is the chief source of intelligence in the satellite that exercises electronic control and utility operations, along with the other maintenance tasks during the course of operation of the satellite. It is a centralized, microcontroller based, fault-tolerant and interrupt driven system.

1. Antenna Deployment: On separation from the launch vehicle, OC is the second subsystem to be powered up after the power subsystem. It checks all the electronics on board and keeps all the communication loads off for 45 minutes after which it deploys the antenna.
2. Detumbling: Magnetorquers will be used to stabilize the satellite.
3. Orientation: Satellite needs to be oriented to obtain maximum thrust from solar sails. Reaction wheel will used to do for the same. Orientation is a continuous process. OC will continue orienting satellite for whole lifetime of satellite.
4. Solar Panel Deployment: Solar Panel would be deployed similar to Antenna Deployment.
5. Solar Sail Deployment: OC provides a frequency which would drive stepper motor thus deploying solar sail.
6. Data acquisition: Post solar sail deployment OC continues normal operation according to the mission plan. Periodically it collects data from on board electronics to check the status of respective subsystems. This data is logged in OC’s storage device and sent as Health Monitoring Data [HMD] after receiving request of HMD from administrator ground station.
7. Beacon Extraction: OC extracts beacon from acquired data and provides it to TNC for transmission
8. Command Handling: OC is responsible for responding to all commands uplinked from Ground Station.
9. Kill operation/Deorbit: It may also choose to kill the satellite in accordance with the kill procedure. In any form of communication, except beacon, ground station acts as the initiator of communication.
10. Load protection: Onboard computer acts as a redundant system to control load protection logic.

The system is required to control the initialization of the satellite. This involves, antenna deployment after separation from launch vehicle and solar panel deployment. Then it will commence normal operation.

During normal operation it is required to:
1. Gather health data from the sensors.
2. Store all gathered data in a log file with timestamp.
3. Send the periodic beacon signal and telemetry data through it.
4. Load protection.
5. Service other commands that are uplinked from the ground station.
6. Perform payload related tasks.

Software architecture

Software architecture

Current Team Lead:

Jatish Kharade (Final Year, Computer Engineering)

Email-ID: oc.csat@coep.ac.in

Team Members:

Runal Tembhurne (Final Year, Computer Engineering)

Avishkar Andhale (Third Year, Computer Engineering)

Rushikesh Deshmukhe (Third Year, Computer Engineering)

Aarya Chaumal (Third Year, Computer Engineering)

Purav Desai (Third Year, Computer Engineering)