Onboard Computer (OBC) - CalgaryToSpace/CTS-SAT-1-Wiki GitHub Wiki
Onboard Computer (OBC)
The Onboard Computer (OBC) is a custom PCB, design in-house by CalgaryToSpace members.
The following are the GitHub Repos for the OBC:
- https://github.com/CalgaryToSpace/CTS-SAT-1-OBC-PCB
- https://github.com/CalgaryToSpace/CTS-SAT-1-OBC-Firmware
Subteams That Affect It
These are the subsystems & their relevant subteams that affect the performance of the Onboard Computer:
Subteams That Are Affected By It
These are the subsystems & their relevant subteams that are affected by the performance of the Onboard Computer:
Mission Requirements/Constraints
| OBC | Requirement Description | Rationale | Verification Methods (Inspection, Analysis, Demonstration, Testing) | Verification Description | AIT Phase | Supports | Supported By | Notes | Automated Software Testing |
|---|---|---|---|---|---|---|---|---|---|
| OBC-1 | The OBC shall interface with the MPI. | Payload operated through ground commands relayed by OBC. | Testing | Try all commands, echo from MPI to confirm | A | MOP-1, MOP-2, MOP-4 | Power | Y | |
| OBC-2 | The OBC shall program the MPI with updated flight software. | This is necessary to allow any firmware updates to the MPI. | Demonstration | ||||||
| B | Maybe (Unclear) | ||||||||
| OBC-3 | The OBC shall verify that flight software uploaded from the ground is not corrupted. | This will ensure that the correct code is uploaded and that it has not been corrupted. | B | MOP-1 through MOP-8 | What might go wrong without CRC? | Y | |||
| OBC-4 | The OBC shall have sufficient storage for software, redundant software and data. | Required to operate payloads and collect science data. | A | MOP-1 to MOP-8, MOP-10 | Y | ||||
| OBC-5 | The OBC shall interface with the ADCS | The mission requires control of the satellite's altitude from the ground. Manual adjustments will be made via commands to be received & relayed by the OBC. | Testing | Try all needed commands to see if they are successfully received. | A | MOP-1 to MOP-3, MOP-6 to MOP-8 | Power | Y | |
| OBC-6 | The OBC shall interface with the GPS | MPI data stored on the OBC needs to be stamped with time and position data acquired by the GPS | A | MOP-3 | Power | Y | |||
| OBC-7 | The OBC shall interface with the Communication subsystem. | The OBC will transmit stored data and relay telecommands from the groundstation to complete operations. | Testing | Try all needed commands to see if they are successfully received by communications microcontroller. | A | MOP-1, MOP-2, MOP-4 to MOP-7, MOP-10 | Power | Y | |
| OBC-8 | The OBC shall interface with the deployment mechanism for the DCLB. | Observing properties of the boom is a primary purpose of the mission. A method for manual control is needed. | Testing | Try commands to see if motors is successfully actuated. | A | MOP-5, MOP-6, MOP-10 | Power | Y | |
| OBC-9 | The OBC shall interface with the camera. | The camera is the means by which the boom will be observed. A method of manual control is needed. | A | MOP-6 | Power | ||||
| OBC-10 | The OBC shall interface with the EPS. | The OBC will toggle power to the distribution system so all other modules can be operated. | Testing | Try commands to see if power to subsystems is toggled successfully. | A | MOP-1 to MOP-8, MOP-10 | Y | ||
| OBC-11 | The OBC shall decrypt signals received through the antenna | This is necessary to receive telecommands and transmit data | Testing | Show that signals can be successfully sent and received. | B | MOP-8 | Comms | Y (Simulate the signals in a buffer to test decryption) | |
| OBC-12 | The OBC shall encrypt signals transmitted through the antennae | B | MOP-4, MOP-6, MOP-7 | ||||||
| OBC-13 | The OBC shall isolate and correct errors caused by radiation events | The CubeSat will be continually exposed to radiation, which can cause data corruption or crashing of the computer | Testing | Simulate state of corrupted data and show that OBC successfully reboots. | MOP-1 through MOP-8 | Maybe(depends if we can simulate data corruption) | |||
| OBC-14 | The OBC shall receive telecommands from the ground. | The state and operation of each subsystem is determined by the software mode | B | MOP-1 to MOP-8, MOP-10 | Comms | ||||
| OBC-15 | The OBC shall stamp MPI data with location and time data from the GPS | B | MOP-3 | GPS | |||||
| OBC-16 | The OBC shall have at least three independent RF inhibits to prohibit inadvertent RF transmission | ||||||||
| OBC-17 | The OBC shall have at least three independent inhibits to prohibit the inadvertent release of any deployable structures. | ||||||||
| OBC-18 | The OBC shall include an RBF pin, which cuts all power to the satellite once it is inserted into the satellite. | ||||||||
| OBC-19 | The RBF pin and all CubeSat umbilical connectors shall be within the designated access port locations if available on the CubeSat's dispenser | ||||||||
| OBC-20 | RTC frequencies shall be less than 320 kHz. |