Structure and Configuration

How pFS is structured and configured

High Level Structure

pFS is structured into two parts: core and submodules. core is representative of a system while submodules tailor to individual hardware. An example of a submodule would be aprs.py. aprs.py is the submodule that pertains to and only to the APRS radio. The methods within aprs.py would pertain only to interfacing with the APRS radio so messages can be sent and received through the physical APRS radio and be processed within the pFS application. An example of a core function would be power monitoring. In flight, it is the responsibility of core to constantly read the current power levels of the CUBESAT and react accordingly. This functionality uses submodules to read the report current energy levels from the power delivery system(EPS). Power monitoring is not specific to any one submodule and affects the pFS application as a whole, therefore core is responsible for monitoring power levels.

More on core here.

More on submodules here. List of actual submodulebelow.

Configuration

• config/config_default.yml and config/config_custom.yml

  • The config_*.yml files provide configuration information specific to each submodule and `core`

    • e.g. serial ports for each submodule(/dev/ttyUSB0 for APRS)

    • e.g. telemetry dump intervals

    • e.g. structuring of submodules for startup(core)

  • config_custom.yml(if present) is given priority over config_default.yml

    • config_custom.yml is gitignored and is specific to each individual developer, but config_default.yml provides the configuration specific to the environment on flight-pia

  • Here is an excerpt of config/config_default.yml for the aprs submodule

  aprs:
      depends_on:
          - telemetry
      serial_port: /dev/ttyUSB0
      telem_timeout: 70
      message_spacing: 1

  • The parent key aprs denotes that the following values are specific to aprsa

    • The depends_on specifies a list of other submodules on which the parent key(aprs) needs to be able to access in flight

    • The other values(serial_port ,telem_timeout ,message_spacing) are constants specific to aprs

Submodules

Here is a list of all the submodulesused in pFS

Everything listed here has a corresponding Python file in pFS

1. antenna deployer

   1. Handles the deployment of the ISIS Antenna

2. aprs

   1. Handles the receiving and sending of messages through the APRS radio

3. command_ingest

   1. Handles the parsing and execution of command messages

4. eps

   1. Handles the interfacing between pFS and the Clyde Space EPS(power management)

5. iridium

   1. Handles the receiving and sending of messages through the Iridium radio

6. telemetry

   1. Handles the collection and formatting of telemetry data for the satellite as a whole