Infrastructure & Software

Communication infrastructure description

Communication infrastructure consists of three main subsystems:

• Web Application - core application to store and manage all downlink and uplink data. Created by KRAKsat team. More information about the Web Application can be found in Alicja Kubera, "Web application for nanosatellite's data management" , Master Thesis, Jagielonian University, Cracow 2019, supervisor: Anna Sochocka.

• Mission Manager - desktop application connected to the Web Application API to allow an authenticated user to plan uplink commands in a convenient way. Created by SatRevolution.

• Ground Station Manager - desktop application on Ground Station Provider machine, providing planned uplink commands to the transceiver. Created by SatRevolution.

Infrastructure schema

Web Application - satellite position vizualization

Web Application - downlink files management

Mission Manager - planning commands software

Downlink software

Downlink can be demodulated from AFSK 1200 using software like Direwolf or SoundModem. Messages contain data from beacons, commands' responses and logs from flash memory in the form of ASCII text.

Decoder Module is part of the Web Application, created to automatically decode the received frames. Its main role is to transform all types of satellite communication data into a parameter-value form and push them to their proper destination - telemetry data into a time-series database and uplink responses into a relational one.

Decoding algorithm

1. Get a line of data.

2. Filter by callsign - SR9KRA.

3. Compare the first part of the line with:

   1. Beacon specification - if it matches:

      1. Mark as beacon.

      2. Decode data to parameter-value form.

      3. Push data into time-series database.

   2. Payload logs specification - if it matches:

      1. Mark as logs.

      2. Decode data from Base91.

      3. Split data into 6B lines of payload information.

      4. Decode data from binary form to proper variable types and parameter-value form.

      5. Push data into time-series database.

   3. Commands responses list - if it matches:

      1. Mark as uplink response.

      2. Decode data to parameter-value form.

      3. Push data into relational database database.

4. Display decoded data in Web Application.

Data visualization

All charts in the Web Application are based on satellite telemetry data. They display both decoded beacon frames, containing SR-NANO-BUS platform parameters, and data from payload logs.

Payload data visualisation

Beacon data visualization

Uplink software

Uplink can be created in the Mission Manager desktop application. After choosing the proper command and filling in its parameters, the operator can save the output to the file or, by default, send it to the Web Application with a chosen timestamp. Before every communication session, all prepared uplink data is displayed in the Ground Station Manager. There is a possibility to resend requests and create new commands in real-time.