This project was created as part of a Challenge Project for a job interview. It allows for telemetry from a simulated ground station to be processed, stored and available for display graphically. Definitely one of the more interesting challenge projects I've been given and one that I really enjoyed.
The project has been configured to be run using Docker Compose. To run it, follow the steps below:
- Open an appropriate command line client and clone the Git repository to your local machine
- Edit the env_vars.env file and replace the default entries for INFLUXDB_PASSWORD and INFLUXDB_TOKEN
- Type docker-compose up --build from the root directory
- Open a web browser and navigate to http:\localhost:8086 then log in using the username and password from env_vars.env
- Click the boards option of the side-bar, select Satellite Telemetry then select 5s from the Refresh rate drop-down.
The project is comprised of three distinct services:
- Telemetry Generator
- Telemetry Receiver
- Telemetry Visualiser
The Telemetry Generator is a TCP Server that transmits telemetry on two satellites using two different encoding methods. Each satellite transmits its telemetry at a rate of approximately 2 Hz. The telemetry transmitted consists of a timestamp, an ID indicating the type of telemetry and a value. From observation, each satellite only transmits telemetry for a single, unique ID. The two encoding methods used are UTF-8 String and LE Binary. Each satellite's data is transmited on a different port with the default ports in use being 8000 for the UTF-8 String and 8001 for the LE Binary.
The Telemetry Generator can be found within the Telemetry folder and consists of a single linux binary and an associated Dockerfile. The docker-compose file in the root project directory will run up the generator using the default ports of 8000 and 8001.
The Telemetry Receiver handles the receiving of telemetry data from the Telemetry Generator, decoding it and then transmitting it onwards for storage within a database. The project has been written in C# using .NET Core 3.1 and is designed to be run within a container as a service.
The Telemetry Receiver can be configured to receive either UTF-8 String Encoding or LE Binary Encoding. The receiver encoding to use is set by argument passed to the container at runtime. To configure for UTF-8 String the container should be started with a command string for LE Binary the container should be started with the command binary. Both the port and the hostname on which the receiver will listen can be set via the TELEMETRY_HOST and TELEMETRY_PORT environmental variables.
For example, to run up the Telemetry Receiver for UTF-8 String encoding as an independent container type:
docker run -d -p 8000:8000 --env-file env_vars oc/telemetryreceiver string
For LE Binary type:
docker run -d -p 8001:8001 --env-file env_vars oc/telemetryreceiver binary
The project has been designed to use Influx OSS DB as the storage and visualisation engine. This integration is achieved through the cInfluxDriver class within the Decoder. The connection details for Influx can be manipulated via environmental variable and the required variables can be found in the env_vars.env file in the root of the project. This includes the following settings:
- INFLUXDB_HOST = Host name to use for connecting to the Influx OSS DB instance
- INFLUXDB_PORT = Port for the Influx OSS DB instance
- INFLUXDB_ORG = Organisation to create and use within Influx
- INFLUXDB_BUCKET = Data bucket to use for storing telemetry
- INFLUXDB_USER = User name to create and use within Influx
- INFLUXDB_PASSWORD = Password for the username
- INFLUXDB_TOKEN = Authorisation Token for use in Influx
The password and token must both be set in order for the DB to boot.
The Telemetry Visualiser handles the storage and display of the telemetry data that's received, decoded and transmitted onwards by a Telemetry Receiver. It provides a thin wrapper around the Influx OSS DB official Docker image (v2.0.2). The wrapper handles the initialisation and application of the appropriate template to ensure the most efficient display of telemetry within the solution.
To view the telemetry, open a web browser and go to http:\\localhost:8086 and then login using the credentials supplied in the env_vars.env file. Once logged in, click Boards and then Satellite Telemetry to view a display of the data being transmitted from the Telemetry Generator. By default, the dashboard will be paused so be sure to select an appropriate refresh rate (Suggested is 5s) from the top right options to view a live display of data from the satellites.