Ground Station System Design and Implementation for Monitoring Rocket Telemetry

Ground station deployed at Payerne
Ground station deployed at the Payerne airfield

In the summer of 2018, the EPFL Rocket Team, which I am part of, will be attending the Intercollegiate Rocket Engineering Competition in the 10’000ft. COTS propulsion category.

The rocket is expected to reach an altitude of 1km above ground in less than 5 seconds. Therefore, we need a way of monitoring its performance automatically and in real-time. We distinguish three kinds of telemetry:

In-flight critical: data we absolutely need to monitor to assess the performance of the vehicle such as acceleration, speed and altitude.

Post-flight: additional data from the sensors such as orientation and temperature. The more data we collect, the better we can tune our flight simulator parameters.

Nice to have: the rest of the data that is not strictly required for the flight but can produce more accurate or nicer visualisations such as GPS coordinates throughout the flight.

Main features

Telemetry
  • Receive and fusion data coming from multiple, redundant channels (ex: 433MHz and 900MHz)
  • Handle data for multiple flying vehicles at the same time
  • Display critical in-flight telemetry values
  • Report radio link status in dBm and packets received per second
  • Dual screen, support for future extensions such as a live video feed
Visualisations
  • Interactive 2D plots of critical in-flight telemetry
  • Interactive 3D OpenGL visualisation of the flight trace, accurate digital elevation model of the terrain at the launch site (generated from SRTM data)
  • Support for splashdown trajectory prediction
data
  • Log data both at the byte and packet level
  • Replay logged data from previous flights

The two screenshots below respectively show the default view for critical telemetry as well as the advanced view for spatial visualisation of the rocket’s trajectory. Unfortunately, exact specifications regarding the design of the communication system and the code itself are not disclosed publicly for now.

Default view of critical telemetry
Critical telemetry plot during one of our test launches, at the 1670th second, parachute ejection caused a change in pressure which affected the computed altitude
Advanced spatial visualisation of trajectory and splashdown trajectory
Advanced spatial visualisation of trajectory and splashdown prediction, test setup in Kaltbrunn (ZH)
Part of the EPFL Team
Part of the team with the finished rocket