SRAD Flight Computer with State-Estimation EKF

For Launch Canada 2025, The Bishop Strachan Rocketry Team endeavoured on 3 SRAD primary components: airframe, avionics, and recovery. I led the avionics team of 12 members to design and build a custom flight computer for the rocket, with the goal of having reliable dual-deployment at apogee and main.

Research conducted for our flight computer consisted of both a hardware and software component.

Hardware-wise, we decided to go with a Teensy 4.1 microcontroller for its high processing power (600MHz) and large community support. We also incorporated an ICM-20948 9-DOF IMU for orientation sensing, a BMP388 barometric pressure sensor for altitude estimation, and some other minor circuit components such as MOSFETs, a 2-cell LiPo battery, magnetic switches and more. See the diagram below for the schematic.

Given my familiarity, the software component was a relatively simpler task. After some discussion with University of Waterloos avionics team, we decided to implement a Kalman Filter for sensor fusion and state estimation. I coded an Extended Kalman Filter (EKF) to estimate the rocket’s altitude and velocity based on the IMU and barometric pressure sensor data. The EKF was tuned to handle the high dynamics of a rocket launch, ensuring accurate state estimation throughout the flight.