Attitude Control Board PCBA

9-Axis Precision Attitude Determination — Quaternion MEKF with Tactical-Grade Gyroscope — DO-254 / IPC-6012 Class 3

Product Overview

The Attitude Control Board from Superb Automation is a precision-oriented PCBA dedicated to the determination and regulation of UAV orientation in three-dimensional space. While many flight controllers embed attitude estimation as one function among many, this specialized board devotes its entire computational and sensory resources to the singular task of maintaining accurate roll, pitch, and yaw angles. It employs a nine-axis sensor suite combining a tactical-grade MEMS gyroscope, a high-stability accelerometer, and a three-axis magnetometer, fused through an advanced multiplicative extended Kalman filter (MEKF) that maintains quaternion-based attitude representation to avoid gimbal-lock singularities. The hardware design follows DO-254 DAL C processes with full requirements traceability.

The board's 6-layer PCB layout separates the analog sensor chain from the digital processing domain via a continuous ground-plane split and ferrite-bead power isolation. A dedicated temperature-compensated crystal oscillator (TCXO) provides the precise timing reference needed for gyroscope integration, achieving a bias instability of less than 2 degrees per hour after factory calibration. The attitude solution is output at 1 kHz over a CAN bus interface, with raw sensor data also available at 8 kHz for external fusion systems. Onboard non-volatile memory stores factory calibration coefficients including axis misalignment, scale factor errors, and temperature compensation tables generated during Superb Automation's multi-point thermal calibration process spanning -40 °C to +85 °C.

Key Specifications

Calibration & Compensation

Each assembled attitude board undergoes a rigorous multi-point calibration on a precision three-axis rate table inside a thermal chamber. The calibration sequence characterizes gyroscope bias, scale factor, and axis misalignment at 11 temperature points from -40 °C to +85 °C. Accelerometer calibration includes cross-axis sensitivity and non-linearity correction. Magnetometer hard-iron and soft-iron compensation is performed with the board installed in its final mounting orientation relative to the UAV airframe. All calibration coefficients are stored in onboard EEPROM and automatically applied by the MEKF at runtime. A calibration certificate is provided with each unit, documenting measured performance against specification limits.

Test Strategy

Final acceptance testing verifies the complete attitude solution against an external fiber-optic gyroscope (FOG) reference on the rate table. Boards must achieve <0.5° RMS attitude error during aggressive multi-axis rotation profiles simulating flight maneuvers. CAN bus communication is verified across the full temperature range. The TCXO frequency is measured against a GPS-disciplined reference to confirm ±2 ppm stability. Power supply rejection ratio is tested by injecting ripple on the input rail and verifying <0.01° attitude disturbance.

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