MISRA-Compliant ADCS Software in C++

Obtain the MISRA C++:2008 standard (PDF available via purchase or institutional access). Read sections 0–5 to understand the rule categories: required rules (must never be violated), advisory rules (violated only with documented justification). Key flight software restrictions: no dynamic memory (no new/delete), no exceptions, no recursion, fixed-point math preferred over floating-point where possible.

Set up the toolchain: GCC/Clang for compilation, Cppcheck with the MISRA addon for static analysis, Google Test for unit testing, and gcov/lcov for code coverage measurement. Create a Makefile or CMake build system that runs static analysis as part of the build.

Write a Quaternion class that implements: multiplication, conjugate, normalization, rotation of a 3-vector, conversion to/from rotation matrix, and conversion to/from Euler angles. All operations must be MISRA-compliant: no exceptions, no dynamic allocation, no virtual functions in the core math path.

Use double for attitude math (not float — the precision matters). Write a full unit test suite covering: identity quaternion behavior, round-trip conversion tests, gimbal lock cases, and numerical normalization under repeated operations. Target 100% branch coverage on the Quaternion class before moving on.

The TRIAD algorithm computes the spacecraft attitude from two measured vectors (e.g., sun direction and magnetic field vector) compared to their expected values in the inertial frame. Implement triad(v1_body, v2_body, v1_inertial, v2_inertial) -> Quaternion.

Test with synthetic data: generate a known rotation, rotate reference vectors, apply TRIAD, and verify the recovered quaternion matches the true rotation. Test with noisy measurements (add Gaussian noise to body vectors) to characterize accuracy under realistic sensor conditions.

B-dot detumbling uses magnetorquers to damp spacecraft rotation after deployment, when the satellite may be tumbling at several degrees per second. The control law is: magnetic moment m = -k × dB/dt, where dB/dt is the time derivative of the magnetic field measured in the body frame and k is a gain constant.

Implement a B-dot controller that: reads body-frame magnetometer measurements, computes the numerical time derivative, computes the commanded magnetic moment, and clips to the maximum magnetorquer capability. Simulate the detumbling in Python (using scipy ODE solver) to validate the C++ control law produces stable damping.

For precise pointing, implement a PD attitude controller using reaction wheels. The control law: torque = -Kp × q_error_vector - Kd × omega_error, where q_error is the quaternion error between desired and current attitude and omega_error is the angular rate error.

Implement reaction wheel torque distribution using the pseudo-inverse of the wheel momentum matrix (pre-computed at compile time as a constant matrix). Test with a simulated slew maneuver: rotate from one pointing attitude to another and verify settling time and pointing accuracy meet CubeSat ADCS specifications (typically ±1° pointing accuracy).

Run Cppcheck with MISRA addon on all source files: cppcheck --enable=all --addon=misra.py src/. Work through every violation systematically. Document any advisory rule violations with justification comments in the code (MISRA allows violations with documented rationale).

Run gcov on the complete test suite and generate an HTML coverage report with lcov. Identify any uncovered branches and write additional tests until 100% branch coverage is achieved. Submit the final code with a coverage report and MISRA compliance summary — this is exactly what flight software deliverables look like.