Abstract: A system and method for determining attitude using triaxial micro electro-mechanical accelerometer-magnetometer sensors. The triaxial accelerometer-magnetometer sensors measure the triaxial components of the local gravity and magnetic field along three sensing axes of the sensors. The misalignment of the components due to nonorthogonal triaxial assembling of the sensors is estimated via performing three optical alignments and is further compensated in the sensing outputs. A micro-cube with three orthogonal coated mirrors is fixed on the circuit board of the system for implementing the optical alignments. The compensated sensing components are processed to figure out the attitude using Orientation Cosine Conversion of the local gravity and magnetic field. The computation for determining the attitude is based on the inverse tangent of the ratio of the processed components, which is more precise than the computation using the absolute values of the components.