Simulation Study for FOG Strapdown Inertial Navigation Nonlinear Alignment Based on SVD-Cubature Kalman Filter

With the rapid development in technology of Fiber Optical Gyroscope (FOG), the Platform Inertial Navigation System has been replaced by FOG Strapdown Inertial Navigation Sysem (FOG SINS) gradually. In this paper, an Euler angle nonlinear error model is introduced for large attitude misalignment of FOG SINS. Then, based on matrix singular value decomposition and cubature rule for Gaussian-weighted integrals, a new Cubature Kalman Filter (CKF) is presented. The initial alignment of FOG SINS based on the nonlinear error model and Cubature points updated SVD-CKF, adopting the velocity matching method just estimate and compensate misalignment angles. And compared the nonlinear alignment with the traditional coarse alignment and compass alignment, this method can satisfy the requirement of the initial alignment of SINS.