Optimal configuration design of redundant strapdown inertial system with five axes

High reliability of navigation and guidance system directly determines the quality for solid launch vehicles to accomplish flight missions, while redundant inertial measurement technology is one of the main ways to increasing the system reliability. In this paper, taking a redundant configuration of strapdown inertial system with five axes (three on the spindles and two on the oblique axis) applied in solid launch vehicles as the research object and optimization of navigation performance index as objective function, nonlinear contradiction equations under optimal configuration were derived and the optimal imminent solutions were calculated by least square method, then finally the optimal configuration for redundant strapdown inertial system was obtained, which was also verified by simulation. The results demonstrate that there are 24 solutions for the optimal configuration for redundant strapdown inertial system with five axes (three on the spindles and two on the oblique axis), all of which have a navigation performance index of 1.4243 and when the fault happens in spindles, the configuration can reconstruct their information to ensure the accuracy and precision of navigation information with the navigation error within 5 times the error equivalence of gyro units.