An innovative high-precision gyroscope-free strapdown inertial navigation scheme

Abstract Compared to traditional strapdown inertial navigation system (SINS), gyroscope-free SINS has significant advantages such as low cost, small size and power consumption, and high reliability. It is a new type of SINS that has emerged in recent years. To satisfy the application requirements for low-cost, miniaturized, and highly reliable inertial navigation, and to improve the accuracy of gyroscope-free inertial navigation, an innovative high-precision gyroscope-free strapdown inertial navigation scheme is proposed in this paper. Under the non-center-of-mass installation configuration mode of accelerometers in gyroscope-free SINS, the intrinsic coupling relationship between the outputs of accelerometers and the specific force at the carrier’s center of mass (COM) is first revealed. The optimal accelerometer configuration is then designed by minimizing the output error variance of the accelerometers, thereby improving the calculation accuracy of the specific force at the carrier’s COM. In addition, by utilizing the orthogonality constraint relationship between the tangential and centripetal accelerations in the outputs of accelerometers installed at non-center-of-mass positions, the acceleration orthogonality constraint model is constructed and introduced into the estimation of the carrier’s angular velocity, thereby enhancing the degree of observability of the angular velocity and further improving its estimation accuracy. Finally, the results of the vehicle-mounted experiment show that, compared with the traditional gyroscope-free strapdown inertial navigation scheme, the proposed innovative scheme achieves higher precision in positioning, velocity measurement, and attitude determination. Specifically, the standard deviations of position, velocity, and attitude errors are reduced by more than 63.63%, 60.44%, and 60.02%, respectively, enabling high-precision gyroscope-free inertial navigation.