Parametric study of loosely coupled INS/GNSS integrity performance

Low-cost inertial sensors have been in the focus of ongoing research since they enable a low priced and low complex way to increase the robustness and reliability of navigation systems, especially GNSS. In this paper, we analyze a loosely coupled INS/GNSS including evaluation of the inertial error propagation and robustness of the corresponding navigation integrity concept with respect to the inertial system parameters. Moreover, we analyze the system integrity performance in terms of overall system protection level dependent on the inertial sensor error model. We discuss and compare the expected performance of using either typical high-end, middle-grad, low-cost or a network of redundant low-cost IMUs in terms of integrity and GNSS coasting time. We show that a network of four independent and identical distributed and orthogonally mounted low-cost sensors boosts the integrity performance significantly and even outperforms the one of a higher grade sensor. Additionally we discuss the trade-off between inertial networks and increased system complexity with respect to integrity performance in this paper.