Abstract: A new strapdown scheme is put forward for the Nongyroscopic Strapdown Inertial Navigation System (NGSINS), which is to make its Inertial Measurement Unit(IMU) rotate around an axis fixed in the vehicle body. With the proper configuration of nine accelerometers and an appropriate definition of Strapdown Matrix, this scheme can obtain high accuracy of angular velocity with no need for high precision sensors to measure the angular velocity of the IMU. The theoretical analysis and digital simulation show that to obtain the same accuracy of navigation, this scheme only needs much lower precision accelerometers, about one thousand times, than the traditional scheme of the NGSINS.

Key words: inert ial navigat ion, st rapdow n inert ial navigat ion, st rapdow n scheme, nongyro scop ic