Error analysis for SINS with different IMU rotation scheme

Influence on Strapdown Inertial Navigation System (SINS) error characteristics for different IMU (inertial measurement unit) rotation schemes was analyzed theoretically.It´s indicated that, in single-axial and single-directed rotation scheme the gyro´s bias on rotational axis was not modulated, but a equivalent bias calculate by scale-factor error multiplying rotating velocity was introduced in rotational axis,which limit the position precision of the SINS. But in dual-axial and single-directed rotation scheme, both gyro´s bias and aforementioned equivalent bias were modulated, whenas another equivalent bias caused by coupling of the scale-factor error and the movement of vehicle were introduced and this bias also limited the position precision. The analysis in theory was proved by simulation.