A Four-Position Calibration Method of Inconsistent Angles between Units of TRUSINS

Calibration is very important to improve accuracy and reliability of inertial navigation system (INS). Especially for a novel triple rotary unit strap down inertial navigation system (TRUSINS), the inconsistent angles between three units can bring a cross-coupling error related to the measured angular velocity and the specific force. Therefore, it is necessary to precisely calibrate and compensate the inconsistent angles in a rapid and efficient way. This paper proposed a four-position calibration method based on a single-axis turntable. Making use of double sets of measurements along all three axes of body frame, this paper established an error model for the inconsistent angles in this novel TRUSINS. A four-position calibration experiment was designed and carried out. The results showed that the calibration accuracy of inconsistent angles between units meets the navigation requirements of TRUSINS.