A self-calibration method of inner lever arms for dual-axis rotation inertial navigation systems

Abstract

In an inertial navigation system (INS), it is generally assumed that three accelerometers in an inertial measurement unit measure the acceleration input at the same point in space. However, there are error vectors between the respective sensitive point of the three accelerometers and the theoretical measurement point, typically termed as inner lever arms (ILAs). In strapdown INS, the ILAs coupled with the carrier’s angular motion lead to a decline in navigation accuracy, while for dual-axis rotational INS (RINS), the ILAs coupled with the gimbals’ angular motion further introduce new navigation errors. Therefore, the calibration and compensation for the ILAs are important for enhancing the systemic reliability. In this paper, an ILA self-calibration method is proposed by leveraging the rotation gimbals of the RINS. To be able to obtain all the ILA parameters, we establish an error model by considering the ILAs, and design a reasonable rotation scheme to ensure all parameters observable. The simulations and experiments show that the proposed self-calibration method is able to accomplish the rapid and accurate estimation of all the ILAs and the velocity stage and slope errors are greatly corrected after compensation by the calibration results.

A rapid and high-accuracy rotation alignment method based on bidirectional process for dual-axis rotational inertial navigation system

“…In order to achieve the purpose of obtaining accurate misalignment angles in the dual-axis rotation alignment, it is necessary to construct a reasonable model of the ILAs and eliminate the errors introduced by it. The complete models of the ILAs are presented in [17,18]; however, these papers mainly researched the calibration methods aiming to obtain the IMU error parameters. For the alignment method, its purpose is the initial attitudes and its rapidity is equally important, hence we take into account the specific rotation scheme shown in figure 1 and simplify the model of the ILAs.…”

“…According to [17,18], the ILAs in dual-axis RINS are able to be illustrated as shown in figure 3, where Ox s y s z s represents the rotation frame. A X , A Y and A Z denote the corresponding accelerometer sensitive point.…”

A New Norm-Observed Calibration Method Based on Improved Differential Evolution Algorithm for SINS

“…Strapdown inertial navigation systems, once mounted on mobile carriers, should avoid repeated disassembly and keep high reliability for a long time in case of emergency usage. erefore, parameters downloaded inside the system need to be precisely identified and remain stable regardless of outside adverse circumstances, which brings a huge challenge for SINS calibration [1][2][3].…”

Modeling and Calibration for Dithering of MDRLG and Time-Delay of Accelerometer in SINS

“…Weng Jun included the non-synchronization of the accelerometer in Kalman’s state variables and perfected the calibration error model [ 15 ]. Literature [ 16 , 17 , 18 ] considered the size effect of the accelerometer and the accelerometer-gyro time asynchronous error. Literature [ 19 ] designed a 25-position rotation arrangement method, which additionally considered the quadratic error of the accelerometer and the error of the inner lever arm, and verified the feasibility of the calibration path.…”