Influence of gyro axis sequence configuration on the accuracy of alignment and navigation in a nested rotation inertial navigation system

Abstract

For the nested rotation inertial navigation system(NRINS) constructed by three ring fiber optic gyros nested with each other, it is analyzed that the main residual errors after rotation modulation are gyro angle random walk(ARW) and non-modulated gyro drift, It is pointed out that the different orientation of gyro sensitive axis leads to different equivalent ARW, and the non-modulated gyro drift caused by the nested installation of three ring gyros is also different. The generation mechanism of non-modulated drift in the embedded system and the general relationship with the axis sequence configuration are expounded. The equivalent ARW and non-modulated gyro drift in the inner frame rotation modulation mode and their influence on the alignment and navigation of the system are analyzed and deduced; Finally, taking the two typical applications of short-time navigation and long-time navigation as example, the influence of different gyro axis sequence configuration schemes on the navigation accuracy of the NRINS is verified through static navigation experiments, and the best axis sequence configuration scheme under the two applications is determined. By optimizing the gyro axis sequence configuration, the accuracy of navigation can be improved by about 2 times, which is of great significance. It has important reference value for further improving the accuracy of NRINS and maximizing the accuracy advantage of gyros in different applications.

MEMS strapdown inertial attitude measurement system using rotational modulation technology

“…When the IMU rotates relative to the z s axis, the rotation data of the earth and IMU are provided by the gyroscope. Eq (7) gives the theoretical output of the gyroscope in the IMU frame relative to the inertial frame, while Eq (8) describes the error…”

“…Therefore, this paper studies the rotation error modulation technology which only considers the inertial reference information. It only needs to move the IMU on the rotating platform according to the predetermined rotation scheme, and improve the attitude accuracy by compensating the navigation error caused by the inertial sensor bias in the entire rotation cycle [6][7][8]. This technology is applied to a MEMS-based rotating Strapdown Inertial Attitude Measurement System (SIAMS).…”