Error Analysis of Space-Stable Inertial Navigation Systems

According to the application characteristics of the K-Rb-21Ne comagnetometer, a space-stable navigation mechanization is designed and the requirements of the comagnetometer prototype are presented. By analysing the error propagation rule of the space-stable Inertial Navigation System (INS), the three biases, the scale factor of the z-axis, and the misalignment of the x- and y-axis non-orthogonal with the z-axis, are confirmed to be the main error source. A numerical simulation of the mathematical model for each single error verified the theoretical analysis result of the system’s error propagation rule. Thus, numerical simulation based on the semi-physical data result proves the feasibility of the navigation scheme proposed in this paper.

Section: Error Analysis Of the Comagnetometer Space-stable Insmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Error Analysis of the K-Rb-21Ne Comagnetometer Space-Stable Inertial Navigation System

Cai

Yang

Quan

et al. 2018

“…Based on the n -frame error models of the pure-inertial navigation [ 8 , 26 , 28 ], variables involving

remain, while other relatively small quantities and the coupling between the vertical and the horizontal channels are neglected. Thus, the state equation of the kinematic errors in horizontal channels is simplified as

where

…”

Section: Traditional Horizontal Oscillation In Polar Regionsmentioning

confidence: 99%

Hybrid Transverse Polar Navigation for High-Precision and Long-Term INSs

Han

et al. 2018

Transverse navigation has been proposed to help inertial navigation systems (INSs) fill the gap of polar navigation ability. However, as the transverse system does not have the ability of navigate globally, a complicated switch between the transverse and the traditional algorithms is necessary when the system moves across the polar circles. To maintain the inner continuity and consistency of the core algorithm, a hybrid transverse polar navigation is proposed in this research based on a combination of Earth-fixed-frame mechanization and transverse-frame outputs. Furthermore, a thorough analysis of kinematic error characteristics, proper damping technology and corresponding long-term contributions of main error sources is conducted for the high-precision INSs. According to the analytical expressions of the long-term navigation errors in polar areas, the 24-h period symmetrical oscillation with a slowly divergent amplitude dominates the transverse horizontal position errors, and the first-order drift dominates the transverse azimuth error, which results from the g0 gyro drift coefficients that occur in corresponding directions. Simulations are conducted to validate the theoretical analysis and the deduced analytical expressions. The results show that the proposed hybrid transverse navigation can ensure the same accuracy and oscillation characteristics in polar areas as the traditional algorithm in low and mid latitude regions.

“…Inertial navigation systems (INSs) tend to be the first choice for marine navigation because they are able to output motion parameters completely, autonomously, and continuously [ 1 , 2 , 3 ]. In order to fulfill the requirement for long-term and high-precision marine navigation, it is essential for INSs to employ high-precision inertial instruments.…”

Section: Introductionmentioning

confidence: 99%

A Three-Stage Accelerometer Self-Calibration Technique for Space-Stable Inertial Navigation Systems

Han

et al. 2018

As a specific force sensor, the tri-axis accelerometer is one of the core instruments in an inertial navigation system (INS). During navigation, its measurement error directly induces constant or alternating navigation errors of the same order of magnitude. Moreover, it also affects the estimation accuracy of gyro drift coefficients during the initial alignment and calibration, which will indirectly result in navigation errors accumulating over time. Calibration can effectively improve measurement accuracy of the accelerometer. Device-level calibration can identify all of the parameters in the error model, and the system-level calibration can accurately estimate part of these parameters. Combining the advantages of both the methods and making full use of the precise angulation of the space-stabilized platform, this paper proposes a three-stage accelerometer self-calibration technique that can be implemented directly in the space-stable INS. The device-level calibration is divided into two steps considering the large amount of parameters. The first step is coarse calibration, which identifies parameters except for the nonlinear terms, and the second step is fine calibration, which not only identifies the nonlinear parameters, but also improves the accuracy of the parameters identified in the first step. The follow-on system-level calibration is carried out on part of the parameters using specific force error and attitude error to further improve the calibration accuracy. Simulation result shows that by using the proposed three-stage calibration technique in the space-stable INS, the estimation accuracy of accelerometer error can reach 1×10−6 normalg order of magnitude. Experiment results show that after the three-stage calibration, the accuracy of latitude, longitude, and attitude angles has increased by over 45% and the accuracy of velocity has increased by over 22% during navigation.