scholarly journals Analysis and Improvement of Attitude Output Accuracy in Rotation Inertial Navigation System

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Kui Li ◽  
Pengyu Gao ◽  
Lei Wang ◽  
Qian Zhang
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Angular Rate ◽  
Inertial Navigation ◽  
Dead Reckoning ◽  
Measurement Unit ◽  
Short Term ◽  
High Attitude ◽  
Navigation Accuracy ◽  
Accelerometer Biases

Inertial navigation system (INS) measures vehicle’s angular rate and acceleration by orthogonally mounted tri-axis gyroscopes and accelerometers and then calculates the vehicle’s real-time attitude, velocity, and position. Gyroscope drifts and accelerometer biases are the key factors that affect the navigation accuracy. Theoretical analysis and experimental results show that the influence of gyroscope drifts and accelerometer biases can be restrained greatly in rotation INS (RINS) by driving the inertial measurement unit (IMU) rotating regularly, thus improving navigation accuracy significantly. High accuracy in position and velocity should be matched with that in attitude theoretically since INS is based on dead reckoning. However, the marine and vehicle experiments show that short-term attitude output accuracy of RINS is even worse compared with that of nonrotation INS. The loss of attitude accuracy has serious impacts on many task systems where high attitude accuracy is required. This paper researched the principle of attitude output accuracy loss in RINS and then proposed a new attitude output accuracy improvement algorithm for RINS. Experiment results show that the proposed attitude compensation method can improve short-term pitch and roll output accuracy from 20~30 arc seconds to less than 5 arc seconds and azimuth output accuracy improved from 2~3 arc minutes to less than 0.5 arc minutes in RINS.

A self-calibration method for non-orthogonal angles of gimbals in rotational inertial navigation system based on fiber optic gyro

2017 ◽  
Vol 40 (13) ◽  
pp. 3665-3674 ◽  
Author(s):  
Zengjun Liu ◽  
Lei Wang ◽  
Wei Wang ◽  
Tianxiao Song
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Fiber Optic ◽  
Inertial Navigation ◽  
Calibration Method ◽  
Measurement Unit ◽  
Fiber Optic Gyroscope ◽  
Self Calibration ◽  
Photoelectric Encoder ◽  
Navigation Accuracy

Rotating modulation technique is a mature method that has been widely used in the rotational inertial navigation system (RINS). Tri-axis RINS has three gimbals, and the Inertial Measurement Unit can rotate along three directions to modulate the inertial devices’ errors, so that the navigation accuracy of the system can be greatly improved. However, the outputs of attitudes are easily affected by the non-orthogonal angles of gimbals, which should be accurately calibrated and compensated. In this paper, the effects of the non-orthogonal angles on the attitudes are discussed detailed and simulations based on Matlab are conducted to verify that firstly; then, a self-calibration method based on the outputs of the fiber optic gyroscope and photoelectric encoder is proposed. Experimental results in a real tri-axis RINS show that the attitude outputs accuracy are improved from 150” to less than 10”, which verify the practicability of the calibration method proposed in this paper.

scholarly journals High-speed train positioning method based on motion constraints suppressing INS error in tunnel

2021 ◽  
Vol 39 (3) ◽  
pp. 624-632
Author(s):  
Zhenqian Sun ◽  
Kanghua Tang ◽  
Meiping Wu ◽  
Yan Guo ◽  
Xueying Wang
Keyword(s):  
Navigation System ◽  
High Speed ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Measurement Unit ◽  
Mems Devices ◽  
High Speed Train ◽  
Motion Constraints ◽  
Navigation Accuracy ◽  
Constraints Model

When the high-speed train is running in tunnel, the global navigation satellite system (GNSS) signal is completely lost, and only relying on the inertial navigation system (INS) composed of micro electro mechanical system (MEMS) devices makes large navigation error. To solve this problem, a method considering the installation angles of micro inertial measurement unit (MIMU) relative to the train body for motion constraints aided inertial navigation system (CIAMC-INS) is proposed, which does not need extra sensors. This method first establishes motion constraints model based on the installation angles of MIMU; secondly, the effect of turning on the motion constraints model is analyzed, and the use condition of motion constraints is obtained; then, the installation angles of MIMU are estimated when GNSS signal is good and the use condition of motion constraints is met; finally, the estimated installation angles are applied to the motion constraints to suppress the error of pure inertial navigation system (P-INS) to improve the navigation accuracy in tunnel. Based on this method, high-speed train navigation tests are carried out both in the real tunnel environment and in the case of artificially disconnected GNSS signal. The experimental results show that the navigation accuracy of the train in the tunnel is significantly improved, which verifies the effectiveness of the method.

scholarly journals A System-Level Self-Calibration Method for Installation Errors in A Dual-Axis Rotational Inertial Navigation System

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 4005 ◽  
Author(s):  
Bai ◽  
Lai ◽  
Lyu ◽  
Xu ◽  
Liu ◽  
...  
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Angular Rate ◽  
Inertial Navigation ◽  
Calibration Method ◽  
System Level ◽  
Measurement Unit ◽  
Self Calibration ◽  
Rotation Axes ◽  
Rotation Scheme

In a dual-axis rotational inertial navigation system (RINS), there are two kinds of installation errors, nonorthogonal installation errors of inertial sensors, and installation errors between the inertial measurement unit (IMU) and rotation axes. Traditionally, these two errors are not considered simultaneously. Thus, they are calibrated separately by different estimation algorithms and rotation schemes. In this paper, a system-level self-calibration method for installation errors of a dual-axis RINS is proposed. Based on the Kalman filter, the measurement model is reestablished to ensure that all installation errors can be estimated together. First, the relationship between the initial attitude and subsequent attitude of IMU during rotation is used as a constraint to estimate nonorthogonal installation errors of accelerometers, and installation errors between the IMU and rotation axes. Then, the angular rate of the rotation mechanism is used as a reference to estimate nonorthogonal installation errors of the gyros. The rotation scheme of the IMU is designed to make all installation errors observable, and the observability of the system is analyzed based on the piecewise constant system method. Simulation and laboratory experiment results suggest that installation errors can be effectively estimated by the proposed method, thereby avoiding the complex separating process.

Error analysis and compensation for dual-axis inertial navigation system with horizontal rotation modulation

2018 ◽  
Vol 233 (1) ◽  
pp. 313-322 ◽  
Author(s):  
H Zhang ◽  
L Wang ◽  
TX Song ◽  
K Li
Keyword(s):  
Error Analysis ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Periodic Variation ◽  
Scale Factor ◽  
Measurement Unit ◽  
Actual System ◽  
Navigation Accuracy ◽  
The Impact

Rotational inertial navigation system can significantly improve the navigation accuracy by rotating the inertial measurement unit about gimbals periodically. The precise calibration for installation errors and scale factor errors in rotational inertial navigation system can contribute to better navigation performance further. Especially in application requiring excellent azimuth precision, the horizontal rotation modulation will be badly required to modulate the vertical sensors’ errors as periodic variation, which can make inhibiting effect on the navigation errors. However, it also enlarges the impact of specific errors, which contains gyro’s scale factor error and the installation errors of inertial components. To meet the requirement of navigation precision, this paper has made error analysis and established mathematical model for a proposed horizontal rotation modulation in dual-axis rotational inertial navigation system. The crucial error parameters can be calibrated based on the measurements of attitude and velocity output without additional equipment. The results of experiment performed in an actual system demonstrate that navigation accuracy has been improved significantly, fully illustrating the significance and necessity of the calibration for specific errors in the horizontal rotation modulation.

Screw Algorithm Optimized with Instantaneous Signals

2012 ◽  
Vol 229-231 ◽  
pp. 1671-1674
Author(s):  
Jian Feng Chen ◽  
Xi Yuan Chen ◽  
Xue Fen Zhu
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Angular Rate ◽  
Inertial Navigation ◽  
Strapdown Inertial Navigation System ◽  
Specific Force ◽  
Dual Quaternion ◽  
Screw Motion ◽  
Direct Component ◽  
Simulation Results

Recent dramatic progress in strapdown inertial navigation system (SINS) algorithm is the design of SINS principle based on screw algorithm, utilizing dual quaternion. In this paper, the screw algorithm consisting of angular rate and specific force is optimized under a special screw motion. The special screw motion is derived from classical screw motion and can be taken as a complicated sculling motion including classical coning motion. Subsequently, the coefficients in the multi-sample screw algorithms and the corresponding algorithm drifts are determined by minimizing the error on direct component. The simulation results of attitude and velocity errors agree with the optimization goals, except when the number of subinterval is greater than 2. An explanation of this phenomenon is delivered.

An Improved and Efficient Algorithm for SINS/GPS/Doppler Integrated Navigation Systems

2012 ◽  
Vol 245 ◽  
pp. 323-329 ◽  
Author(s):  
Muhammad Ushaq ◽  
Jian Cheng Fang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Sensor ◽  
Inertial Navigation ◽  
Measurement Unit ◽  
Navigation Systems ◽  
Integrated Navigation ◽  
Efficient Manner ◽  
Position Errors

Inertial navigation systems exhibit position errors that tend to grow with time in an unbounded mode. This degradation is due, in part, to errors in the initialization of the inertial measurement unit and inertial sensor imperfections such as accelerometer biases and gyroscope drifts. Mitigation to this growth and bounding the errors is to update the inertial navigation system periodically with external position (and/or velocity, attitude) fixes. The synergistic effect is obtained through external measurements updating the inertial navigation system using Kalman filter algorithm. It is a natural requirement that the inertial data and data from the external aids be combined in an optimal and efficient manner. In this paper an efficient method for integration of Strapdown Inertia Navigation System (SINS), Global Positioning System (GPS) and Doppler radar is presented using a centralized linear Kalman filter by treating vector measurements with uncorrelated errors as scalars. Two main advantages have been obtained with this improved scheme. First is the reduced computation time as the number of arithmetic computation required for processing a vector as successive scalar measurements is significantly less than the corresponding number of operations for vector measurement processing. Second advantage is the improved numerical accuracy as avoiding matrix inversion in the implementation of covariance equations improves the robustness of the covariance computations against round off errors.

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