Polar transfer alignment of shipborne SINS with a large misalignment angle

International Journal of Aerospace Engineering

et al. 2018

This paper deals with the problem of state estimation for the transfer alignment of airborne distributed position and orientation system (distributed POS). For a nonlinear system, especially with large initial attitude errors, the performance of linear estimation methods will degrade. In this paper, a nonlinear smoothing algorithm called the unscented particle smoother (UPS) is proposed and utilized in the off-line transfer alignment of airborne distributed POS. In this algorithm, the measurements are first processed by the forward unscented particle filter (UPF) and then a backward smoother is used to achieve the improved solution. The performance of this algorithm is compared with that of a similar smoother known as the unscented Rauch-Tung-Striebel smoother. The simulation results show that the UPS effectively improves the estimation accuracy and this work offers a new off-line transfer alignment approach of distributed POS for multiantenna synthetic aperture radar and other airborne earth observation tasks.

Section: Ups Design For Airborne Distributed Posmentioning

confidence: 99%

Unscented Particle Smoother and Its Application to Transfer Alignment of Airborne Distributed POS

Gong

Zheng

International Journal of Aerospace Engineering

et al. 2018

“…They are the i , e , b , g , G , n , b 0 and o frames. The i frame represents the inertial frame; e frame represents the Earth-centered Earth fixed frame; b frame represents the body frame of the UUV; g frame represents the geography frame; G frame represents the grid frame [17]; n frame represents the navigation frame; b 0 frame represents the initial body frame solidified to the inertial frame and o frame represents the body frame of OCTANS. These frames are common except the G frame and b 0 frame.…”

Section: Propaedeutic Conceptionmentioning

confidence: 99%

A Polar Initial Alignment Algorithm for Unmanned Underwater Vehicles

Wang

et al. 2017

Sensors

Self Cite

Due to its highly autonomy, the strapdown inertial navigation system (SINS) is widely used in unmanned underwater vehicles (UUV) navigation. Initial alignment is crucial because the initial alignment results will be used as the initial SINS value, which might affect the subsequent SINS results. Due to the rapid convergence of Earth meridians, there is a calculation overflow in conventional initial alignment algorithms, making conventional initial algorithms are invalid for polar UUV navigation. To overcome these problems, a polar initial alignment algorithm for UUV is proposed in this paper, which consists of coarse and fine alignment algorithms. Based on the principle of the conical slow drift of gravity, the coarse alignment algorithm is derived under the grid frame. By choosing the velocity and attitude as the measurement, the fine alignment with the Kalman filter (KF) is derived under the grid frame. Simulation and experiment are realized among polar, conventional and transversal initial alignment algorithms for polar UUV navigation. Results demonstrate that the proposed polar initial alignment algorithm can complete the initial alignment of UUV in the polar region rapidly and accurately.

“…The body frames of the master system and slave system are defined on the rigid body of the inertial measurement unit and are denoted by and , respectively. A detailed description of these coordinate frames is available in [21,24,25].…”

Section: Mathematical Modelingmentioning

confidence: 99%

“…The difference of the navigation results between the main node and subnode, such as attitude difference and velocity difference, is utilized to estimate the flexible deformation. This procedure is known as the transfer alignment [20,21].…”

Section: Introductionmentioning

confidence: 99%

Deformation Measuring Methods Based on Inertial Sensors for Airborne Distributed POS

Gong

Liu

International Journal of Aerospace Engineering

2017

This paper is focused on deformation measuring methods based on inertial sensors, which are used to achieve high accuracy motion parameters and the spatial distribution optimization of multiple slave systems in the airborne distributed Position and Orientation System or other purposes. In practical application, the installation difficulty, cost, and accuracy of measuring equipment are the key factors that need to be considered synthetically. Motivated by these, deformation measuring methods based on gyros and accelerometers are proposed, respectively, and compared with the traditional method based on the inertial measurement unit (IMU). The mathematical models of these proposed methods are built, and the detailed derivations of them are given. Based on the Kalman filtering estimation, simulation and semiphysical simulation based on vehicle experiment show that the method based on gyros can obtain a similar estimation accuracy to the method based on IMU, and the method based on accelerometers has an advantage in y-axis deformation estimation.