Xiang Xu

Xiang Xu
Nanjing University of Science and Technology | NJUST · School of Automation

Ph.D

About

56
Publications
5,611
Reads
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801
Citations
Additional affiliations
February 2022 - present
Nanjing University of Science and Technology
Position
  • Associate Professor
August 2021 - January 2022
Soochow University
Position
  • Professor (Associate)
August 2018 - July 2021
Soochow University
Position
  • Lecturer
Description
  • Inertial navigation, initial alignment, MEMS Sensor, high accurate micro accelerometer

Publications

Publications (56)
Article
Full-text available
With the wide use of intelligent mobile terminals, inertial measurement unit (IMU) made by micro-electromechanical system (MEMS) has become an important part of their positioning systems. MEMS IMU has advantages of low cost, low power consumption and small size. However, the scale factor error, nonorthogonality error, and bias affect the measuremen...
Article
Full-text available
With the progress of micro electromechanical system (MEMS) technology, the performance of MEMS inertial measurement unit (IMU) composed of gyroscopes and accelerometers has been improved. Among the inertial sensors, MEMS triaxial gyroscope plays an important role in attitude estimation, navigation and positioning of intelligent mobile terminals suc...
Article
In this paper, the in-motion polar alignment method for SINS/GPS integration is proposed. Firstly, to address the defects of the fast convergence of the longitude with the navigational mechanization, the unified navigation mechanization is used to construct the vector observations for the in-motion alignment method. Secondly, the initial velocity e...
Article
Water current velocity aided strapdown inertial navigation system (SINS)/ Doppler velocity logs (DVL) integration system has shown great performance in mid water areas. Though the velocity error will converge once DVL bottom track (DVL-BT) is obtained, the position error accumulated during mid water period should be further optimized employing the...
Article
In this paper, an improved in-motion alignment method for SINS/GPS integration is proposed. The alignment errors, which are caused by the maneuvering of the vehicle and the accumulated errors of inertial sensor errors, are suppressed. Firstly, the traditional in-motion alignment method for SINS/GPS integration is reviewed, and the existing problems...
Article
Full-text available
Aiming at the problem that the USBL installation error is difficult to accurately calibrate in the complex underwater environment. In this paper, based on smooth variable structure and unscented Kalman filter, a novel USBL installation error calibration algorithm is proposed. Firstly, the nonlinear system model of USBL installation error based on t...
Article
Full-text available
In order to solve the problem of SINS/DVL/USBL system interference in complex underwater environment. An asynchronous sequential robust filter method is proposed in this paper. The original output azimuth, slant range and altitude of the ultra-short baseline as the measurement information, a compact combination model is established. The problem of...
Article
The strapdown inertial navigation system (SINS) and Doppler velocity log (DVL) are the major positioning system for underwater vehicles. The initial alignment process is the first working stage of SINS/DVL integration. Currently, the initial alignment method for SINS/DVL integration is imperfect. The major problems can be summarized in two aspects....
Article
Combining a global navigation satellite system (GNSS) and microelectromechanical technology-based inertial system (MINS) has become essential in land vehicle navigation systems. In an urban environment, the error of position output by GNSS receiver increases because of the blocking and reflection of the signal by buildings, which affects the positi...
Article
Layer based water current aided strapdown inertial navigation system (SINS)/ Doppler velocity logs (DVL) integration system has provided continuously navigation solution for the underwater vehicles’ diving and rising periods in deep water areas. However, as the water current varies both vertically and horizontally, difficulty arises when the vehicl...
Article
The measurement error of the inertial measurement unit (IMU) seriously affects the navigation accuracy of the strap-down inertial navigation system (SINS) in polar region. In order to improve navigation precision, a self-compensation method of the single-axis rotation modulation transverse SINS based on virtual sphere model is proposed in this pape...
Article
Foot-mounted pedestrian navigation system (PNS) is a common solution to pedestrian navigation using micro-electro mechanical system (MEMS) inertial sensors. The inherent problems of inertial navigation system (INS) by the traditional algorithm, such as the accumulated errors and the lack of observation of heading and altitude information, have beco...
Article
In this article, an in-motion coarse alignment method in the polar region is proposed. Different from the traditional coarse alignment method, the vector observation is constructed with the grid frame. Thus, the calculated singularity in the polar region, which is easy to see in the navigational frame, is suppressed. Considering the GPS measurement...
Article
Initial alignment is an indispensable technique for strapdown inertial navigation system (SINS) because the navigation accuracy of SINS depends on the performance of the initial alignment method. However, considering the rapid convergence of meridians and the small horizontal component of the Earth’s rotation in the polar region, traditional statio...
Article
Strapdown inertial navigation system (SINS)/ Doppler velocity log (DVL) tightly coupled (TC) fusion is a popular scheme as it offers increased robustness compared to other approaches. In TC, DVL beam velocities are separately integrated with SINS in the navigation filter. To enhance the performance of SINS/DVL TC integration system in situations of...
Article
Full-text available
In view of the large thermal drift of microelectromechanical system (MEMS) triaxial accelerometer and the high cost of traditional calibration schemes, this article proposes a low-cost and efficient thermal drift calibration scheme combining the parameter-correction method and the proposed least squares method based on the nine-parameter model. In...
Article
In this paper, a novel robust initial alignment method for the strapdown inertial navigation system (SINS) and global positioning system (GPS) integrated system is proposed to eliminate the outliers containing in the outputs of GPS. There are two innovations in the proposed method. First, the traditional quaternion Kalman filter method is often use...
Article
SINS/GPS integrated navigation system has been used widely in many application situations. In the SINS/GPS integrated navigation system, the initial alignment process is carried out to determine the initial attitude of the vehicle. Based on the previous works, the position loci method is a robust initial alignment method. The outliers, which are co...
Article
Initial alignment is of vital importance to the inertial navigation system, and the in-motion initial alignment is a critical stage for the moving vehicles. In this paper, an in-motion alignment method for SINS/GPS integration is investigated. Using the velocity, which is obtained from GPS, the observation and the reference vectors are constructed....
Article
Full-text available
Up/down static and the six-position least squares calibration methods are commonly used in research conducted on adjustment of the micro-electromechanical systems (MEMS) accelerometer scale factor (or sensitivity). When applying these methods, it is difficult to adjust the accelerometer measuring axis parallel to the gravity direction, causing an e...
Article
This paper addresses the underwater acoustical localization problem by using the time-difference-of-arrival (TDOA) and bearing-angle-of-arrival (BAOA) measurements. For the underwater acoustic equipment, such as the ultra-short baseline system (USBL), whose bearing measurements are different from the traditional angle-of-arrival (AOA) model, a clos...
Article
Full-text available
Due to the principle error caused by the Earth’s sphere model in transverse polar navigation, the ellipsoid model is usually used for transverse transformation. In order to avoid the complex transverse transformation of the ellipsoid model, a virtual sphere model, which can simplify the transformation of the ellipsoid model, is constructed in this...
Article
With the increase in the application of micro-electromechanical system (MEMS) accelerometers, their accurate calibration is increasingly essential to reduce the application error. Aiming at the high accuracy calibration requirements of scale factor, bias, and nonorthogonalities, we propose a novel calibration method to obtain highly accurate parame...
Article
Full-text available
As a widely used inertial device, a MEMS triaxial accelerometer has zero-bias error, nonorthogonal error, and scale-factor error due to technical defects. Raw readings without calibration might seriously affect the accuracy of inertial navigation system. Therefore, it is necessary to conduct calibration processing before using a MEMS triaxial accel...
Article
The initial alignment process is of vital importance to the strapdown inertial navigation system (SINS), and SINS is consisting of the inertial sensors. In this paper, the aiding velocity of Doppler Velocity Log (DVL) is used to implement the in-motion alignment process. However, the measurements of DVL are easy to corrupt by the outliers, and the...
Article
To mitigate the Doppler velocity logs (DVL) measurement errors in inertial navigation system (INS)/DVL integrated navigation system under dynamic environment, a simple and precise correction method is proposed. First, the general DVL velocity measurement error model under various dynamics is explored. Then, the corresponding correction scheme is pr...
Article
For underwater Strapdown Inertial Navigation System (SINS)/Doppler Velocity Log (DVL) integration system, there are intervals between DVL’s transmitting and receiving epochs, which introduces velocity errors when the attitude dynamic occurs. To accelerate the coarse alignment process for SINS/DVL with attitude dynamics, an improved in-motion coarse...
Article
Misalignment angle will result in a considerable error for the integration of Doppler Velocity Log (DVL) and of Strapdown Inertial Navigation System (SINS). In this paper, a robust initial alignment method for SINS/DVL is proposed to solve a practical applicable issue, which is that the outputs of DVL are often corrupted by the outliers. Firstly, t...
Article
Full-text available
This study analyses the transfer path of electrical feed-through noise in the electromechanical amplitude modulation detection circuit of a micro-electro-mechanical system vibrating gyroscope. By considering the feed-through, circuit and mechanical thermal noises, a new noise model in the force-to-rebalance closed-loop detection is constructed, and...
Preprint
Full-text available
The MEMS magnetometer determines the orientation for the MEMS inertial system. Because of the large noise of the MEMS magnetometer and the interference of soft and hard iron outside, the measurement error of the MEMS magnetometer is large. To reduce the effects of the random noises, the MEMS magnetometer arrays are designed in this paper. In our de...
Preprint
Full-text available
The MEMS magnetometer determines the orientation for the MEMS inertial system. Because of the large noise of the MEMS magnetometer and the interference of soft and hard iron outside, the measurement error of the MEMS magnetometer is large. To reduce the effects of the random noises, the MEMS magnetometer arrays are designed in this paper. In our de...
Preprint
Full-text available
The MEMS magnetometer determines the orientation for the MEMS inertial system. Because of the large noise of the MEMS magnetometer and the interference of soft and hard iron outside, the measurement error of the MEMS magnetometer is large. To reduce the effects of the random noises, the MEMS magnetometer arrays are designed in this paper. In our de...
Article
In this paper, a fast robust in-motion alignment method is proposed for the strapdown inertial navigation system (SINS) with DVL aided. The proposed method is divided into two procedures, which are coarse alignment procedure and fine alignment procedure. In the coarse alignment procedure, an apparent velocity modeling method is investigated. Buildi...
Preprint
Misalignment angle will result in a considerable error for the integration of Doppler Velocity Log (DVL) and of Strapdown Inertial Navigation System (SINS). In this paper, a robust initial alignment method for SINS/DVL is proposed to solve a practical applicable issue, which is that the outputs of DVL are often corrupted by the outliers. Firstly, t...
Article
To improve the efficiency of the calibration process and enhance the adaptability of the calibration method, an interacting multiple model and unscented Kalman filter (IMM-UKF) aided strapdown inertial navigation system (SINS) / Ultra-Short Base Line (USBL) calibration solution is proposed for the common calibration procedure, where only one transp...
Article
Full-text available
This study presents a new real-time calibration algorithm for three-axis magnetometers by combining the recursive least square (RLS) estimation and maximum likelihood (ML) estimation methods. Magnetometers are widely employed to determine the heading information by sensing the magnetic field of earth; however, they are vulnerable to ambient magneti...
Article
Misalignment angle is an important error in the integration of the Strapdown Inertial Navigation System (SINS) and the Global Positioning System (GPS). Currently, the popular methods for SINS/GPS integrated system are based on the ground velocity. There are two major defects: (1) not all GPS receivers provide the velocity outputs; (2) the contained...
Article
Full-text available
In this paper, a fast-initial alignment method with angular rate aiding based on robust Kalman filter is proposed. First, the traditional system model of the initial alignment is derived, and the angular rate aiding method in the navigation frame is studied. To address the defects of the traditional angular rate aiding alignment method, the angular...
Article
In this paper, an in-motion coarse alignment based on the optimization-based method and vector observation for strapdown inertial navigation system is proposed. The traditional coarse alignment method converges slowly on the moving base, owing to the measurement noises of the observation measurements. To solve this problem, the method of sliding fi...
Article
Full-text available
In tracking a maneuverable target, a proper estimation method with better filtering accuracy, stronger robustness and faster convergence speed is crucial to the tracking system. The performance of conventional nonlinear Gaussian approximate filters may decline when the target engages in abrupt state changes or the noise covariance matrix is unknown...
Article
By analyzing the error models of the measured vectors of the gravitational apparent motion, an in-motion filter-QUEST alignment method only with the inertial measurement unit is presented in this paper. The contribution of the proposed method lies in constructing the in-motion model of the measured vectors of the gravitational apparent motion and d...
Article
Full-text available
In this paper, we proposed a coarse-alignment method for strapdown inertial navigation systems based on attitude determination. The observation vectors, which can be obtained by inertial sensors, usually contain various types of noise, which affects the convergence rate and the accuracy of the coarse alignment. Given this drawback, we studied an at...
Article
An interlaced matrix Kalman filter, which is based on vector observations and gyro measurements, is proposed for spacecraft attitude estimation in this paper. It combines the matrix Kalman filter and cubature Kalman filter to estimate spacecraft attitude and gyro drift bias, respectively. The defects of the original matrix Kalman filter, which coul...
Article
Full-text available
In this paper, a coarse alignment method based on apparent gravitational motion is proposed. Due to the interference of the complex situations, the true observation vectors, which are calculated by the apparent gravity, are contaminated. The sources of the interference are analyzed in detail, and then a low-pass digital filter is designed in this p...
Article
In this paper, an in-motion coarse alignment method is proposed based on the reconstructed observation vectors. Since the complicated noises are contained in the outputs of the inertial sensors, the components of measurement observation vectors, which are constructed by the sensors’ outputs, are analyzed in detail. To suppress the high-frequency no...
Article
Full-text available
In this paper, a self-alignment method for strapdown inertial navigation systems based on the q-method is studied. In addition, an improved method based on integrating gravitational apparent motion to form apparent velocity is designed, which can reduce the random noises of the observation vectors. For further analysis, a novel self-alignment metho...
Conference Paper
A modified solidification method coarse alignment based on recursive quaternion estimator algorithm (REQUEST) is proposed to solve the problem of coarse alignment of vehicle strapdown inertial navigation system (SINS). According to the solidification method, the solution of initial attitude matrix is transferred into the calculation of a constant a...
Article
An anti-disturbance initial alignment algorithm with quaternion adaptive Kalman filter is presented for strap-down inertial navigation system (SINS). By transforming the problem of initial alignment into Wahba attitude determination, the measurement model with quaternion is built directly, and an adaptive Kalman filter is adopted to estimate the in...
Article
Traditional g-based coarse alignment in SINS has two problems under the influences of sensor noises. The first one is that the effective gravitational apparent motion information is difficult to extract, and the second is how to avoid the collinear problem between two vectors. To solve these two problems, a new algorithm based on an improved Kalman...
Conference Paper
A novel interlaced matrix Kalman filter (IMKF) is proposed in this study for spacecraft attitude estimation, which using vector observations and gyro measurements. It combines the matrix Kalman filter (MKF) and cubature Kalman filter (CKF) to estimate spacecraft attitude and gyro drift bias, this method overcomes the defects of the traditional MKF...

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