针对捷联式惯性导航系统(SINS)/全球定位系统(GPS)组合导航系统模型的误差以及粒子滤波(PF)存在的粒子退化问题,结合无迹卡尔曼滤波(UKF)算法,提出一种基于PF-UKF组合滤波的SINS/GPS组合导航系统空中对准方法.由误差四元数代替姿态角,以SINS和GPS的位置差和速度差作为观测量,建立新的组合导航系统误差方程.所提出的PF-UKF组合滤波算法将采样粒子分为随机粒子和确定粒子,其中随机粒子为概率密度函数所采集,确定粒子为UKF中采集Sigma点后所求取的系统状态值.由此降低了PF处理粒子时的复杂程度以及粒子退化的程度.仿真结果表明:相比于UKF算法,该方法有效提高了组合导航系统的精度,具有较好的鲁棒性.

As an important means of underwater navigation and positioning, the accuracy of SINS/DVL integrated navigation system greatly affects the efficiency of underwater work. Considering the complexity and change of the underwater environment, it is necessary to enhance the robustness and adaptability of the SINS/DVL integrated navigation system. Therefore, this paper proposes a new adaptive filter based on support vector regression. The method abandons the elimination of outliers generated by Doppler Velocity Logger (DVL) in the measurement process from the inside of the filter in the form of probability density function modeling. Instead, outliers are eliminated from the perspective of external sensors, which effectively improves the robustness of the filter. At the same time, a new Variational Bayesian (VB) strategy is adopted to reduce the influence of inaccurate process noise and measurement noise, and improve the adaptiveness of the filter. Their advantages complement each other, effectively improve the stability of filter. Simulation and ship-borne tests are carried out. The test results show that the method proposed in this paper has higher navigation accuracy.

Operations and maintenance of Offshore Wind Turbines (OWTs) are challenging, with manual operators constantly exposed to hazardous environments. Due to the high task complexity associated with the OWT, the transition to unmanned solutions remains stagnant. Efforts toward unmanned operations have been observed using Unmanned Aerial Vehicles (UAVs) and Unmanned Underwater Vehicles (UUVs) but are limited mostly to visual inspections only. Collaboration strategies between unmanned vehicles have introduced several opportunities that would enable unmanned operations for the OWT maintenance and repair activities. There have been many papers and reviews on collaborative UVs. However, most of the past papers reviewed collaborative UVs for surveillance purposes, search and rescue missions, and agricultural activities. This review aims to present the current capabilities of Unmanned Vehicles (UVs) used in OWT for Inspection, Maintenance, and Repair (IMR) operations. Strategies to implement collaborative UVs for complex tasks and their associated challenges are discussed together with the strategies to solve localization and navigation issues, prolong operation time, and establish effective communication within the OWT IMR operations. This paper also briefly discusses the potential failure modes for collaborative approaches and possible redundancy strategies to manage them. The collaborative strategies discussed herein will be of use to researchers and technology providers in identifying significant gaps that have hindered the implementation of full unmanned systems which have significant impacts towards the net zero strategy.

当深空探测器接近目标行星时,由于目标行星引力快速增加,轨道动力学模型会出现较快的加速度变化.由于噪声协方差不完全已知,所以传统的滤波方法无法获得导航参数的最优估计,难以满足接近段导航系统的性能要求.为满足系统高稳定性和高精度需求,提出一种基于系统噪声协方差的滑动窗口自适应非线性滤波方法.通过构造系统噪声协方差更新函数,使用滑动窗口对噪声协方差平稳化处理,将速度噪声引起的误差与位置噪声引起的误差隔离开,实时更新所使用的滤波参数信息,自适应调节系统噪声协方差.以火星探测器为例进行仿真,仿真结果表明,相对于传统的无迹卡尔曼滤波方法,该方法获取的位置精度和速度精度分别提高90.97%和66.17%,抑制了系统模型上快速变化的积分误差,并解决传统滤波方法的发散问题.此外,分析了滤波周期和窗口大小对导航性能的影响,为深空探测自主导航提供了一种可行的自适应滤波新方法.

为实现驾驶机器人对试验车辆进行精确的转向操纵,提出了一种驾驶机器人转向操纵的动态模型预测控制方法.建立了驾驶机器人与被操纵车辆的耦合动力学模型,并对耦合模型的可控性进行判别.利用卡尔曼滤波器对耦合模型进行状态估计,并结合估计状态设计了模型预测控制器.将最小二乘法用于路径曲率与预测时域的非线性关系的拟合,设计了具有可变预测时域的动态模型预测控制器.进行了不同驾驶工况下的驾驶机器人转向操纵仿真与试验,研究结果表明了所提方法的有效性.

Singe-beacon localization technology can help Autonomous Underwater Vehicles (AUVs) to obtain precise positions by deploying only one beacon. It is considered as a promising way, benefiting from saving much time and labor compared with traditional Long-Baseline Localization (LBL). A typical single-beacon localization scheme contains two essential questions: the initial observability problem and long-endurance trajectory tracking problem. Aiming at these core problems, a comprehensive solution for single-beacon localization is described in this paper. An multi-hypothesis initial position discriminant method is proposed firstly, which helps to achieve accurate initial location based on observability analysis. Then, an Adaptive Network Fuzzy Inference System (ANFIS)-improved Extended Kalman Filter (EKF) method is proposed, in which single-beacon measuring information is fused with off-the-shelf sensors, including DVL, Compass, etc. ANFIS-EKF can help to improve trajectory tracking precisions by restraining the heavy loss of linearization in conventional EKF. Both simulation and field tests are conducted to verify the performance of the proposed algorithms.

针对传统CKF算法在解决高维问题时因非局部采样造成的滤波性能下降问题，基于设计的正交矩阵提出了一种改进的CKF算法。采用多元Taylor级数展开，揭示了CKF虽能解决UKF的数值不稳定性问题，但同时也引入了非局部采样问题这一事实；进一步设计出一种正交变换矩阵，用于对CKF算法中的采样点进行变换，并从理论上证明了提出的改进CKF算法相对于CKF在高维、强非线性等非局部采样问题突出的应用场合具有更高的估计精度。仿真结果验证了算法的有效性。

In order to solve the nonlocal sampling problem inherent in CKF for high dimensional problems, a new methodology based on orthogonal matrix is proposed in this paper. The performance of the UT is analyzed based on the multi-dimensional Taylor series, to illustrate that even the problem of numerical instability of UKF can be solved by CKF, but the nonlocal sampling problem is introduced. Through the orthogonal matrix the new algorithm named ICKF is proposed in this paper. It is proved theoretically that ICKF has higher estimation accuracy than CKF in the high-dimentional and strongly nonlinearity situation, where local sampling problems is prominent. Simulation example verifies the effectiveness of the proposed algorithm.

Many differential equations of practical interest evolve on Lie groups or on \nmanifolds acted upon by Lie groups. The retention of Lie-group structure \nunder discretization is often vital in the recovery of qualitatively correct geometry \nand dynamics and in the minimization of numerical error. Having \nintroduced requisite elements of differential geometry, this paper surveys the \nnovel theory of numerical integrators that respect Lie-group structure, highlighting \ntheory, algorithmic issues and a number of applications.

In the integrated navigation system using extended Kalman filter (EKF), the state error conventionally uses linear approximation to tackle the commonly nonlinear problem. However, this error definition can diverge the filter in some adverse situations due to significant distortion of the linear approximation. By contrast, the nonlinear state error defined in the Lie group satisfies the autonomous equation, which thus has distinctively better convergence property. This work proposes a novel strapdown inertial navigation system (SINS) nonlinear state error defined in the Lie group and derives the SINS equations of the Lie group EKF (LG-EKF) for the MIMU/GNSS/magnetometer integrated navigation system. The corresponding measurement equations are also derived. A land vehicle field test has been conducted to evaluate the performance of EKF, ST-EKF (state transformation extended Kalman filter) and LG-EKF, which verifies LG-EKF's superior estimation accuracy of the heading angle as well as the other two horizontal angles (pitch and roll). The LG-EKF proposed in this paper is unlimited in the choice of sensors, which means it can be applied with both high-end and low-end inertial sensors.

In response to the lack of specific demonstration and analysis of the research on the necessity of the Lie group strapdown inertial integrated navigation error model based on the Euler angle, two common integrated navigation systems, strapdown inertial navigation system/global navigation satellite system (SINS/GNSS) and strapdown inertial navigation system/doppler velocity log (SINS/DVL), are used as subjects, and the piecewise constant system (PWCS) matrix, based on the Lie group error model, is established. From three aspects of variance estimation, the observability and performance of the system with large misalignment angles for low, medium, and high accuracy levels, traditional error model, Lie group left error model, and right error model are compared. The necessity of research on Lie group error model is analyzed quantitatively and qualitatively. The experimental results show that Lie group error model has better stability of variance estimation, estimation accuracy, and observability than traditional error model, as well as higher practical value.

Because of its high-precision, low-cost and easy-operation, Precise Point Positioning (PPP) becomes a potential and attractive positioning technique that can be applied to self-driving cars and drones. However, the reliability and availability of PPP will be significantly degraded in the extremely difficult conditions where Global Navigation Satellite System (GNSS) signals are blocked frequently. Inertial Navigation System (INS) has been integrated with GNSS to ameliorate such situations in the last decades. Recently, the Visual-Inertial Navigation Systems (VINS) with favorable complementary characteristics is demonstrated to realize a more stable and accurate local position estimation than the INS-only. Nevertheless, the system still must rely on the global positions to eliminate the accumulated errors. In this contribution, we present a semi-tight coupling framework of multi-GNSS PPP and Stereo VINS (S-VINS), which achieves the bidirectional location transfer and sharing in two separate navigation systems. In our approach, the local positions, produced by S-VINS are integrated with multi-GNSS PPP through a graph-optimization based method. Furthermore, the accurate forecast positions with S-VINS are fed back to assist PPP in GNSS-challenged environments. The statistical analysis of a GNSS outage simulation test shows that the S-VINS mode can effectively suppress the degradation of positioning accuracy compared with the INS-only mode. We also carried out a vehicle-borne experiment collecting multi-sensor data in a GNSS-challenged environment. For the complex driving environment, the PPP positioning capability is significantly improved with the aiding of S-VINS. The 3D positioning accuracy is improved by 49.0% for Global Positioning System (GPS), 40.3% for GPS + GLOANSS (Global Navigation Satellite System), 45.6% for GPS + BDS (BeiDou navigation satellite System), and 51.2% for GPS + GLONASS + BDS. On this basis, the solution with the semi-tight coupling scheme of multi-GNSS PPP/S-VINS achieves the improvements of 41.8–60.6% in 3D positioning accuracy compared with the multi-GNSS PPP/INS solutions.

A new robust strap-down inertial navigation system (SINS) and Doppler velocity log (DVL) integrated navigation algorithm are proposed in this paper with a focus on suppressing the process uncertainty and measurement outliers induced by severe manoeuvering. In the proposed algorithm, the one-step predicted probability density function is modeled as Student's t-distribution to deal with the heavy-tailed process noise, and hierarchical Gaussian state-space model for SINS/DVL integrated navigation algorithm is constructed. To detect and eliminate the measurement outliers, each measurement is marked by a binary indicator variable modeled as a beta-Bernoulli distribution. The variational Bayesian approach is used to jointly estimate state vector, auxiliary random variable, scale matrix, Bernoulli variable, and beta variable. The experimental results illustrate that the proposed algorithm has better robustness and navigation accuracy to deal with process uncertainty and measurement outliers than existing state-of-the-art algorithms.

惯导姿态、速度状态量同时纳入一个群中, 且按照误差的两种定义可构成李群左误差模型和右误差模型。针对基于欧拉角的两种李群误差模型进行了比较研究, 分析了两种李群误差模型的差异。针对捷联惯性导航系统(strapdown inertial navigation system, SINS)/全球定位系统(global position system, GPS)和SINS/多普勒计程仪(Doppler velocity log, DVL)两种典型组合导航系统应用, 提出合适的误差模型选择方案。车载和船载实验结果表明, 两种李群误差模型分别更适用于SINS/GPS和SINS/DVL组合导航系统, 尤其是在大失准角条件下效果更为显著, 两种李群误差模型具有更好的定位精度、收敛速度和稳定性。

The attitude and velocity of inertial navigation are included in a group at the same time. Accor-ding to two kinds of definition of error, the left error model and right error model of Lie group are formed. In view of two Lie group error models based on Euler angles, a comparison and analysis of two error models are carried out, and the difference of two error models based on Lie group is given. In view of two typical integrated navigation system of strapdown inertial navigation system (SINS)/global position system (GPS) and SINS/Doppler velocity log (DVL), a suitable error model selection scheme is proposed. The vehicle test and boat test results show that the two error models based on Lie Group are more suitable to SINS/GPS and SINS/DVL respectively, especially with large initial misalignment angles. The selected error model has a better position accuracy, convergence speed and stability.

An accurate state of charge (SOC) estimation is vital for safe operation and efficient management of lithium-ion batteries. To improve the accuracy and robustness, an adaptive and robust square root cubature Kalman filter based on variational Bayesian approximation and Huber’s M-estimation (VB-HASRCKF) is proposed. The variational Bayesian (VB) approximation is used to improve the adaptivity by simultaneously estimating the measurement noise covariance and the SOC, while Huber’s M-estimation is employed to enhance the robustness with respect to the outliers in current and voltage measurements caused by adverse operating conditions. A constant-current discharge test and an urban dynamometer driving schedule (UDDS) test are performed to verify the effectiveness and superiority of the proposed algorithm by comparison with the square root cubature Kalman filter (SRCKF), the VB-based SRCKF, and the Huber-based SRCKF. The experimental results show that the proposed VB-HASRCKF algorithm outperforms the other three filters in terms of SOC estimation accuracy and robustness, with a little higher computation complexity.