对深度神经网络（DNN）进行了训练，以估计在城市区域驾驶的汽车速度，并输入来自低成本六轴惯性测量单元（IMU）的测量流。通过在配备了全球导航卫星系统（GNSS）实时运动学（RTK）定位设备和同步IMU的汽车中，通过驾驶以色列阿什杜德市（Ashdod）驾驶以色列市Ashdod市收集了三个小时的数据。使用以50 Hz的高速率获得的位置测量值计算了汽车速度的地面真实标签。提出了具有长短期内存层的DNN体系结构，以实现高频速度估计，以说明以前的输入历史记录和速度，加速度和角速度之间的非线性关系。制定了简化的死亡算法定位方案，以评估训练有素的模型，该模型提供了速度伪测量。训练有素的模型显示可在4分钟车程中大大提高位置准确性，而无需使用GNSS位置更新。

惯性导航系统与全球导航卫星系统之间的融合经常用于许多平台，例如无人机，陆地车辆和船舶船只。融合通常是在基于模型的扩展卡尔曼过滤框架中进行的。过滤器的关键参数之一是过程噪声协方差。它负责实时解决方案的准确性，因为它考虑了车辆动力学不确定性和惯性传感器质量。在大多数情况下，过程噪声被认为是恒定的。然而，由于整个轨迹的车辆动力学和传感器测量变化，过程噪声协方差可能会发生变化。为了应对这种情况，文献中建议了几种基于自适应的Kalman过滤器。在本文中，我们提出了一个混合模型和基于学习的自适应导航过滤器。我们依靠基于模型的Kalman滤波器和设计深神网络模型来调整瞬时系统噪声协方差矩阵，仅基于惯性传感器读数。一旦学习了过程噪声协方差，就可以将其插入建立的基于模型的Kalman滤波器中。在推导了提出的混合框架后，提出了使用四极管的现场实验结果，并给出了与基于模型的自适应方法进行比较。我们表明，所提出的方法在位置误差中获得了25％的改善。此外，提出的混合学习方法可以在任何导航过滤器以及任何相关估计问题中使用。

A reliable pose estimator robust to environmental disturbances is desirable for mobile robots. To this end, inertial measurement units (IMUs) play an important role because they can perceive the full motion state of the vehicle independently. However, it suffers from accumulative error due to inherent noise and bias instability, especially for low-cost sensors. In our previous studies on Wheel-INS \cite{niu2021, wu2021}, we proposed to limit the error drift of the pure inertial navigation system (INS) by mounting an IMU to the wheel of the robot to take advantage of rotation modulation. However, it still drifted over a long period of time due to the lack of external correction signals. In this letter, we propose to exploit the environmental perception ability of Wheel-INS to achieve simultaneous localization and mapping (SLAM) with only one IMU. To be specific, we use the road bank angles (mirrored by the robot roll angles estimated by Wheel-INS) as terrain features to enable the loop closure with a Rao-Blackwellized particle filter. The road bank angle is sampled and stored according to the robot position in the grid maps maintained by the particles. The weights of the particles are updated according to the difference between the currently estimated roll sequence and the terrain map. Field experiments suggest the feasibility of the idea to perform SLAM in Wheel-INS using the robot roll angle estimates. In addition, the positioning accuracy is improved significantly (more than 30\%) over Wheel-INS. Source code of our implementation is publicly available (https://github.com/i2Nav-WHU/Wheel-SLAM).

自动水下车辆（AUV）执行各种应用，例如海底映射和水下结构健康监测。通常，由多普勒速度日志（DVL）提供的惯性导航系统用于提供车辆的导航解决方案。在这种融合中，DVL提供了AUV的速度向量，从而确定导航解决方案的准确性并有助于估计导航状态。本文提出了BeamsNet，这是一个端到端的深度学习框架，用于回归估计的DVL速度向量，以提高速度向量估算的准确性，并可以替代基于模型的方法。提出了两个版本的BeamsNet，其输入与网络不同。第一个使用当前的DVL光束测量和惯性传感器数据，而另一个仅利用DVL数据，对回归过程进行了当前和过去的DVL测量值。进行了模拟和海上实验，以验证相对于基于模型的方法的拟议学习方法。使用地中海的Snapir AUV进行了海洋实验，收集了大约四个小时的DVL和惯性传感器数据。我们的结果表明，提出的方法在估计DVL速度矢量方面取得了超过60％的改善。

滑动检测对于在外星人表面驾驶的流浪者的安全性和效率至关重要。当前的行星流动站滑移检测系统依赖于视觉感知，假设可以在环境中获得足够的视觉特征。然而，基于视觉的方法容易受到感知降解的行星环境，具有主要低地形特征，例如岩石岩，冰川地形，盐散发物以及较差的照明条件，例如黑暗的洞穴和永久阴影区域。仅依靠视觉传感器进行滑动检测也需要额外的计算功率，并降低了流动站的遍历速率。本文回答了如何检测行星漫游者的车轮滑移而不取决于视觉感知的问题。在这方面，我们提出了一个滑动检测系统，该系统从本体感受的本地化框架中获取信息，该框架能够提供数百米的可靠，连续和计算有效的状态估计。这是通过使用零速度更新，零角度更新和非独立限制作为惯性导航系统框架的伪测量更新来完成的。对所提出的方法进行了对实际硬件的评估，并在行星 - 分析环境中进行了现场测试。该方法仅使用IMU和车轮编码器就可以达到150 m左右的92％滑动检测精度。

近年来，基于数据驱动的导航和定位方法吸收了注意力，并且在准确性和效率方面优于其所有竞争对手方法。本文介绍了一种称为IMUNET的新体系结构，该架构是对边缘设备实现的位置估算的准确和有效效率，该估算接收了一系列RAW IMU测量。该体系结构已与最新的CNN网络的一维版本进行了比较，该网络最近介绍了用于Edge设备实现的精确性和效率。此外，已经提出了一种使用IMU传感器和Google Arcore API收集数据集的新方法，并已记录了公开可用的数据集。使用四个不同的数据集以及提出的数据集和实际设备实现的全面评估已经证明了体系结构的性能。 Pytorch和Tensorflow框架以及Android应用程序代码中的所有代码都已共享，以改善进一​​步的研究。

A reliable self-contained navigation system is essential for autonomous vehicles. Based on our previous study on Wheel-INS \cite{niu2019}, a wheel-mounted inertial measurement unit (Wheel-IMU)-based dead reckoning (DR) system, in this paper, we propose a multiple IMUs-based DR solution for the wheeled robots. The IMUs are mounted at different places of the wheeled vehicles to acquire various dynamic information. In particular, at least one IMU has to be mounted at the wheel to measure the wheel velocity and take advantages of the rotation modulation. The system is implemented through a distributed extended Kalman filter structure where each subsystem (corresponding to each IMU) retains and updates its own states separately. The relative position constraints between the multiple IMUs are exploited to further limit the error drift and improve the system robustness. Particularly, we present the DR systems using dual Wheel-IMUs, one Wheel-IMU plus one vehicle body-mounted IMU (Body-IMU), and dual Wheel-IMUs plus one Body-IMU as examples for analysis and comparison. Field tests illustrate that the proposed multi-IMU DR system outperforms the single Wheel-INS in terms of both positioning and heading accuracy. By comparing with the centralized filter, the proposed distributed filter shows unimportant accuracy degradation while holds significant computation efficiency. Moreover, among the three multi-IMU configurations, the one Body-IMU plus one Wheel-IMU design obtains the minimum drift rate. The position drift rates of the three configurations are 0.82\% (dual Wheel-IMUs), 0.69\% (one Body-IMU plus one Wheel-IMU), and 0.73\% (dual Wheel-IMUs plus one Body-IMU), respectively.

Accurate and smooth global navigation satellite system (GNSS) positioning for pedestrians in urban canyons is still a challenge due to the multipath effects and the non-light-of-sight (NLOS) receptions caused by the reflections from surrounding buildings. The recently developed factor graph optimization (FGO) based GNSS positioning method opened a new window for improving urban GNSS positioning by effectively exploiting the measurement redundancy from the historical information to resist the outlier measurements. Unfortunately, the FGO-based GNSS standalone positioning is still challenged in highly urbanized areas. As an extension of the previous FGO-based GNSS positioning method, this paper exploits the potential of the pedestrian dead reckoning (PDR) model in FGO to improve the GNSS standalone positioning performance in urban canyons. Specifically, the relative motion of the pedestrian is estimated based on the raw acceleration measurements from the onboard smartphone inertial measurement unit (IMU) via the PDR algorithm. Then the raw GNSS pseudorange, Doppler measurements, and relative motion from PDR are integrated using the FGO. Given the context of pedestrian navigation with a small acceleration most of the time, a novel soft motion model is proposed to smooth the states involved in the factor graph model. The effectiveness of the proposed method is verified step-by-step through two datasets collected in dense urban canyons of Hong Kong using smartphone-level GNSS receivers. The comparison between the conventional extended Kalman filter, several existing methods, and FGO-based integration is presented. The results reveal that the existing FGO-based GNSS standalone positioning is highly complementary to the PDR's relative motion estimation. Both improved positioning accuracy and trajectory smoothness are obtained with the help of the proposed method.

自动水下车辆（AUV）通常在许多水下应用中使用。最近，在文献中，多旋翼无人自动驾驶汽车（UAV）的使用引起了更多关注。通常，两个平台都采用惯性导航系统（INS）和协助传感器进行准确的导航解决方案。在AUV导航中，多普勒速度日志（DVL）主要用于帮助INS，而对于无人机，通常使用全球导航卫星系统（GNSS）接收器。辅助传感器和INS之间的融合需要在估计过程中定义步长参数。它负责解决方案频率更新，并最终导致其准确性。步长的选择在计算负载和导航性能之间构成了权衡。通常，与INS操作频率（数百个HERTZ）相比，帮助传感器更新频率要慢得多。对于大多数平台来说，这种高率是不必要的，特别是对于低动力学AUV。在这项工作中，提出了基于监督机器学习的自适应调整方案，以选择适当的INS步骤尺寸。为此，定义了一个速度误差，允许INS/DVL或INS/GNSS在亚最佳工作条件下起作用，并最大程度地减少计算负载。模拟和现场实验的结果显示了使用建议的方法的好处。此外，建议的框架可以应用于任何类型的传感器或平台之间的任何其他融合场景。

通过实现复杂场景实现长期漂移相机姿势估计的目标，我们提出了一种全球定位框架，融合了多层的视觉，惯性和全球导航卫星系统（GNSS）测量。不同于以前的松散和紧密耦合的方法，所提出的多层融合允许我们彻底校正视觉测量仪的漂移，并在GNSS降解时保持可靠的定位。特别地，通过融合GNSS的速度，在紧紧地集成的情况下，解决视觉测量测量测量测量率和偏差估计中的尺度漂移和偏差估计的问题的问题，惯性测量单元（IMU）的预集成以及紧密相机测量的情况下 - 耦合的方式。在外层中实现全局定位，其中局部运动进一步与GNSS位置和基于长期时期的过程以松散耦合的方式融合。此外，提出了一种专用的初始化方法，以保证所有状态变量和参数的快速准确估计。我们为室内和室外公共数据集提供了拟议框架的详尽测试。平均本地化误差减少了63％，而初始化精度与最先进的工程相比，促销率为69％。我们已将算法应用于增强现实（AR）导航，人群采购高精度地图更新等大型应用。

准确的本地化是机器人导航系统的核心组成部分。为此，全球导航卫星系统（GNSS）可以在户外提供绝对的测量，因此消除了长期漂移。但是，将GNSS数据与其他传感器数据进行融合并不是微不足道的，尤其是当机器人在有和没有天空视图的区域之间移动时。我们提出了一种可靠的方法，该方法将原始GNSS接收器数据与惯性测量以及可选的LIDAR观测值紧密地融合在一起，以进行精确和光滑的移动机器人定位。提出了具有两种类型的GNSS因子的因子图。首先，基于伪龙的因素，该因素允许地球上进行全球定位。其次，基于载体阶段的因素，该因素可以实现高度准确的相对定位，这在对其他感应方式受到挑战时很有用。与传统的差异GNS不同，这种方法不需要与基站的连接。在公共城市驾驶数据集上，我们的方法达到了与最先进的算法相当的精度，该算法将视觉惯性探测器与GNSS数据融合在一起 - 尽管我们的方法不使用相机，但仅使用了惯性和GNSS数据。我们还使用来自汽车的数据以及在森林（例如森林）的环境中移动的四倍的机器人，证明了方法的鲁棒性。全球地球框架中的准确性仍然为1-2 m，而估计的轨迹无不连续性和光滑。我们还展示了如何紧密整合激光雷达测量值。我们认为，这是第一个将原始GNSS观察（而不是修复）与LIDAR融合在一起的系统。

Visual Inertial Odometry (VIO) is one of the most established state estimation methods for mobile platforms. However, when visual tracking fails, VIO algorithms quickly diverge due to rapid error accumulation during inertial data integration. This error is typically modeled as a combination of additive Gaussian noise and a slowly changing bias which evolves as a random walk. In this work, we propose to train a neural network to learn the true bias evolution. We implement and compare two common sequential deep learning architectures: LSTMs and Transformers. Our approach follows from recent learning-based inertial estimators, but, instead of learning a motion model, we target IMU bias explicitly, which allows us to generalize to locomotion patterns unseen in training. We show that our proposed method improves state estimation in visually challenging situations across a wide range of motions by quadrupedal robots, walking humans, and drones. Our experiments show an average 15% reduction in drift rate, with much larger reductions when there is total vision failure. Importantly, we also demonstrate that models trained with one locomotion pattern (human walking) can be applied to another (quadruped robot trotting) without retraining.

安装在微空中车辆（MAV）上的地面穿透雷达是有助于协助人道主义陆地间隙的工具。然而，合成孔径雷达图像的质量取决于雷达天线的准确和精确运动估计以及与MAV产生信息性的观点。本文介绍了一个完整的自动空气缩进的合成孔径雷达（GPSAR）系统。该系统由空间校准和时间上同步的工业级传感器套件组成，使得在地面上方，雷达成像和光学成像。自定义任务规划框架允许在地上控制地上的Stripmap和圆形（GPSAR）轨迹的生成和自动执行，以及空中成像调查飞行。基于因子图基于Dual接收机实时运动（RTK）全局导航卫星系统（GNSS）和惯性测量单元（IMU）的测量值，以获得精确，高速平台位置和方向。地面真理实验表明，传感器时机为0.8美元，正如0.1美元的那样，定位率为1 kHz。与具有不确定标题初始化的单个位置因子相比，双位置因子配方可提高高达40％，批量定位精度高达59％。我们的现场试验验证了本地化准确性和精度，使得能够相干雷达测量和检测在沙子中埋入的雷达目标。这验证了作为鸟瞰着地图检测系统的潜力。

最近，数据驱动的惯性导航方法已经证明了它们使用训练有素的神经网络的能力，以获得来自惯性测量单元（IMU）测量的精确位置估计。在本文中，我们提出了一种用于惯性导航〜（CTIN）的基于鲁棒的基于变压器的网络，以准确地预测速度和轨迹。为此，我们首先通过本地和全局多头自我注意力增强基于Reset的编码器，以捕获来自IMU测量的空间上下文信息。然后，我们通过在变压器解码器中利用多针头注意，使用时间知识来熔化这些空间表示。最后，利用不确定性减少的多任务学习，以提高速度和轨迹的学习效率和预测准确性。通过广泛的实验在各种惯性数据集中〜（例如，ridi，oxiod，ronin，偶像和我们自己的），CTIN非常坚固，优于最先进的模型。

The performance of inertial navigation systems is largely dependent on the stable flow of external measurements and information to guarantee continuous filter updates and bind the inertial solution drift. Platforms in different operational environments may be prevented at some point from receiving external measurements, thus exposing their navigation solution to drift. Over the years, a wide variety of works have been proposed to overcome this shortcoming, by exploiting knowledge of the system current conditions and turning it into an applicable source of information to update the navigation filter. This paper aims to provide an extensive survey of information aided navigation, broadly classified into direct, indirect, and model aiding. Each approach is described by the notable works that implemented its concept, use cases, relevant state updates, and their corresponding measurement models. By matching the appropriate constraint to a given scenario, one will be able to improve the navigation solution accuracy, compensate for the lost information, and uncover certain internal states, that would otherwise remain unobservable.

本文提出了一种轻巧，有效的校准神经网络模型，用于降低低成本微电力系统（MEMS）陀螺仪，并实时估算机器人的态度。关键思想是从惯性测量单元（IMU）测量的时间窗口中提取本地和全局特征，以动态地回归陀螺仪的输出补偿组件。遵循精心推导的数学校准模型，LGC-NET利用深度可分离的卷积捕获截面特征并减少网络模型参数。较大的内核注意力旨在更好地学习远程依赖性和特征表示。在EUROC和TUM-VI数据集中评估了所提出的算法，并在具有更轻巧模型结构的（看不见的）测试序列上实现了最先进的测试。尽管它不采用视觉传感器，但与我们的LGC-NET的估计取向与排名最高的视觉惯性探针系统相当。我们在：https：//github.com/huazai665/lgc-net上进行开源方法

移动机器人用于工业，休闲和军事应用。在某些情况下，机器人导航解决方案仅依赖于惯性传感器，因此，导航解决方案会及时漂移。在本文中，我们提出了MORPI框架，这是一种移动机器人纯惯性方法。机器人没有以直线轨迹行进，而是以周期性运动轨迹移动，以实现峰值估计。以这种方式，使用经验公式来估计行进距离，而不是进行三个集成来计算经典惯性解决方案中的机器人位置。提出了两种类型的MORPI方法，其中一种方法基于加速度计和陀螺仪读数，而另一种仅基于陀螺仪。封闭形式的分析溶液被得出表明，与经典的纯惯性溶液相比，MORPI产生较低的位置误差。此外，为了评估所提出的方法，使用配备两种类型的惯性传感器的移动机器人进行现场实验。总共收集了143个轨迹，持续时间为75分钟并评估。结果表明使用我们的方法的好处。为了促进拟议方法的进一步开发，数据集和代码均可在https://github.com/ansfl/morpi上公开获得。

在本文中，提出了一种深入的学习方法，可以在全球导航卫星系统（GNSS）剥夺环境中精确定位轮式车辆。在没有GNSS信号的情况下，可以使用关于从车轮编码器记录的车辆（或其他机器人相似的车轮）速度的信息来通过车辆的线性速度的整合来提供用于车辆的连续定位信息流离失所。然而，来自车轮速度测量的位移估计的特征在于不确定因素，其可以表现为车轮滑动或/和对轮胎尺寸或压力的变化，从潮湿和泥泞的道路驱动器或轮胎佩戴。因此，我们利用深度学习的最近进步提出了车轮内径神经网络（WHONET）来学习校正和准确定位所需的车轮速度测量中的不确定性。首先在若干具有挑战性的驾驶场景中评估所提出的WHONET的性能，例如环形交叉路口，锋利的转弯，硬制动和湿路（漂移）。然后，在长期GNSS中断场景中进一步且广泛地评估WHONET的性能，分别在493km的总距离上的长期GNSS中断场景。获得的实验结果表明，在任何180多个行驶之后，所提出的方法能够准确地定位其原始对应物的定位误差高达93％的车辆。 Whonet的实现可以在https://github.com/onyekpeu/whonet找到。

The field of autonomous mobile robots has undergone dramatic advancements over the past decades. Despite achieving important milestones, several challenges are yet to be addressed. Aggregating the achievements of the robotic community as survey papers is vital to keep the track of current state-of-the-art and the challenges that must be tackled in the future. This paper tries to provide a comprehensive review of autonomous mobile robots covering topics such as sensor types, mobile robot platforms, simulation tools, path planning and following, sensor fusion methods, obstacle avoidance, and SLAM. The urge to present a survey paper is twofold. First, autonomous navigation field evolves fast so writing survey papers regularly is crucial to keep the research community well-aware of the current status of this field. Second, deep learning methods have revolutionized many fields including autonomous navigation. Therefore, it is necessary to give an appropriate treatment of the role of deep learning in autonomous navigation as well which is covered in this paper. Future works and research gaps will also be discussed.

GNSS and LiDAR odometry are complementary as they provide absolute and relative positioning, respectively. Their integration in a loosely-coupled manner is straightforward but is challenged in urban canyons due to the GNSS signal reflections. Recent proposed 3D LiDAR-aided (3DLA) GNSS methods employ the point cloud map to identify the non-line-of-sight (NLOS) reception of GNSS signals. This facilitates the GNSS receiver to obtain improved urban positioning but not achieve a sub-meter level. GNSS real-time kinematics (RTK) uses carrier phase measurements to obtain decimeter-level positioning. In urban areas, the GNSS RTK is not only challenged by multipath and NLOS-affected measurement but also suffers from signal blockage by the building. The latter will impose a challenge in solving the ambiguity within the carrier phase measurements. In the other words, the model observability of the ambiguity resolution (AR) is greatly decreased. This paper proposes to generate virtual satellite (VS) measurements using the selected LiDAR landmarks from the accumulated 3D point cloud maps (PCM). These LiDAR-PCM-made VS measurements are tightly-coupled with GNSS pseudorange and carrier phase measurements. Thus, the VS measurements can provide complementary constraints, meaning providing low-elevation-angle measurements in the across-street directions. The implementation is done using factor graph optimization to solve an accurate float solution of the ambiguity before it is fed into LAMBDA. The effectiveness of the proposed method has been validated by the evaluation conducted on our recently open-sourced challenging dataset, UrbanNav. The result shows the fix rate of the proposed 3DLA GNSS RTK is about 30% while the conventional GNSS-RTK only achieves about 14%. In addition, the proposed method achieves sub-meter positioning accuracy in most of the data collected in challenging urban areas.