1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become ...1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.展开更多
In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited ...In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.展开更多
As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of...As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.展开更多
This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification metho...This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.展开更多
Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including at...Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.展开更多
Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation sys...Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation systems face challenges such as high equipment costs,complex operation,bulky size,and insufficient anti-interference performance.To address these limitations,our study developed and validated a novel portable electromagnetic neuronavigation system designed to improve the precision,accessibility,and clinical applicability of electromagnetic navigation technology in cranial surgery.Methods The software and hardware architecture of a portable neural magnetic navigation system was designed.The key technologies of the system were analysed,including electromagnetic positioning algorithms,miniaturized sensor design,optimization of electromagnetic positioning and navigation algorithms,anti-interference signal processing methods,and fast three-dimensional reconstruction algorithms.A prototype was developed,and its accuracy was tested.Finally,a preliminary clinical application evaluation was conducted.Results This study successfully developed a comprehensive portable electromagnetic neuronavigation system capable of achieving preoperative planning,intraoperative real-time positioning and navigation,and postoperative evaluation of navigation outcomes.Through rigorous collaborative testing of the system’s software and hardware,the accuracy of electromagnetic neuronavigation has been validated to meet clinical requirements.Conclusions This study developed a portable neuroelectromagnetic navigation system and validated its effectiveness and safety through rigorous model testing and preliminary clinical applications.The system is characterized by its compact size,high precision,excellent portability,and user-friendly operation,making it highly valuable for promoting navigation technology and advancing the precision and minimally invasive nature of neurosurgical procedures.展开更多
Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively r...Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively researched for both aerial and underwater navigation applications.However,many TAN systems that rely on recursive Unmanned Aerial Vehicle(UAV)position estimation methods,such as Extended Kalman Filters(EKF),often face challenges with divergence and instability,particularly in highly non-linear systems.To address these issues,this paper proposes and investigates a hybrid two-stage TAN positioning system for UAVs that utilizes Particle Filter.To enhance the system’s robustness against uncertainties caused by noise and to estimate additional system states,a Fuzzy Particle Filter(FPF)is employed in the first stage.This approach introduces a novel terrain composite feature that enables a fuzzy expert system to analyze terrain non-linearities and dynamically adjust the number of particles in real-time.This design allows the UAV to be efficiently localized in GPS-denied environments while also reducing the computational complexity of the particle filter in real-time applications.In the second stage,an Error State Kalman Filter(ESKF)is implemented to estimate the UAV’s altitude.The ESKF is chosen over the conventional EKF method because it is more suitable for non-linear systems.Simulation results demonstrate that the proposed fuzzy-based terrain composite method achieves high positional accuracy while reducing computational time and memory usage.展开更多
Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigati...Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigation.However,with single-channel imaging,surgeons must frequently switch between the surgi⁃cal field and the NIR-II images on the monitor.To address this,a coaxial dual-channel imaging system that com⁃bines visible light and 1100 nm longpass(1100LP)fluorescence was developed.The system features a custom⁃ized coaxial dual-channel lens with optimized distortion,achieving precise alignment with an error of less than±0.15 mm.Additionally,the shared focusing mechanism simplifies operation.Using FDA-approved indocya⁃nine green(ICG),the system was successfully applied in dual-channel guided rat lymph node excision,and blood supply assessment of reconstructed human flap.This approach enhances surgical precision,improves opera⁃tional efficiency,and provides a valuable reference for further clinical translation of NIR-II fluorescence imaging.展开更多
With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation wind...With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation window period is crucial for navigating in the Arctic route,which is of great significance to the selection of the route and the optimization of navigation.This paper introduces the establishment of a risk index system,determination of risk index weight,establishment of a risk evaluation model,and prediction algorithm for the window period.In addition,data sources of both environmental factors and ship factors are introducted,and their shortcomings are analyzed,followed by introduction of various methods involved in window prediction and analysis of their advantages and disadvantages.The quantitative risk evaluation and window period algorithm can provide a reference for the research of polar navigation window period prediction.展开更多
Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant t...Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant tuberculosis(RR-TB)who were hospitalized in the hospital from September 2023 to September 2024 were included.After random equal division,94 patients were included in the control group and received systemic anti-tuberculosis chemotherapy;94 patients were included in the treatment group.Based on systemic anti-tuberculosis treatment,digital subtraction angiography(DSA)technology was used to inject targeted drugs into the bronchial lumen through bronchoscopy to complete anti-tuberculosis treatment.The changes in sputum bacteria and imaging were observed in the two groups.Results:The sputum negative conversion rate in the treatment group was significantly higher than that in the control group(86.2%;70.2%)(u=2.74,P<0.01).The absorption rate of CT imaging lesions(significant absorption)was significantly higher than that of the control group(83.0%;50%)(u=2.45,P<0.05).The closure rate of chest CT cavities was significantly higher than that of the control group(74.2%;39.1%)(u=2.20,P<0.05).During the treatment process,the improvement of clinical symptoms was significantly higher than that of the control group,and the difference was statistically significant.There was no statistically significant difference in the incidence of adverse reactions between the two groups(x^(2)=0.434,P>0.05).Conclusion:Based on DSA,targeted drug infusion within the bronchoscope can significantly improve the efficacy of the disease,with mild adverse reactions that patients can tolerate.It is worthy of promotion and application.展开更多
In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies an...In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies and trajectory planning and often perform poorly in complex environments.To improve the UAV-environment interaction efficiency,this study proposes a multi-UAV integrated navigation algorithm based on Deep Reinforcement Learning(DRL).This algorithm integrates the Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),and Visual Navigation System(VNS)for comprehensive information fusion.Specifically,an improved multi-UAV integrated navigation algorithm called Information Fusion with MultiAgent Deep Deterministic Policy Gradient(IF-MADDPG)was developed.This algorithm enables UAVs to learn collaboratively and optimize their flight trajectories in real time.Through simulations and experiments,test scenarios in GNSS-denied environments were constructed to evaluate the effectiveness of the algorithm.The experimental results demonstrate that the IF-MADDPG algorithm significantly enhances the collaborative navigation capabilities of multiple UAVs in formation maintenance and GNSS-denied environments.Additionally,it has advantages in terms of mission completion time.This study provides a novel approach for efficient collaboration in multi-UAV systems,which significantly improves the robustness and adaptability of navigation systems.展开更多
Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environ...Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environmental adaptability and struggles to adapt to the variability of crowd density and pedestrian motion patterns.This paper proposes a navigation method that integrates spatiotemporal risk field modeling and adaptive reward optimization,aiming to improve the robot’s decision-making ability in diverse crowd scenarios through dynamic risk assessment and nonlinear weight adjustment.We construct a spatiotemporal risk field model based on a Gaussian kernel function by combining crowd density,relative distance,andmotion speed to quantify environmental complexity and realize crowd-density-sensitive risk assessment dynamically.We apply an exponential decay function to reward design to address the linear conflict problem of fixed weights in multi-objective optimization.We adaptively adjust weight allocation between safety constraints and navigation efficiency based on real-time risk values,prioritizing safety in highly dense areas and navigation efficiency in sparse areas.Experimental results show that our method improves the navigation success rate by 9.0%over state-of-the-art models in high-density scenarios,with a 10.7%reduction in intrusion time ratio.Simulation comparisons validate the risk field model’s ability to capture risk superposition effects in dense scenarios and the suppression of near-field dangerous behaviors by the exponential decay mechanism.Our parametric optimization paradigm establishes an explicit mapping between navigation objectives and risk parameters through rigorous mathematical formalization,providing an interpretable approach for safe deployment of service robots in dynamic environments.展开更多
Taking modern indoor building construction as an example,this study analyzes the path planning and navigation of a smart plastering robot.It includes a basic introduction to smart plastering robots,an analysis of mult...Taking modern indoor building construction as an example,this study analyzes the path planning and navigation of a smart plastering robot.It includes a basic introduction to smart plastering robots,an analysis of multi-sensor fusion localization algorithms for smart plastering robots,and an analysis of path planning and navigation functions for smart plastering robots.It is hoped that through this analysis,a reference is provided for the path planning and navigation design of such robots to meet their practical application needs.展开更多
Mobile robots represented by smart wheelchairs can assist elderly people with mobility difficulties.This paper proposes a multi-mode semi-autonomous navigation system based on a local semantic map for mobile robots,wh...Mobile robots represented by smart wheelchairs can assist elderly people with mobility difficulties.This paper proposes a multi-mode semi-autonomous navigation system based on a local semantic map for mobile robots,which can assist users to implement accurate navigation(e.g.,docking)in the environment without prior maps.In order to overcome the problem of repeated oscillations during the docking of traditional local path planning algorithms,this paper adopts a mode-switching method and uses feedback control to perform docking when approaching semantic goals.At last,comparative experiments were carried out in the real environment.Results show that our method is superior in terms of safety,comfort and docking accuracy.展开更多
The introduction of path planning and visual navigation in vascular interventional surgery can provide an intuitive reference and guidance for doctors.In this study,based on the preprocessing results of vessel skeleto...The introduction of path planning and visual navigation in vascular interventional surgery can provide an intuitive reference and guidance for doctors.In this study,based on the preprocessing results of vessel skeleton extraction and stenosis diagnosis in X-ray coronary angiography images,clustering is used to determine the connectivity of the intersection points,and then the improved Dijkstra algorithm is used to automatically plan the surgical path.On this basis,the intermediate point is introduced to piecewise correct the path and improve the accuracy of the system.Finally,the epipolar constrained inverse projection transformation is used to reconstruct the coronary artery 3D model,and the optimal path is marked to achieve a multi-angle 3D visual navigation.Clinical experimental results show that compared with the traditional Dijkstra algorithm,the improved method can reduce the need for intermediate points,which improves computational efficiency,and the average error of manual calibration path is reduced to 4%of that before overall optimization.The results of 3D reconstruction and reprojection further qualitatively and quantitatively verify the effectiveness of the whole scheme.展开更多
This paper presents a quadcopter system for naviga-tion in outdoor urban environments.The main contributions include the hardware design,the establishment of global occu-pancy grid maps based on millimeter-wave radars...This paper presents a quadcopter system for naviga-tion in outdoor urban environments.The main contributions include the hardware design,the establishment of global occu-pancy grid maps based on millimeter-wave radars,the trajec-tory planning scheme based on optimal virtual tube methods,and the controller structure based on dynamics.The proposed system focuses on utilizing a compact and lightweight quadro-tor with sensors to achieve navigation that conforms to the direction of urban roads with high computational efficiency and safety.Our work is an application of millimeter-wave radars and virtual tube planning for obstacle avoidance in navigation.The validness and effectiveness of the proposed system are verified by experiments.展开更多
Endoscopic transnasal optic nerve decompression surgery plays a crucial role in minimal invasive treatment of complex traumatic optic neuropathy.However,a major challenge faced during the procedure is the inability to...Endoscopic transnasal optic nerve decompression surgery plays a crucial role in minimal invasive treatment of complex traumatic optic neuropathy.However,a major challenge faced during the procedure is the inability to visualize the optic nerve intraoperatively.To address this issue,an endoscopic image-based augmented reality surgical navigation system is developed in this study.The system aims to virtually fuse the optic nerve onto the endoscopic images,assisting surgeons in determining the optic nerve’s position and reducing surgical risks.First,a calibration algorithm based on a checkerboard grid of immobile points is proposed,building upon existing calibration methods.Additionally,to tackle accuracy issues associated with augmented reality technology,an optical navigation and visual fusion compensation algorithm is proposed to improve the intraoperative tracking accuracy.To evaluate the system’s performance,model experiments were meticulously designed and conducted.The results confirm the accuracy and stability of the proposed system,with an average tracking error of(0.99±0.46)mm.This outcome demonstrates the effectiveness of the proposed algorithm in improving the augmented reality surgical navigation system’s accuracy.Furthermore,the system successfully displays hidden optic nerves and other deep tissues,thus showcasing the promising potential for future applications in orbital and maxillofacial surgery.展开更多
The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers wer...The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.展开更多
High-performance positioning,navigation and timing(PNT)service is critical to the safe flight of low-altitude aircraft and the effective management of low altitude traffic.In low-altitude economic sce-narios,the speci...High-performance positioning,navigation and timing(PNT)service is critical to the safe flight of low-altitude aircraft and the effective management of low altitude traffic.In low-altitude economic sce-narios,the specificity of massive unmanned aerial ve-hicle(UAV)flights and the complexity of low-altitude airspace traffic management impose stringent demand on the high-continuity,high-accuracy,real-time,and high-security PNT service.However,the current PNT service,which primarily relies on Global Navigation Satellite System(GNSS),Micro-Electro-Mechanical System Inertial Navigation System(MEMS INS),etc.,is completely inadequate to support the future needs of low-altitude economic development.In order to bridge the huge gap between existing capability and future demand,a three-layer PNT architecture based on the collaboration of space-based,air-based and ground-based PNT systems is proposed for low-altitude econ-omy.The space-based layer consists of high,medium even possible low orbit GNSS constellations,such as BeiDou Navigation Satellite System(BDS),for high-precision,high-security absolute positioning and tim-ing.The air-based layer leverages inter-aircraft links for high-reliability dynamic relative positioning.The ground-based layer includes pseudolite network,as well as 5G-advanced(5G-A)/6G network,for more comprehensive coverage and real-time positioning.To this end,it is imperative to make breakthroughs in key technologies,from systems to airborne terminal,in-cluding but not limited to high-precision anti-jamming GNSS signal processing,high-reliability relative po-sitioning,real-time pseudolite positioning,and high-efficient multi-source information fusion at airborne terminal,etc.Due to the moderate redundancy,hetero-geneous mechanism,and multiple coverage from mul-tiple PNT systems,the proposed layered PNT archi-tecture possesses high robustness and resilient.Addi-tionally,the integration of INS,LiDAR and vision etc.perception technologies can significantly enhance the PNT capability.As a result,the proposed three-layer PNT architecture enable greater autonomy for low-altitude aircraft and intelligent traffic management for massive UAV operations,and promoting the safe and efficient development of the low-altitude economy.展开更多
Visual inertial odometry(VIO)problems have been extensively investigated in recent years.Existing VIO methods usually consider the localization or navigation issues of robots or autonomous vehicles in relatively small...Visual inertial odometry(VIO)problems have been extensively investigated in recent years.Existing VIO methods usually consider the localization or navigation issues of robots or autonomous vehicles in relatively small areas.This paper considers the problem of vision-aided inertial navigation(VIN)for aircrafts equipped with a strapdown inertial navigation system(SINS)and a downward-viewing camera.This is different from the traditional VIO problems in a larger working area with more precise inertial sensors.The goal is to utilize visual information to aid SINS to improve the navigation performance.In the multistate constraint Kalman filter(MSCKF)framework,we introduce an anchor frame to construct necessary models and derive corresponding Jacobians to implement a VIN filter to directly update the position in the Earth-centered Earth-fixed(ECEF)frame and the velocity and attitude in the local level frame by feature measurements.Due to its filtering-based property,the proposed method is naturally low computational demanding and is suitable for applications with high real-time requirements.Simulation and real-world data experiments demonstrate that the proposed method can considerably improve the navigation performance relative to the SINS.展开更多
基金supported by the National Level Project of China (No. 2020-JCJQ-ZQ-059)。
文摘1. Introduction Celestial navigation is a kind of navigation with a long history.With the increasing demand for intelligent autonomy and antielectromagnetic interference in spacecraft, celestial navigation has become one of the current research hotspots in spacecraft autonomous navigation. Spacecraft face complex electromagnetic interference in orbit. The time-varying, non-Gaussian interference from internal devices and external environment can lead to measurement distortion.
基金supported by the National Natural Science Foundation of China(No.U2037602)。
文摘In order to address the challenges encountered in visual navigation for asteroid landing using traditional point features,such as significant recognition and extraction errors,low computational efficiency,and limited navigation accuracy,a novel approach for multi-type fusion visual navigation is proposed.This method aims to overcome the limitations of single-type features and enhance navigation accuracy.Analytical criteria for selecting multi-type features are introduced,which simultaneously improve computational efficiency and system navigation accuracy.Concerning pose estimation,both absolute and relative pose estimation methods based on multi-type feature fusion are proposed,and multi-type feature normalization is established,which significantly improves system navigation accuracy and lays the groundwork for flexible application of joint absolute-relative estimation.The feasibility and effectiveness of the proposed method are validated through simulation experiments through 4769 Castalia.
文摘As the core information infrastructure of modern information warfare,the offensive and defensive confrontations of satellite navigation systems have given rise to navigation warfare,which focuses on seizing control of navigation resources.Based on the space segment,control segment,and user segment of satellite navigation systems,this paper systematically constructs an offensive-defensive technology system for navigation warfare,and deeply analyzes core measures such as signal enhancement and suppression,autonomous navigation and link jamming,anti-jamming reception,and integrated navigation.It extracts key technologies including adaptive nulling antennas,joint filtering,and multi-dimensional combined jamming,and discusses the technical effectiveness of these technologies by incorporating relevant cases.The advantages of navigation warfare stem from multi-segment coordination and technological inte-gration.In the future,the development directions of navigation warfare will focus on three aspects:enhancing satellite capabilities,tackling core technical challenges,and building a multi-dimensional system.
基金supported in part by the Doctoral Initiation Fund of Nanchang Hangkong University(No.EA202403107)Jiangxi Province Early Career Youth Science and Technology Talent Training Project(No.CK202403509).
文摘This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.
基金supported by the Basic Science Center Project of the National Natural Science Foundation of China(42388102)the National Natural Science Foundation of China(42174030)+2 种基金the Special Fund of Hubei Luojia Laboratory(220100020)the Major Science and Technology Program for Hubei Province(2022AAA002)the Fundamental Research Funds for the Central Universities of China(2042022dx0001 and 2042023kfyq01)。
文摘Nonlinear variations in the coordinate time series of global navigation satellite system(GNSS) reference stations are strongly correlated with surface displacements caused by environmental loading effects,including atmospheric, hydrological, and nontidal ocean loading. Continuous improvements in the accuracy of surface mass loading products, performance of Earth models, and precise data-processing technologies have significantly advanced research on the effects of environmental loading on nonlinear variations in GNSS coordinate time series. However, owing to theoretical limitations, the lack of high spatiotemporal resolution surface mass observations, and the coupling of GNSS technology-related systematic errors, environmental loading and nonlinear GNSS reference station displacements remain inconsistent. The applicability and capability of these loading products across different regions also require further evaluation. This paper outlines methods for modeling environmental loading, surface mass loading products, and service organizations. In addition, it summarizes recent advances in applying environmental loading to address nonlinear variations in global and regional GNSS coordinate time series. Moreover, the scientific questions of existing studies are summarized, and insights into future research directions are provided. The complex nonlinear motion of reference stations is a major factor limiting the accuracy of the current terrestrial reference frame. Further refining the environmental load modeling method, establishing a surface mass distribution model with high spatiotemporal resolution and reliability, exploring other environmental load factors such as ice sheet and artificial mass-change effects, and developing an optimal data-processing model and strategy for reprocessing global reference station data consistently could contribute to the development of a millimeter-level nonlinear motion model for GNSS reference stations with actual physical significance and provide theoretical support for establishing a terrestrial reference frame with 1 mm accuracy by 2050.
基金funded by National Natural Science Foundation of China(No.82272134)Innovative Research Group Project of the National Natural Science Foundation of China(No.82272134,Xiao-lei Chen).
文摘Background and Objective Electromagnetic navigation technology has demonstrated significant potential in enhancing the accuracy and safety of neurosurgical procedures.However,traditional electromagnetic navigation systems face challenges such as high equipment costs,complex operation,bulky size,and insufficient anti-interference performance.To address these limitations,our study developed and validated a novel portable electromagnetic neuronavigation system designed to improve the precision,accessibility,and clinical applicability of electromagnetic navigation technology in cranial surgery.Methods The software and hardware architecture of a portable neural magnetic navigation system was designed.The key technologies of the system were analysed,including electromagnetic positioning algorithms,miniaturized sensor design,optimization of electromagnetic positioning and navigation algorithms,anti-interference signal processing methods,and fast three-dimensional reconstruction algorithms.A prototype was developed,and its accuracy was tested.Finally,a preliminary clinical application evaluation was conducted.Results This study successfully developed a comprehensive portable electromagnetic neuronavigation system capable of achieving preoperative planning,intraoperative real-time positioning and navigation,and postoperative evaluation of navigation outcomes.Through rigorous collaborative testing of the system’s software and hardware,the accuracy of electromagnetic neuronavigation has been validated to meet clinical requirements.Conclusions This study developed a portable neuroelectromagnetic navigation system and validated its effectiveness and safety through rigorous model testing and preliminary clinical applications.The system is characterized by its compact size,high precision,excellent portability,and user-friendly operation,making it highly valuable for promoting navigation technology and advancing the precision and minimally invasive nature of neurosurgical procedures.
文摘Terrain Aided Navigation(TAN)technology has become increasingly important due to its effectiveness in environments where Global Positioning System(GPS)is unavailable.In recent years,TAN systems have been extensively researched for both aerial and underwater navigation applications.However,many TAN systems that rely on recursive Unmanned Aerial Vehicle(UAV)position estimation methods,such as Extended Kalman Filters(EKF),often face challenges with divergence and instability,particularly in highly non-linear systems.To address these issues,this paper proposes and investigates a hybrid two-stage TAN positioning system for UAVs that utilizes Particle Filter.To enhance the system’s robustness against uncertainties caused by noise and to estimate additional system states,a Fuzzy Particle Filter(FPF)is employed in the first stage.This approach introduces a novel terrain composite feature that enables a fuzzy expert system to analyze terrain non-linearities and dynamically adjust the number of particles in real-time.This design allows the UAV to be efficiently localized in GPS-denied environments while also reducing the computational complexity of the particle filter in real-time applications.In the second stage,an Error State Kalman Filter(ESKF)is implemented to estimate the UAV’s altitude.The ESKF is chosen over the conventional EKF method because it is more suitable for non-linear systems.Simulation results demonstrate that the proposed fuzzy-based terrain composite method achieves high positional accuracy while reducing computational time and memory usage.
基金Supported by the National Natural Science Foundation of China(U23A20487)the National Key R&D Program of China(2022YFB3206000)+1 种基金Dr.Li Dak Sum&Yip Yio Chin Development Fund for Regenerative Medicine,Zhejiang Universitythe National Natural Science Foundation of China(61975172).
文摘Fluorescence imaging in the second near-infrared window(NIR-II,900-1880 nm)offers high signalto-background ratio(SBR),enhanced definition,and superior tissue penetration,making it ideal for real-time surgical navigation.However,with single-channel imaging,surgeons must frequently switch between the surgi⁃cal field and the NIR-II images on the monitor.To address this,a coaxial dual-channel imaging system that com⁃bines visible light and 1100 nm longpass(1100LP)fluorescence was developed.The system features a custom⁃ized coaxial dual-channel lens with optimized distortion,achieving precise alignment with an error of less than±0.15 mm.Additionally,the shared focusing mechanism simplifies operation.Using FDA-approved indocya⁃nine green(ICG),the system was successfully applied in dual-channel guided rat lymph node excision,and blood supply assessment of reconstructed human flap.This approach enhances surgical precision,improves opera⁃tional efficiency,and provides a valuable reference for further clinical translation of NIR-II fluorescence imaging.
文摘With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation window period is crucial for navigating in the Arctic route,which is of great significance to the selection of the route and the optimization of navigation.This paper introduces the establishment of a risk index system,determination of risk index weight,establishment of a risk evaluation model,and prediction algorithm for the window period.In addition,data sources of both environmental factors and ship factors are introducted,and their shortcomings are analyzed,followed by introduction of various methods involved in window prediction and analysis of their advantages and disadvantages.The quantitative risk evaluation and window period algorithm can provide a reference for the research of polar navigation window period prediction.
基金Science and Education Department Harbin Health Committee Project。
文摘Objective:To observe the guiding role of image navigation technology in the treatment of patients with tuberculosis.Methods:A total of 188 patients with multidrug-resistant tuberculosis(MDR-TB)and rifampin-resistant tuberculosis(RR-TB)who were hospitalized in the hospital from September 2023 to September 2024 were included.After random equal division,94 patients were included in the control group and received systemic anti-tuberculosis chemotherapy;94 patients were included in the treatment group.Based on systemic anti-tuberculosis treatment,digital subtraction angiography(DSA)technology was used to inject targeted drugs into the bronchial lumen through bronchoscopy to complete anti-tuberculosis treatment.The changes in sputum bacteria and imaging were observed in the two groups.Results:The sputum negative conversion rate in the treatment group was significantly higher than that in the control group(86.2%;70.2%)(u=2.74,P<0.01).The absorption rate of CT imaging lesions(significant absorption)was significantly higher than that of the control group(83.0%;50%)(u=2.45,P<0.05).The closure rate of chest CT cavities was significantly higher than that of the control group(74.2%;39.1%)(u=2.20,P<0.05).During the treatment process,the improvement of clinical symptoms was significantly higher than that of the control group,and the difference was statistically significant.There was no statistically significant difference in the incidence of adverse reactions between the two groups(x^(2)=0.434,P>0.05).Conclusion:Based on DSA,targeted drug infusion within the bronchoscope can significantly improve the efficacy of the disease,with mild adverse reactions that patients can tolerate.It is worthy of promotion and application.
基金co-supported by the National Natural Science Foundation of China(Nos.92371201 and 52192633)the Natural Science Foundation of Shaanxi Province of China(No.2022JC-03)the Aeronautical Science Foundation of China(No.ASFC-20220019070002)。
文摘In multiple Unmanned Aerial Vehicles(UAV)systems,achieving efficient navigation is essential for executing complex tasks and enhancing autonomy.Traditional navigation methods depend on predefined control strategies and trajectory planning and often perform poorly in complex environments.To improve the UAV-environment interaction efficiency,this study proposes a multi-UAV integrated navigation algorithm based on Deep Reinforcement Learning(DRL).This algorithm integrates the Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),and Visual Navigation System(VNS)for comprehensive information fusion.Specifically,an improved multi-UAV integrated navigation algorithm called Information Fusion with MultiAgent Deep Deterministic Policy Gradient(IF-MADDPG)was developed.This algorithm enables UAVs to learn collaboratively and optimize their flight trajectories in real time.Through simulations and experiments,test scenarios in GNSS-denied environments were constructed to evaluate the effectiveness of the algorithm.The experimental results demonstrate that the IF-MADDPG algorithm significantly enhances the collaborative navigation capabilities of multiple UAVs in formation maintenance and GNSS-denied environments.Additionally,it has advantages in terms of mission completion time.This study provides a novel approach for efficient collaboration in multi-UAV systems,which significantly improves the robustness and adaptability of navigation systems.
基金supported by the Sichuan Science and Technology Program(2025ZNSFSC0005).
文摘Robot navigation in complex crowd service scenarios,such as medical logistics and commercial guidance,requires a dynamic balance between safety and efficiency,while the traditional fixed reward mechanism lacks environmental adaptability and struggles to adapt to the variability of crowd density and pedestrian motion patterns.This paper proposes a navigation method that integrates spatiotemporal risk field modeling and adaptive reward optimization,aiming to improve the robot’s decision-making ability in diverse crowd scenarios through dynamic risk assessment and nonlinear weight adjustment.We construct a spatiotemporal risk field model based on a Gaussian kernel function by combining crowd density,relative distance,andmotion speed to quantify environmental complexity and realize crowd-density-sensitive risk assessment dynamically.We apply an exponential decay function to reward design to address the linear conflict problem of fixed weights in multi-objective optimization.We adaptively adjust weight allocation between safety constraints and navigation efficiency based on real-time risk values,prioritizing safety in highly dense areas and navigation efficiency in sparse areas.Experimental results show that our method improves the navigation success rate by 9.0%over state-of-the-art models in high-density scenarios,with a 10.7%reduction in intrusion time ratio.Simulation comparisons validate the risk field model’s ability to capture risk superposition effects in dense scenarios and the suppression of near-field dangerous behaviors by the exponential decay mechanism.Our parametric optimization paradigm establishes an explicit mapping between navigation objectives and risk parameters through rigorous mathematical formalization,providing an interpretable approach for safe deployment of service robots in dynamic environments.
基金Science and Technology Research Project of Chongqing Education Commission(Project No.:KJQN202401902)Chongqing Construction Science and Technology Plan Project(Project No.:Chinese Society For Urban Studies,2024:3-24)+1 种基金cientific Research Fund Project of Chongqing Institute of Engineering(Project No.:2022gcky01)College Student Innovation and Entrepreneurship Training Program Project of Chongqing Institute of Engineering(Project No.:CXCY2024018)。
文摘Taking modern indoor building construction as an example,this study analyzes the path planning and navigation of a smart plastering robot.It includes a basic introduction to smart plastering robots,an analysis of multi-sensor fusion localization algorithms for smart plastering robots,and an analysis of path planning and navigation functions for smart plastering robots.It is hoped that through this analysis,a reference is provided for the path planning and navigation design of such robots to meet their practical application needs.
基金the Technology Project Managed by the State Grid Corporation of China(No.5108-202218280A-2-249-XG)。
文摘Mobile robots represented by smart wheelchairs can assist elderly people with mobility difficulties.This paper proposes a multi-mode semi-autonomous navigation system based on a local semantic map for mobile robots,which can assist users to implement accurate navigation(e.g.,docking)in the environment without prior maps.In order to overcome the problem of repeated oscillations during the docking of traditional local path planning algorithms,this paper adopts a mode-switching method and uses feedback control to perform docking when approaching semantic goals.At last,comparative experiments were carried out in the real environment.Results show that our method is superior in terms of safety,comfort and docking accuracy.
基金the National Natural Science Foundation of China(No.61973210)the Interdisciplinary Program of Shanghai Jiao Tong University(Nos.YG2019ZDA17 and ZH2018QNB23)+1 种基金the Shanghai Advanced Technology Joint Research Fund(No.USCAST2020-7)the Shenzhen Science and Technology Commission Key Technology Project(No.JSGG20200701095003006)。
文摘The introduction of path planning and visual navigation in vascular interventional surgery can provide an intuitive reference and guidance for doctors.In this study,based on the preprocessing results of vessel skeleton extraction and stenosis diagnosis in X-ray coronary angiography images,clustering is used to determine the connectivity of the intersection points,and then the improved Dijkstra algorithm is used to automatically plan the surgical path.On this basis,the intermediate point is introduced to piecewise correct the path and improve the accuracy of the system.Finally,the epipolar constrained inverse projection transformation is used to reconstruct the coronary artery 3D model,and the optimal path is marked to achieve a multi-angle 3D visual navigation.Clinical experimental results show that compared with the traditional Dijkstra algorithm,the improved method can reduce the need for intermediate points,which improves computational efficiency,and the average error of manual calibration path is reduced to 4%of that before overall optimization.The results of 3D reconstruction and reprojection further qualitatively and quantitatively verify the effectiveness of the whole scheme.
基金supported by the National Key Research and Development Program of China(2022YFA1004703)the National Natural Science Foundation of China(62088101).
文摘This paper presents a quadcopter system for naviga-tion in outdoor urban environments.The main contributions include the hardware design,the establishment of global occu-pancy grid maps based on millimeter-wave radars,the trajec-tory planning scheme based on optimal virtual tube methods,and the controller structure based on dynamics.The proposed system focuses on utilizing a compact and lightweight quadro-tor with sensors to achieve navigation that conforms to the direction of urban roads with high computational efficiency and safety.Our work is an application of millimeter-wave radars and virtual tube planning for obstacle avoidance in navigation.The validness and effectiveness of the proposed system are verified by experiments.
基金the National Natural Science Foundation of China(Nos.82330063 and M-0019)the Interdisciplinary Program of Shanghai Jiao Tong University(Nos.YG2022QN056,YG2023ZD19,and YG2023ZD15)+2 种基金the Cross Disciplinary Research Fund of Shanghai Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine(No.JYJC202115)the Translation Clinical R&D Project of Medical Robot of Shanghai Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine(No.IMR-NPH202002)the Shanghai Key Clinical Specialty,Shanghai Eye Disease Research Center(No.2022ZZ01003)。
文摘Endoscopic transnasal optic nerve decompression surgery plays a crucial role in minimal invasive treatment of complex traumatic optic neuropathy.However,a major challenge faced during the procedure is the inability to visualize the optic nerve intraoperatively.To address this issue,an endoscopic image-based augmented reality surgical navigation system is developed in this study.The system aims to virtually fuse the optic nerve onto the endoscopic images,assisting surgeons in determining the optic nerve’s position and reducing surgical risks.First,a calibration algorithm based on a checkerboard grid of immobile points is proposed,building upon existing calibration methods.Additionally,to tackle accuracy issues associated with augmented reality technology,an optical navigation and visual fusion compensation algorithm is proposed to improve the intraoperative tracking accuracy.To evaluate the system’s performance,model experiments were meticulously designed and conducted.The results confirm the accuracy and stability of the proposed system,with an average tracking error of(0.99±0.46)mm.This outcome demonstrates the effectiveness of the proposed algorithm in improving the augmented reality surgical navigation system’s accuracy.Furthermore,the system successfully displays hidden optic nerves and other deep tissues,thus showcasing the promising potential for future applications in orbital and maxillofacial surgery.
基金the National Natural Science Foundation of China(No.11502146)the 1 Batch of 2021 MOE of PRC Industry University Collaborative Education Program(No.202101042008)。
文摘The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.
基金supported in part by the National Key R&D Program of China under Grant 2021YFA0716600 and 2024ZD1300100in part by the National Natural Science Foundation of China under Grant 42274018,42425401,62371029,62271285 and U2233217.
文摘High-performance positioning,navigation and timing(PNT)service is critical to the safe flight of low-altitude aircraft and the effective management of low altitude traffic.In low-altitude economic sce-narios,the specificity of massive unmanned aerial ve-hicle(UAV)flights and the complexity of low-altitude airspace traffic management impose stringent demand on the high-continuity,high-accuracy,real-time,and high-security PNT service.However,the current PNT service,which primarily relies on Global Navigation Satellite System(GNSS),Micro-Electro-Mechanical System Inertial Navigation System(MEMS INS),etc.,is completely inadequate to support the future needs of low-altitude economic development.In order to bridge the huge gap between existing capability and future demand,a three-layer PNT architecture based on the collaboration of space-based,air-based and ground-based PNT systems is proposed for low-altitude econ-omy.The space-based layer consists of high,medium even possible low orbit GNSS constellations,such as BeiDou Navigation Satellite System(BDS),for high-precision,high-security absolute positioning and tim-ing.The air-based layer leverages inter-aircraft links for high-reliability dynamic relative positioning.The ground-based layer includes pseudolite network,as well as 5G-advanced(5G-A)/6G network,for more comprehensive coverage and real-time positioning.To this end,it is imperative to make breakthroughs in key technologies,from systems to airborne terminal,in-cluding but not limited to high-precision anti-jamming GNSS signal processing,high-reliability relative po-sitioning,real-time pseudolite positioning,and high-efficient multi-source information fusion at airborne terminal,etc.Due to the moderate redundancy,hetero-geneous mechanism,and multiple coverage from mul-tiple PNT systems,the proposed layered PNT archi-tecture possesses high robustness and resilient.Addi-tionally,the integration of INS,LiDAR and vision etc.perception technologies can significantly enhance the PNT capability.As a result,the proposed three-layer PNT architecture enable greater autonomy for low-altitude aircraft and intelligent traffic management for massive UAV operations,and promoting the safe and efficient development of the low-altitude economy.
基金supported by the National Natural Science Foundation of China(61773306).
文摘Visual inertial odometry(VIO)problems have been extensively investigated in recent years.Existing VIO methods usually consider the localization or navigation issues of robots or autonomous vehicles in relatively small areas.This paper considers the problem of vision-aided inertial navigation(VIN)for aircrafts equipped with a strapdown inertial navigation system(SINS)and a downward-viewing camera.This is different from the traditional VIO problems in a larger working area with more precise inertial sensors.The goal is to utilize visual information to aid SINS to improve the navigation performance.In the multistate constraint Kalman filter(MSCKF)framework,we introduce an anchor frame to construct necessary models and derive corresponding Jacobians to implement a VIN filter to directly update the position in the Earth-centered Earth-fixed(ECEF)frame and the velocity and attitude in the local level frame by feature measurements.Due to its filtering-based property,the proposed method is naturally low computational demanding and is suitable for applications with high real-time requirements.Simulation and real-world data experiments demonstrate that the proposed method can considerably improve the navigation performance relative to the SINS.
