Radar network system to observe & analyze Tokyo Bay vessel traffic

A complete grasp of the actual vessel traffic flow by accurate observation is essential to carry out vessel traffic management, design of vessel traffic route, plan of port construction, etc. Up to now, the observation of vessel traffic has needed many efforts such as the use of a special ship or car equipped with radar observation systems and the observation staff preparation for a considerably long period. In order to perform accurate observation of vessel traffic without such efforts, the authors have developed a completely automated radar network system covering the main traffic route of Tokyo Bay. In August 2003, as the second remote radar station attaching AIS equipment was set at East Ogishima (the first was installed at the National Defense Academy in 2002), the observing range could be enlarged and cover most traffic routes in Tokyo Bay. These two radars can observe the vessel traffic in Tokyo Bay simultaneously so as to know the traffic flow accurately on the basis of analyzing the integrated radar data. In addition to the development of a radar network system, the software to analyze observed vessel traffic flow has been developed. This software has various functions such as tracking of ship's position, automatic determination of ship's size, animation of ship's movements, superposition of successive radar images, display of ship's tracks, calculation of ship's speed distribution, extraction of dangerous ship encounters using subjective judgment value and bumper model, etc. Some analyzed results on vessel traffic flow observed by the remote radars in January and September 2003 are shown in this paper.     

MC-LRF based pose measurement system for shipborne aircraft automatic landing

Due to the portability and anti-interference ability, vision-based shipborne aircraft automatic landing systems have attracted the attention of researchers. In this paper, a Monocular Camera and Laser Range Finder (MC-LRF)-based pose measurement system is designed for shipborne aircraft automatic landing. First, the system represents the target ship using a set of sparse landmarks, and a two-stage model is adopted to detect landmarks on the target ship. The rough 6D pose is measured by solving a Perspective-n-Point problem. Then, once the rough pose is measured, a region-based pose refinement is used to continuously track the 6D pose in the subsequent image sequences. To address the low accuracy of monocular pose measurement in the depth direction, the designed system adopts a laser range finder to obtain an accurate range value. The measured rough pose is iteratively optimized using the accurate range measurement. Experimental results on synthetic and real images show that the system achieves robust and precise pose measurement of the target ship during automatic landing. The measurement means error is within 0.4° in rotation, and 0.2% in translation, meeting the requirements for automatic fixed-wing aircraft landing.Received 5 July 2022; revised 19 August 2022; accepted 27 September 2022.     

Recursive estimation of radar biases using electronic charts

This work describes the application of the extended Kalman filter (EKF) to the estimation of range and bearing biases in marine radars by performing a map-matching between the data from hydrographic charts and the radar images. By defining at least two corresponding points from the radar image and the electronic charts, the technique provides a rapid and accurate calibration in range and bearing, giving also estimates for the speed, heading, latitude, and longitude of the ship. The method is tested with simulated data to check convergence and later with real data obtained from a navigation console installed on a patrol boat The technique does not require GPS nor speed information from the ship log unit, however it is shown that their inclusion can improve the estimation.     

歼击轰炸机反舰作战中存在的问题及对策研究

为了进一步提高歼击轰炸机作战性能,对歼击轰炸机的发展历史及特性进行了分析,研究了反舰作战中存在的问题,提出了解决问题的协同作战方法和航路规划技术,在研究了协同作战体系结构的基础上,建立了基于MAS的协同作战决策模型,可进一步提高反舰作战能力。     

CWLFM Radar for Ship Detection and Identification

Continuous wave lineal frequency modulated (CWLFM) radar presents some interesting advantages for coast surveillance and control as well as low probability of interception (LPI). This paper presents real results obtained with a radar prototype and processed with ISAR techniques. Also, results of an automatic ship identification system applied to simulated ISAR images are exposed. Moreover, radar behavior with unfavorable meteorological conditions is discussed     

飞机整体壁板智能数控编程系统

结合飞机整体壁板结构特点、典型加工工艺路线.针对目前数控编程中存在的问题,对智能数控编程相关技术作了一定的探索.主要内容包括飞机整体壁板智能数控编程系统结构建立、数控加工知识综合表示、广义槽加工单元分层识别、基于几何特性加工刀具自动选取、基于知识推理的加工自动排序等.最后应用上述技术开发了飞机整体壁板快速数控编程系统.     

航电系统安全性分析工具设计与研究

随着航电系统综合化程度的不断提高,传统的安全性分析方法过于依赖工程经验,难以保证失效模式的完备性。同时在系统迭代设计的过程中,由于系统的复杂性,会导致安全性分析工作量过大,增加了时间及经济成本。针对上述问题,设计了一种自动化安全性分析工具,基于Sys ML描述语言建立安全性数据模型,采用路径追溯的方法完成故障树自动建模,并对生成的故障树进行共模分析和区域安全性分析。以某系统为例的实验结果表明,该工具能够实现故障树自动建模与分析,提高了安全性分析的效率和完备性。     

基于Hausdorff距离的反舰导弹目标选择方法

如何从舰艇编队中选择预定目标,是超视距反舰导弹亟待解决的一个问题。文章基于Hausdorff距离的部分匹配理论研究了这一问题。火控雷达探测到的编队信息和末制导雷达探测到的编队信息都用点集来描述,通过点集形状匹配获取这两个点集的对应点,从而实现对预定目标的选择。重点提出了一种新的部分匹配途径,能够自适应地逐个剔除引起形状不相似的外部点而同时保留两个形状的相似部分。仿真试验表明,相比以往基于编队相互位置关系的方法,论文所研究的预定目标选择方法具有更好的抗干扰能力。     

考虑杆臂效应与挠曲变形的全自动着舰技术

联合精确进近和着陆系统（JPALS）舰载组件旨在为最终进近阶段的舰载机提供自动着舰能力。针对由于舰船杆臂效应与挠曲变形的存在导致舰载机着舰定位精度下降的问题,开发了一种基于卫星引导的全自动着舰非线性化参数误差模型,结合舰船甲板运动及舰载机纵向飞行控制模型,评估舰船结构挠曲和姿态不确定性对着舰落点精度的影响。结果表明,杆臂效应与挠曲变形对着舰落点精度有显著影响,利用建立的误差模型以及飞行控制模型,能够将着舰落点精度有效控制在着舰标准之内。     

RSAB积木块自动布线系统

 本文介绍了在SUN工作站UNIX操作系统下实现的一个用于LSI/VLSI积木块布图设计的自动布线系统——RSAB,给出了系统构成,通道定义方法以及全局和通道布线算法。系统除了可对一般信号线网自动布线外,还可处理特殊线网(电源/地线网,临界线网等)的自动布线。目前RSAB已集成在一个交互式版图编辑系统——Magic中,提供设计者一个友好的用户界面和自动/交互式布图环境。实验结果表明RSAB是可行的,布线结果令人满意。     

用于无人直升机着舰控制的计算机视觉技术研究

 通过理论分析和计算机半实物仿真研究了一种应用于无人直升机自主着舰的双目立体计算机视觉系统及相关计算机视觉技术。研究了基于HSV 均匀色标的计算机视觉技术在无人直升机着舰控制中的应用。使用Hough 变换算法检测直线参数,在Hough 变换中利用梯度信息,它的应用打破了Hough 变换的计算瓶颈。整套算法的抗噪声能力很强,达到了无人直升机自主着舰的实时性和实用性要求。     

基于LADRC的舰载V/STOL飞机短距起飞性能优化

针对垂直/短距起降（V/STOL）飞机在有限的甲板上实施滑跑起飞以及离舰后快速、稳定爬升的实际需要，对其整个过程进行操控优化以提升短距起飞性能。建立了反映多推力矢量操纵特性的非线性动力学模型，其中包含了地面效应模型和V/STOL飞机特有的喷气诱导效应模型。分别以舰面滑跑距离最短和离舰后增速时间最短为优化指标，给出了舰面滑跑和离舰初期的预置多推力偏转方案。在此基础上，提出了一种线性自抗扰反演（LADRC-Backstepping）控制方法，以实现对爬升角不确定非仿射系统的有效控制，其中设计了一种辅助补偿系统来拟制控制量的饱和，同时保证了爬升角跟踪误差的有界性；直接利用一种高阶LADRC方法设计了俯仰角控制器，确保了V/STOL飞机最终以稳定的姿态爬升。仿真结果表明，所提出的"二次预置多推力偏转角+爬升角控制+俯仰角控制"的分段优化操控策略，能够较好地提升V/STOL飞机的短距起飞性能，对内部不确定性和外界干扰具有较强的鲁棒性，可满足实际飞行任务的需要。     

Measuring Aircraft Carrier Flexure in Support of Autonomous Aircraft Landings

This paper quantifies the experimental measurements of aircraft carrier flexure (deformation) at sea in support of the United States Department of Defense sea-based Joint Precision Approach and Landing System (JPALS) that aims to deliver automatic landing capabilities to inbound aircraft aboard aircraft carriers. The methodology for measuring ship flexure using the Global Positioning System (GPS) and inertial sensors is described. Results indicate that flexure on the aircraft carrier used for testing has a standard deviation of approximately 1–2 cm. For the ship tested, the most significant flexure effects are in the port/starboard direction and correlate best with roll or lateral acceleration.     

All terrain ground collision avoidance and maneuvering terrainfollowing for automated low level night attack

The development of an all-terrain ground collision avoidance system (GCAS) in conjunction with a maneuvering terrain-following (TF) system is discussed. Both systems use a digital terrain database. These systems are presented concurrently because of their complementary mission role. The unprecedented pilot interaction available with the automatic systems provides a means to improve combat survivability significantly. The pilot is able to execute high rate turns, evasive maneuvers, and inverted ridge crossings while following the terrain contour. Safety is maintained in day, night and weather by the GCAS. The combination of these systems with an automated attack system, automatic target handoff system, night vision system, and a route planner to provide a lethal night attack capability is examined. Piloted simulation and preliminary flight test results are presented     

支持单人制机组运行的机载监视应用系统

随着新一代航空运行体系要求飞机的运行更精确,驾驶舱系统和地面管制系统的工作负荷也随之增加。机载监视应用系统承担着授权的空中交通管制服务处理功能,在机内机组高负荷工作状态、失能状态下,协同飞行管理系统和（或）地面机组承担包括自主分离保证、战术航路,冲突解决和/或自动着陆、场面运行等航路运行的管理,旨在降低机组和管制员的工作负荷。为满足单人制机组运行下机组资源管理的要求,可采用智能等级的分析方法开展机载监视应用系统功能的分析和捕获工作。     

基于AutoCAD的线切割自动编程接口软件设计

在分析DXF文件格式、3B指令代码的基础上,提出了基于AutoCAD的线切割自动编程流程,并重点讨论了自动编程过程中的基本加工路线生成、间隙补偿、计数长度计算等关键技术。     

Automatic recognition of ISAR ship images

Inverse synthetic aperture radar (ISAR) produces images of ships at sea which human operators can be trained to recognize. Because ISAR uses the ship's own varying angular motions (roll, pitch, and yaw) for cross-range resolution, the viewing aspect and cross-range scale factor are continually changing on time scales of a few seconds. This and other characteristics of ISAR imaging make the problem of automatic recognition of ISAR images quite distinct from the recognition of optical images. The nature of ISAR imaging of ships, and single-frame and multiple-frame techniques for segmentation, feature extraction, and classification are described. Results are shown which illustrate a capability for automatic recognition of ISAR ship imagery     

Aeroelastic analysis of a shipboard helicopter rotor with ship motions during engagement and disengagement operations

An aeroelastic simulation of a shipboard helicopter rotor with ship motions during engagement and disengagement operations is investigated to explore the coupled dynamic behavior between the rotor and the ship. A finite element analysis based on a moderate deflection beam model is employed to capture the flap, lag and torsion deflections of the rotor blade. The ship is treated as a six-degree-of-freedom rigid body. By using the Hamilton?s principle, system equations of motion are derived based on the generalized force formulation. The responses agree well with the test data of the rotor blade droop stop impact and the transient aeroelastic response of the shipboard teetering model rotor. Parametric investigations illustrate that the ship pitch motion has significant influence on the maximum negative displacement of the blade tip. Additional over 25% increase of the tip deflection can be introduced by the ship pitch motion. The aerodynamic and inertial couplings between the ship motion and the rotor have significantly nonlinear influence on the transient aeroelastic response. Both terms should be taken into account in the coupled helicopter–ship dynamics model.     

综合导航系统信息融合模拟仿真平台设计CSCD

为解决综导系统的信息融合问题,设计了一种新型的综导系统信息融合模拟仿真研究平台。平台包括综导信息融合模拟评估导调台、惯性类导航设备模拟器、非惯性类导航设备模拟器、综合导航模拟器、电子海图系统和数据分析服务器六大模块。导调台采取一种新的船舶运动参数发生器模拟生成多种海况条件下船舶运动参数;综合导航模拟器采取多种融合算法并行运行方式,以方便比较不同算法的性能;数据分析服务器采用高性能计算机模拟公共计算环境,可研究适应未来船舶软硬件计算资源的信息融合方法。系统测试表明,基于平台的导航信息融合流程和效果满足要求,所设计的平台系统功能正常,可直接用于舰船信息融合算法的设计、分析、测试评估等工程研发工作。     

复合材料自动铺带技术研究——曲面铺带轨迹算法

为满足自动铺带成型工艺要求,在自由曲面上规划预浸带轨迹。采用三角形网格划分逼近自由曲面方法,将商业CAD软件导出曲面的表面三角化数据格式（STL）文件用于曲面分析,对网格信息重构,建立点、边、面之间的关联信息。算法中应用“自然路径”原理在曲面上规划预浸带轨迹,研究了曲面边界处轨迹计算问题,提出了过三角形顶点出现“奇异性”问题的解决方法。通过在曲面上求解预浸带轨迹,证明了该算法的可行性。