基于SIFT和仿射变换的航空器起飞图像跟踪方法

针对机场监视的需要,结合航空器起飞特征,研究了尺度不变特征变换( SIFT)算法和仿射变换模型,在对图像进行灰度图像序列处理的基础上,提出了将SIFT特征点跟踪与仿射变换相结合对航空器起飞信息识别、跟踪的方法。以滨海国际机场的一个起飞过程为例,对图像序列进行了运动目标识别和帧间特征点的匹配,验证了方法的可行性,为机场航空器的起飞跟踪方法提供参考。     

Surface movement radar data processing methods for airportsurveillance

An airport surveillance function operating on surface movement radar (SMR) images is proposed and evaluated. The main contributions presented are the statistical error models of the target centroid and attributes extracted from radar images, developed and applied to the design of its main data processing blocks. Besides a multihypothesis image-to-tracks assignment method, a tracking filter using the extracted orientation and a classification scheme based on target attributes is detailed. The error models confidence and processing methods performance are demonstrated through simulation in representative scenarios     

Application of Road Information in Ground Moving Target Tracking

A new algorithm is developed to achieve accurate state estimation in ground moving target tracking by means of using road information. It is an adaptive variable structure interacting multiple model estimator with dynamic models modification （DMM VS-IMM for short）. Firstly, road information is employed to modify the target dynamic models used by filter, including modification of state transition matrix and process noise. Secondly, road information is applied to update the model set of a VS-IMM estimator. Predicted state estimation and road information are used to locate the target in the road network on which the model set is updated and finally IMM filtering is implemented. As compared with traditional methods, the accuracy of state estimation is improved for target moving not only on a single road, but also through an intersection. Monte Carlo simulation demonstrates the efficiency and robustness of the proposed algorithm with moderate computational loads.     

一种无人机定距盘旋跟踪制导律及稳定性证明

对地面目标的定距盘旋跟踪问题是无人机（UAVs）在任务应用阶段需要面临的重要问题之一,如何在传感器信息受限的情况下完成跟踪任务是目前的研究热点。首先针对地面固定目标设计了一种仅依赖测距传感器的制导律,不再需要传统的视线角信号以及目标和无人机自身的定位信息;其次,设计了李雅普诺夫函数对该制导律的稳定性进行了严格数学证明;最后,将该制导律推广到对地面匀速和变速移动目标的跟踪制导。相比于现有制导律,所提出的制导律结构更为简洁,仅有一个设计参数,并且制导策略更为合理。仿真结果表明所提出的制导律能够实现无人机对地面固定和移动目标的稳定跟踪。     

低轨卫星对高轨卫星仅测角初轨计算方法

针对我国地面测站对高轨卫星监视能力缺乏的问题,提出一种低轨卫星对高轨卫星仅测角初轨计算方法。该算法引入天基跟踪坐标系,消除测距信息影响,建立仅测角观测方程;引入法向运动,增加摄动因素影响,建立扩展拉普拉斯动力学模型;推导分析观测模型和动力学模型的关系方程,将初轨计算问题转换为非线性方程求解问题,利用高斯全主元消去法完成方程求解。通过实战和仿真测角数据对方法进行检验,结果表明,该方法能利用仅测角数据对非合作目标进行初轨确定,精度在公里量级,可为我国地基监视系统提供补充参考。     

Methods for determining unimpeded aircraft taxiing time and evaluating airport taxiing performance

The objective of this study is to improve the methods of determining unimpeded (nom-inal) taxiing time, which is the reference time used for estimating taxiing delay, a widely accepted performance indicator of airport surface movement. After reviewing existing methods used widely by different air navigation service providers (ANSP), new methods relying on computer software and statistical tools, and econometrics regression models are proposed. Regression models are highly recommended because they require less detailed data and can serve the needs of general per-formance analysis of airport surface operations. The proposed econometrics model outperforms existing ones by introducing more explanatory variables, especially taking aircraft passing and over-passing into the considering of queue length calculation and including runway configuration, ground delay program, and weather factors. The length of the aircraft queue in the taxiway system and the interaction between queues are major contributors to long taxi-out times. The proposed method provides a consistent and more accurate method of calculating taxiing delay and it can be used for ATM-related performance analysis and international comparison.     

Data fusion for ground moving target tracking

The aim of ground surveillance is the large scale, continuous and near real time determination of a dynamical ground picture. This task comprises detection and tracking of moving single targets and convoys, mobile weapon systems, and military equipment. The sensors of choice are airborne Ground Moving Target Indicator (GMTI) radar and synthetic aperture radar (SAR). As ground target tracking often suffers from dense target situations, high clutter, and low visibility, the integration and fusion of external background information is essential for providing precise and continuous tracks. We present Multi Hypotheses techniques for tracking several targets in complex ground situations with clutter. Methods to incorporate topographic information, in particular digital road maps, are described and demonstrated.     

Tracking with classification-aided multiframe data association

In most conventional tracking systems, only the target kinematic information from, for example, a radar or sonar or an electro-optical sensor, is used in measurement-to-track association. Target class information, which is typically used in postprocessing, can also be used to improve data association to give better tracking accuracy. The use of target class information in data association can improve discrimination by yielding purer tracks and preserving their continuity. In this paper, we present the simultaneous use of target classification information and target kinematic information for target tracking. The approach presented integrates target class information into the data association process using the 2-D (one track list and one measurement list) as well as multiframe (one track list and multiple measurement lists) assignments. The multiframe association likelihood is developed to include the classification results based on the "confusion matrix" that specifies the accuracy of the target classifier. The objective is to improve association results using class information when the kinematic likelihoods are similar for different targets, i.e., there is ambiguity in using kinematic information alone. Performance comparisons with and without the use of class information in data association are presented on a ground target tracking problem. Simulation results quantify the benefits of classification-aided data association for improved target tracking, especially in the presence of association uncertainty in the kinematic measurements. Also, the benefit of 5-D (or multiframe) association versus 2-D association is investigated for different quality classifiers. The main contribution of this paper is the development of the methodology to incorporate exactly the classification information into multidimensional (multiframe) association.     

Multiple ground target tracking

For current GMTI trackers, one of the most common contextual information used is road network information. In this paper, we present our approach using the road network information in tracking ground targets and in solving some ambiguities that can arise at road intersections or following a target manoeuvre leaving the road. For this we examine the performances of an adapted algorithm for tracking manoeuvring ground targets on road and off road in a cluttered environment using the map information.     

防空导弹攻击目标的红外成像特性分析

通过结合对目标的红外成像特性研究,首先阐述了在复杂背景条件下防空导弹对目标的红外成像寻的制导的组成和原理。然后详细分析了地面杂散背景的辐射和散射特征,综合分析了军用飞机被防空导弹攻击目标的红外辐射特性。在对复杂背景辐射特征和目标红外特性分析的基础上,给出了一组典型地表光谱辐射亮度曲线和太阳对地表的全波段辐射能流(辐照度)随时间的变化曲线;绘制出了红外成像导引头在整个红外波段内的探测效能曲线。分析结果对研究防空导弹红外成像导引头如何从复杂背景中将目标的典型特征信息提取出来并进行有效识别和跟踪奠定了基础。     

A new dynamic pushback control method for reducing fuel-burn costs: Using predicted taxi-out time

Long departure-taxi-out time leads to significant airport surface congestion, fuel-burn costs, and excessive emissions of greenhouse gases. To reduce these undesirable effects, a Predicted taxi-out time-based Dynamic Pushback Control(PDPC) method is proposed. The implementation of this method requires two steps: first, the taxi-out times for aircraft are predicted by the leastsquares support-vector regression approach of which the parameters are optimized by an introduced improved Firefly algorithm. Then, a dynamic pushback control model equipped with a linear gate-hold penalty function is built, along with a proposed iterative taxiway queue-threshold optimization algorithm for solving the model. A case study with data obtained from Beijing International airport(PEK) is presented. The taxi-out time prediction model achieves predictive accuracy within 3 min and 5 min by 84.71% and 95.66%, respectively. The results of the proposed pushback method show that total operation cost and fuel-burn cost achieve a 14.0% and 21.1%reduction, respectively, as compared to the traditional K-control policy.(3) From the perspective of implementation, using PDPC policy can significantly reduce the queue length in taxiway and taxi-out time. The total operation cost and fuel-burn cost can be curtailed by 37.2% and 52.1%,respectively, as compared to the non-enforcement of any pushback control mechanism. These results show that the proposed pushback control model can reduce fuel-burn costs and airport surface congestion effectively.     

Aircraft traffic management on the airport surface using VHF datalink for CNS

Aircraft traffic management on the airport surface will require the effective utilization of communications, navigation and surveillance (CNS). This paper describes an experiment which provides a glimpse of future automation. The experiment combines precision surface radar, high-accuracy differential GPS (DGPS) position determination, automatic dependent surveillance (ADS), and ground and airborne automation systems able to intercommunicate via a VHF data link. In particular, this paper describes the air/ground communications provided by the VHF Data Link. Two classes of messages are processed: continual and ad hoc. The former include DGPS corrections, ADS messages and target data. The latter include graphical taxi clearances and hold bar set-reset information. The work described in this paper is the result of a cooperative venture among NASA, Westinghouse-Norden Systems and ARINC     

Magnetic Signal Processing & Analysis for Airfield Traffic Surveillance

This paper presents an innovative system for airport surface surveillance based on a novel magnetic sensing technology. Ferromagnetic objects such as vehicle motors, aircraft engines, and landing gears are detected through their deformation of the Earth's magnetic field. Tests have shown that although the local changes of the Earth's magnetic field are extremely small, the proposed sensing technology is able to detect them reliably. The primary objective of the proposed approach is to provide a complementary surveillance system for existing and future Advanced Surface Movement Guidance and Control Systems (A-SMGCS) at large airports or a cost-effective surveillance solution for monitoring critical areas at medium and small airports. Unaffected by weather conditions, interference and shadowing effects, the system provides reliable position, velocity, and direction information without requiring any equipment in aircraft or ground vehicles. The outcome of a comprehensive market analysis is discussed and test results under real life conditions at two airports are evaluated analytically.     

DGPS-based aircraft flight guidance/test system

The utilization of the GPS system for Aircraft Flight Guidance/Test (AFGT) is a research project in China. The paper describes the concepts and the technical realization of such a system, including three components: ground subsystem, on-board subsystem and data communication link using TDMA technique. The purpose of the proposed AFGT system is to calibrate and verify performance of an on-board radar. Therefore, it must meet the requirements of evaluation of radar performances in several areas: accuracy, coverage range, and others. The AFGT System's displays are separately: a Moving Colored Digital Map on which flight trajectories, waypoints, and heights of aircrafts are clearly marked; and a Polar Coordinate Figure on which the bearings, headings, and distances of aircrafts relative to the origin of the ground control center are shown. The AFGT may monitor and guide several aircrafts flying in the pointed airspace. It support airport surface surveillance and air traffic control at the terminal area. A real-time software package RTTEST, which includes tracking display software and on-flight test software for radar evaluation, has conducted simulation with satisfactory position accuracy     

基于Fratar模型的航班时刻需求战略预测方法

航班时刻是机场运行的基础和核心,准确预测机场的航班时刻需求,对于指导机场基础设施建设、运行模式调整等具有重要意义。在航班计划结构信息分析的基础上,构建了全国航班O-D矩阵,建立了多层级机场起降量预测模型,并以起降量预测结果为输入,利用Fratar交通分布预测模型,预测目标机场时刻需求。以杭州萧山机场为例,以2010年为基年,2014为预测年,验证了方法的准确性和可行性,并预测了2020年航班时刻需求,分析了不同运行模式下机场理论容量与航班时刻需求的匹配状况,分析结果表明,2020年萧山机场需由隔离运行模式过渡到相关进近,方能满足时刻需求。     

Beam tracking method based on reconfigurable intelligent surface for obstructed communication

This paper proposes a new reconfigurable intelligent surface based three-dimensional beam tracking method to solve the beam tracking problems for the unmanned aerial vehicle with obstacles in communication channels. The proposed beam tracking method can not only regulate the reconfigurable intelligent surfaces to achieve the beam tracking of the obstructed communications, but also optimize the transmission efficiency of the communication. Firstly, a reconfigurable intelligent surface is proposed, which can correlate the transmission signals by adjusting the phase-shift matrix. Meanwhile, a new communication channel is constructed according to the reconfigurable intelligent surface, which consists of two parts. The first one is the channel between the unmanned aerial vehicle and the reconfigurable intelligent surface, the other is the channel between the reconfigurable intelligent surface and the ground base station. Note that the transmission performance of the communications can be optimized by adjusting the phase shift of each uniform linear array on the reconfigurable intelligent surface. Then, a new beam tracking method for the unmanned aerial vehicle with obstructed communications is proposed on the basis of the reconfigurable intelligent surface. By proposing the mixed genetic algorithm, the estimation accuracy of the azimuth and elevation angles is improved to enhance the performance of the beam tracking. Finally, the simulations are provided to verify the effectiveness of the proposed three-dimensional beam tracking method with reconfigurable intelligent surface.     

基于机载单天线雷达一维距离数据的地表三维信息优化重建方法

陆地的刚体表面在机载雷达的任意相对运动下具有几何不变性,基于此约束可利用雷达距离像中提取出的地面多个强散射点的一维距离数据,重建出地表的三维信息以及载机未知的运动轨迹.鉴于现有基于雷达远场假设的重建方法无法适用于具有较大近场误差的地面目标重建的问题,提出一种基于雷达近场几何模型的优化重建方法,采用非线性优化方法实现了对...     

Game-theoretic modeling and control of a military air operation

An attrition-type discrete-time dynamic model is formulated for two opposing forces, labeled Blue and Red, engaged in a military air operation. The Blue force consists of combat air units and its objective is to destroy a fixed target, such as an airport or a bridge, which Is being defended by the Red force. The Red force consists of ground troops and air defense units. We model the objective functions for each side and identify the associated constraints on the control and state variables. We employ a two-level hierarchy of command and control for each force. An example scenario illustrating the implementation of this approach using concepts from non-zero sum dynamic game theory is presented     

增广误差模型算法在目标跟踪中的应用

针对目标机动运行过程中,滤波模型与机动状态模型失配的问题,提出了一种新的增广状态误差滤波模型。不同于现有增广方案,该模型从模型失配所致状态滤波误差的角度出发,将状态估计误差增广为一状态量,通过滤波估计后用其校正原状态量。算法分析表明,该增广滤波模型具有自适应调节多重渐消因子的等效特性,增强了对目标的跟踪能力。基于该增广状态误差滤波模型,给出了滤波算法设计并进行了仿真实验。实验结果表明,基于该模型的滤波算法在对机动目标进行跟踪时具有更强的鲁棒性。     

基于形态自适应网络的无人机目标跟踪方法

针对无人机影像目标跟踪过程中常出现的目标方向变化、目标遮挡变化、样本多样性不足等问题,提出了一种基于形态自适应网络的无人机航空影像目标跟踪算法。首先使用基于数据驱动的方法对数据集进行扩增,添加了遮挡样本和多旋转角度样本,提高样本多样性;提出的形态自适应网络模型通过旋转不变约束改进深度置信网络,提取强表征能力的深度特征,使得模型能够自动适应目标形态变化,利用深度特征变换算法获取待检测目标的预定位区域,采用基于Q学习算法的搜索机制对目标进行自适应精准定位,使用深度森林分类器提取跟踪目标的类别信息,得到高精度的目标跟踪结果。在多个数据集上进行了对比实验,实验结果表明该算法能够达到较高的跟踪精度,可以适应目标旋转、目标遮挡等形态变化情况,具有较好的准确性和鲁棒性。