多维可变跟踪门SPRT无源跟踪起始算法

本文提出了一种基于多维可变跟踪门检测的序列概率比检验(SPRT)无源跟踪起始算法。该算法基于目标的多特征信息,构造多维动态可变的跟踪门,进行自适应跟踪起始检测;然后根据序列概率比检验准则进行轨迹确认,从而实现自适应跟踪起始。计算机仿真结果验证了该算法的正确性、有效性。     

A novel white noise generator as the tracking generator for filter measurements

A novel and low-cost white noise generator using an ordinary Zener diode as the source of noise is presented. The Zener diode is driven by a stable dc current source such that the noise signal power generated by the Zener diode increases with increasing frequency under right dc current biasing. A 6-stage MMIC amplifier block was designed to increase the noise power further. Since the gain-frequency response of the amplifier block has a negative slope as the frequency increases, the positive slope of the noise power produced by the Zener diode is balanced with the negative slope of the amplifier gain. The resulting amplified noise signal appears to have almost constant power at the output of the amplifier. As a result, the designed noise generator exhibits white noise characteristics, and is used as a tracking generator to measure insertion loss of a RF/microwave filter.     

Analysis of surface degradation of epoxy nanocomposite due to tracking under AC and DC voltages

The tracking phenomenon, a carbonaceous process, in epoxy nanocomposite material has been studied under the AC and DC voltage in the present work. It was observed that the tracking is more severe under the DC voltages, especially under positive DC voltage when compared to negative DC voltage. The leakage current during the tracking studies was measured and moving average technique was used to characterize the trend of current flow. It was noticed that an increase in nanoclay content to epoxy resin shows a reduction in magnitude of leakage current flow during tracking test. It was also observed that the magnitude of leakage current is more under negative DC voltage compared with positive DC/AC voltage. The magnitude of leakage current and the tracking time shows inverse relationship as evident from the present study. A drastic reduction in contact angle was observed for the specimens subjected to tracking test. It was confirmed that surface discharges also cause permanent damage to the insulating material. The WAXD studies indicated that up to 5 wt% of nanoclay in epoxy resin resulted in exfoliated structure. The TEM studies were carried out on the nanocomposite structures. The TG-DTA results showed that a maximum degradation of epoxy resin occurs at around 300 °C. From the EPR study it is realized that, in the tracking formed zone the spin concentration is more in epoxy nanocomposites indicating that tracking as a damage generating process.     

一种改进的长时间压缩感知跟踪算法

压缩感知跟踪(CT)算法具有简单、高效、实时的优点,但是却存在着跟踪窗口尺寸不能自适应变化,无法有效处理遮挡以及跟踪失败后的目标再发现等问题.为了解决上述问题,提出了一种改进的长时间压缩感知跟踪算法.所提出的算法采用多尺度的目标外观再匹配方法,使得跟踪窗口大小能够适应目标尺寸变化.此外,通过分析滑动窗口内跟踪窗口图像的整体特征变化来判定目标是否发生遮挡.为了解决跟踪器漂移问题,采用Haar特征在线生成检测器,实现目标的再发现.实验结果表明提出的算法相比原CT算法具有更好的鲁棒性和准确性.     

Lessons from a distributed peer-to-peer smart tracker

Summary  This paper presents the software architecture and middleware for a distributed smart camera (DSC) system that performs multi-target tracking. Middleware is used to abstract away important operations from the details of network operation. The paper describes the tracking algorithms and their middleware needs, the software architecture of the tracker, and the lessons learned for the next generation of tracker.      

人体红外追踪小车的设计实现

本文设计了一种玩具小车，该小车具有追踪人体红外光的功能，能够给儿童带来欢乐，同时激发儿童的好奇心。文中给出了小车的设计方案及硬件软件设计，设计电路简易，成本低廉，可靠性高，具有实用价值。     

Tracking in multistatic passive radar systems using DAB/DVB-T illumination

A multistatic passive radar system exploits illuminators of opportunity like radio or television transmitters for target surveillance. In this paper we analyze the use of the illumination of television or radio stations broadcasting digital signals (DAB/DVB-T) from a target tracking view point. An important characteristic of this type of illuminators is the joint operation of several illuminators in a single frequency network (SFN). As a consequence it is a priori unknown which measurement belongs to which illuminator. This property expands the typical association task of associating measurements with targets by the task of associating measurements with illuminators. In this paper we present a comprehensive concept for target tracking in DAB/DVB-T networks accounting for the characteristics of this signal. The derived algorithms will be tested with respect to numerical simulations including a sensitivity study for parameter mismatch between simulations and tracking model.     

A Cartesian method for fitting the bathymetry and tracking the dynamic position of the shoreline in a three-dimensional, hydrodynamic model

This paper presents a Cartesian method for the simultaneous fitting of the bathymetry and shorelines in a three-dimensional, hydrodynamic model for free-surface flows. The model, named LESS3D (Lake & Estuarine Simulation System in Three Dimensions), solves flux-based finite difference equations in the Cartesian-coordinate system (x,y,z). It uses a bilinear bottom to fit the bottom topography and keeps track the dynamic position of the shoreline. The resulting computational cells are hybrid: interior cells are regular Cartesian grid cells with six rectangular faces, and boundary/bottom cells (at least one face is the water–solid interface) are unstructured cells whose faces are generally not rectangular. With the bilinear interpolation, the shape of a boundary/bottom cell can be determined at each time step. This allows the Cartesian coordinate model to accurately track the dynamic position of the shorelines. The method was tested with a laboratory experiment of a Tsunami runup case on a circular island. It was also tested for an estuary in Florida, USA. Both model applications demonstrated that the Cartesian method is quite robust. Because the present method does not require any coordinate transformation, it can be an attractive alternative to curvilinear grid model.     

基于电光效应的相干检测星间跟踪技术

设计了一种新颖的高灵敏度和高精度星间跟踪系统方案,该方案中的关键是利用具有线性电光效应的LiNbO₃晶体使入射光束产生圆锥形扫描,然后采用相干检测方法确定该光束的空间方位,据此调整细瞄准镜,实现星间跟踪.     

软件抗距离模糊技术在异步水声跟踪定位中的应用分析

异步水声定位系统可在目标信号发射时刻未知时对目标跟踪定位,此时发射和接收时钟存在固定时差。对于基于时延测量的长基线异步定位系统,当信号传播时延大于脉冲重复周期时,就会出现距离模糊。本文提出了在异步水声跟踪定位系统中软件抗模糊的思想,探讨了一种利用目标参考位置抗模糊的算法。从异步定位模型出发,得出等价的抗模糊准则,依据准则推导了算法及相应的参考位置取值范围,分析并克服了固定时差对算法的影响。海试结果验证了算法的可行性和有效性。