Degradation of effective carrier-power-to-noise densityratio based on code trackingspectral sensitivitycoefficient for GNSS radio frequencycompatibilityin C band

The frequency band between 5 010 MHz and 5 030 MHz allocated as C band has been used as a candidate in the global navigation satellite systems （GNSS） along with more and more naviga- tion services in L band. The potential benefits and technical requirements of C band for satellite navi- gation have been analyzed before. However the degradation of effective carrier-power-to-noise densi- ty ratio（ A （C/No ）eu） based on code tracking spectral sensitivity coefficient（ CT_SSC ） as a compati- bility assessment methodology for potential GNSS radio frequency compatibility in C-Band has not been discussed clearly. So the compatibility of the signals in the C band between BeiDou （BD） B1 C and GPS L1C, L1C/A, Galileo E1Os as the interoperability or classical signals in L band is analyzed. Simulation results reveal the interference degree between BD III B1C and GPS L1C/A, L1C, Galileo E1OS. The results can also reveal that the multiplexed binary offset carrier （MBOC） and binary phase shift keying （BPSK） modulation is not appropriate for C band.

Analysis of noncommensurate sampling effects on the performance of PN code tracking loops

Noncoherent early-late processing （NELP） code tracking loops are often implemented using digital hardware for digital global positioning system （GPS） receivers. Noncommensurate sampling technology is widely used because it is viewed as an effective solution to cope with the drawback of digital effects. However, the relationship between the sampling rate and auto-correlation function （ACF） is not adequately characterized by traditional analysis. The principles for selecting the sampling rate are still not apparent. In order to solve this problem, we first analyzed the effects of different sampling rates on ACF and obtained the analytical form of a discrete auto-correlation function （DACF） for a noncommensurate sampling rate. Based on the result, the relationship between the step variation in DACF and NELP parameters such as sampling rate, integration time, and correlator spacing was determined. The maximum step variation size of DACF was also determined. However, considering the actual situation, additional factors such as code Doppler shift, precorrelation filter, and thermal noise may degrade the step variation of DACE The relationship between the step variation and these factors was analyzed separately. An appropriate sampling rate and appropriate correlator spacing were proposed to achieve the typical accuracy of measurement. The numerical simulation verified the validity of the above theoretical analyses, and finally, the conclusions and design constraints for the digital GPS receiver are summarized.

Determination of optimal period of absolute encoders with single track cyclic gray code

Low cost and miniaturized rotary encoders are important in automatic and precise production. Presented here is a code called Single Track Cyclic Gray Code (STCGC) that is an image etched on a single circular track of a rotary encoder disk read by a group of even spread reading heads to provide a unique codeword for every angular position and features such that every two adjacent words differ in exactly one component, thus avoiding coarse error. The existing construction or combination methods are helpful but not sufficient in determining the period of the STCGC of large word length and the theoretical approach needs further development to extend the word length. Three principles, such as the seed combination, short code removal and ergodicity examination were put forward that suffice determination of the optimal period for such absolute rotary encoders using STCGC with even spread heads. The optimal periods of STCGC in 3 through 29 bit length were determined and listed.

Influence of B1 code correlation loop for vector tracking structures under complicated environment

The code tracking loop is a key component for user positioning. The pseudorange information of Bei Dou B1 signals has been fused and changed for vector tracking, so a correlation output model for complex scenarios is designed to prevent the propagation of error and valuate the signal performance. The relevant software and hardware factors that affect the output are analyzed.A single channel time-division multiplexing(TDM) method for multicorrelation data extraction is proposed. Statistical characteristics of the correlation output data for both vector and scalar structures are evaluated. Simulation results show that correlation outputs for both structures follow normal or Chi-squared distributions in normal conditions, and the Gamma distribution in harsh conditions. It is shown that a tracking model based on the multi-channel fusion hardly changes the probability distribution of the correlation output in the normal case, but it reduces the ranging error of the code loop, and hence the tracking ability of the code loop for weak signals is improved. Furthermore, vector tracking changes the pseudorange characteristics of channels anytime, and affects the mutual correlation outputs of the code loops in the abnormal case. This study provides a basis for the subsequent design of autonomous integrity algorithms for vector tracking.

面向电子航海图分发服务的多级可逆水印算法

针对电子航海图(ENC)分发过程中存在的版权归属不清、泄露责任难以认定的问题,在顾及ENC对数据扰动敏感、精度要求高特点的基础上,以高隐蔽性ENC数据多级分发版权保护为目标,提出了一种面向ENC分发服务的多级可逆水印算法。首先通过精度移位创造独立水印信息嵌入空间确保算法的可逆,其次通过控制水印信息嵌入的坐标位置减小对数据精度的干扰,然后利用极坐标转换的方式隐藏水印信息,最后基于水印信息的提取与再嵌入实现动态多级分发。实验结果表明:该算法具有较好的不可感知性和充足的水印容量,能有效实现ENC多级分发过程中的版权溯源,预防数据盗版。

二维码识别技术在手术室设备中的追踪管理及应用

目的提出基于二维码识别的手术室设备管理追踪方法,通过减少信息存储的滞后,准确追踪到手术室设备应用状态及历史记录,以提升手术室设备的使用效率。方法首先通过光电扫描仪扫描手术室设备的二维码,并将其通过互联网Web服务器传输到服务器。然后,利用超带宽法存储二维码信息数据,并利用存储的信息,实现手术室新、旧设备质量的向前追踪和向后追踪。最后,将追踪信息反馈到客户端,提供设备分析依据。结果超宽带存储方法可以减少信息存储的滞后,当数据达到450万个时,延时约为270 ms。本文方法可有效追踪每个手术室内正在应用的设备,也能够准确追踪手术室设备从采购、使用、维修、售后等过程,并对其实现记录。结论该方法不仅提升了手术室设备的使用效率,还为设备的采购、使用、维修和售后服务等全过程管理提供了详实的数据支持,有助于医疗机构优化资源配置,提高手术室运营的整体效能。

多相关器联合功率GNSS欺骗干扰检测方法研究

GNSS民用信号因其公开性和脆弱性易受外界欺骗干扰.作为欺骗干扰检测的有效方法,信号质量监测(signal quality monitoring,SQM)技术通过检测接收机跟踪环路早码、即时码、晚码(early late phase,ELP)的相关结果,与无欺骗时的相关特性对比,判断是否存在欺骗干扰.常规SQM算法仅利用ELP三个信息,检测性能受限,为此提出多相关器联合功率(SQM detection of power combined Multi-correlator groups,SPCM)算法.以ELP之间多个等间隔相关器输出功率的加权为检测量,且取相关时刻与即时码时间差的反比为加权系数;进一步分析检测量的概率分布特性,并基于Neyman-Pearson理论确定最佳检测阈值,通过比较检测量与检测阈值的大小,判断是否存在欺骗干扰.基于美国德克萨斯大学奥斯汀分校公开的场景四数据集进行试验,结果表明:与Ratio和ELP等典型SQM算法相比,在不同虚警率条件下,所提出SPCM算法兼具高检测概率和快速预警响应时间性能.

整木生产进度跟踪二维码扫描系统的设计与应用

生产进度跟踪是整木定制家具企业生产管理的重要内容。实现对生产环节各个节点进度的精确把控,通过对M家具公司的生产车间流程的调查研究,总结出整木生产进度管理具有信息化程度低、同项目齐套管理难度大、采购进度难跟踪的难点。以M家具公司作为案例进行研究,以二维码扫描技术为基础,按照“批次-订单-部件”的结构,制定了整木生产进度跟踪二维码扫描系统的技术方案,并以此为基础,设计出管理系统的功能框架。将二维码扫描系统投入使用后,通过经验总结的方法,制定各个生产环节的标准操作流程。新系统的使用,降低车间工作的透明度,能够获得生产信息的及时反馈,大大降低了生产进度管理的难度,是企业在信息化道路上迈出的重要一步。

PDCA循环结合追踪方法学在提升病案管理效率与编码精准度中的应用研究

目的探讨PDCA(Plan Do Check Act)循环结合追踪方法学在提升病案管理效率与编码精准度中的应用效果。方法选取2023年1—6月于盐城市第三人民医院病案室工作的8名工作人员及同期39000份病案资料,纳入追踪组,接受追踪方法学管理;选取2023年7—12月同一批工作人员及同期39000份病案资料,纳入联合组,在追踪组基础上接受PDCA循环管理。比较两组管理效果。结果联合组工作质量各项评分高于追踪组,差异有统计学意义(P均<0.05)。联合组病案质量各项评分高于追踪组,差异有统计学意义(P均<0.05)。联合组工作效率、编码准确率(98.00%)高于追踪组,修改率(1.52%)、错误率(0.48%)低于追踪组,差异有统计学意义(χ^(2)=486.789,313.187,170.318,P均<0.05)。结论PDCA循环结合追踪方法学在病案管理中的应用能够显著提高工作人员工作质量、工作效率以及编码精准度,优化病案管理质量。

基于ARcode的移动增强现实系统研究

为解决移动设备多用户、大数据量目标的识别和跟踪问题,提出一种基于改进二维码的新型移动增强现实系统。通过C/S框架保证模型的更新,在客户端分离出识别和渲染过程,分析基于快速响应矩阵码的跟踪注册方法,针对其存在的跟踪范围小、跟踪不稳定的问题给出解决方案,从而完善系统。实验结果表明,与基于常规标志点和利用自然特征的方法相比,该系统方便实用、便于推广,且条码容易被手机使用,能识别出更多的信息。

Efficient tracker based on sparse coding with Euclidean local structure-based constraint

Abstract:Sparse coding(SC)based visual tracking(l1-tracker)is gaining increasing attention,and many related algorithms are developed.In these algorithms,each candidate region is sparsely represented as a set of target templates.However,the structure connecting these candidate regions is usually ignored.Lu proposed an NLSSC-tracker with non-local self-similarity sparse coding to address this issue,which has a high computational cost.In this study,we propose an Euclidean local-structure constraint based sparse coding tracker with a smoothed Euclidean local structure.With this tracker,the optimization procedure is transformed to a small-scale l1-optimization problem,significantly reducing the computational cost.Extensive experimental results on visual tracking demonstrate the eectiveness and efficiency of the proposed algorithm.

基于信号集中监测系统的轨道电路码序监督方法研究

自动闭塞线路通过轨道电路向列车传递低频码来反映前方空闲闭塞分区的数量,为列车运行提供行车指令,一旦轨道电路低频码错误将产生严重的安全风险。为此研究一种通过既有信号集中监测系统(CSM)实现轨道电路低频码序监督的方法。结合CSM系统的自采集数据、ZPW-2000接口数据、列控中心接口数据、联锁接口数据等,实现相邻区段(闭塞分区)低频码码序一致性分析、区段(闭塞分区)低频码与区段占用逻辑一致性分析,以及区段低频码与前方信号机显示逻辑一致性分析等。当出现不一致时,可以及时报警提醒。同时,针对一些特殊场景进行分析并提出对应规避措施。基于“仿真测试+现场跟踪”相结合的测试验证表明,该方法准确可靠,可避免误报和漏报的发生。

ModiΡed pseudo-noise code regeneration method

A modiΡed pseudo-noise（PN） code regeneration method is proposed to improve the clock tracking accuracy without impairing the code acquisition time performance.Thus,the method can meet the requirement of high accuracy ranging measurements in short time periods demanded by radio-science missions.The tracking error variance is derived by linear analysis.For some existing PN codes,which can be acquired rapidly,the tracking error variance performance of the proposed method is about 2.6 dB better than that of the JPL scheme（originally proposed by Jet Propulsion Laboratory）,and about 1.5 dB better than that of the traditional double loop scheme.

基于二维码的移动机器人多传感器融合定位及路径跟踪研究

本文针对移动机器人运动过程中,里程计的累计误差导致机器人定位不精确的问题,提出一种基于二维码、里程计和惯性测量单元的移动机器人多传感器融合定位及路径跟踪方法,并使用阿克曼型机器人进行实验。实验证明:该方法具有可行性,能有效地消除累计误差。

面向代码审查的细粒度代码变更溯源方法

代码审查是现代软件分布式并行开发过程中的重要机制.在代码评审时,帮助代码评审者快速查看某一段源代码的演化过程,可以让评审者快速理解此段代码变更的原因和必要性,从而有效提升代码评审的效率与质量.现有工作虽然提供了一些类似的代码提交历史回溯方法及对应工具,但缺乏从历史数据中进一步提取辅助代码评审相关辅助信息的能力.为此,提出一个面向代码评审的细粒度代码变更溯源方法C2Tracker.给定一段方法(函数)级别的细粒度代码变更,C2Tracker能够自动追溯到历史开发过程中修改该段代码相关的代码提交,并在此基础上进一步挖掘其中与该段代码频繁共现修改的代码元素以及相关的变更片段,辅助代码评审者对当前代码变更的理解与决策.在10个著名开源项目的数据集下进行实验验证.实验结果表明,C2Tracker在追溯历史提交的准确率上达到97%,在挖掘频繁共现代码元素任务上的准确率达到95%,在追溯相关代码变更片段任务上的准确率达到97%;相比现有评审方式,C2Tracker在具体案例的代码评审效率和质量上均有较大提升,在绝大多数的代码评审案例中被评审者认为能提供“明显帮助”或“很大帮助”.

基于全线码序追踪的码序表自动生成方法

为增大码序表编制的适用范围,减少后期的修改与调整,采用基于ObjectARX的AutoCAD二次开发方式,设计实现了一种码序表辅助设计软件。该软件采用自定义实体方式将规范化的车站信号平面布置图、列控基础数据表,以及联锁表作为数据输入,建立面向对象模型,并构建全线拓扑关系;根据对应场景计算各进路码序,最终自动生成全线车站码序表,同时绘制简易站形示意图。实际的工程应用实例表明:该软件可精确计算出车站边界码序,并能满足高铁与普铁线路码序表编制需求,提高了码序表的生成效率与准确率,便于设计人员进行校核。

特殊场景下电码化电路设计

太原北站枢纽改造中,遇到列车接车进路上无道岔区段,列车越过防护的进路信号机后直接接入股道、当防护信号机因为某种原因发生突变时,列车冒进防护信号后进入股道接收错误的低频信号。针对列车冒进后错误接收低频信号原因进行研究。通过对常规站型常规电路及常见简化电路作用进行讨论,对冒进后车站作业流程进行分析,总结无法发送禁止码和无法切断发码通道原因。针对原因,提出优化JMJ继电器的励磁电路及优化站型两种可行的解决问题的思路,并对两种思路进行分别进行深化设计进行验证。根据现场实际情况进行比选,推荐优化JMJ继电器的励磁电路方法进行现场实施。

增强现实平视显示行人预警系统的视觉编码设计研究

目的随着影像和雷达传感器技术的发展,车载预警系统可以更快、更广和更高精度地实现对于行人的识别与追踪。相较于其他预警方式,增强现实平视显示预警(Augmented Reality Head-up Display,AR-HUD)可以为用户提供实时、准确的预警信息并降低用户因视线切换而带来的驾驶风险,具有较大的应用潜力。已有研究表明,预警信息的编码方式对预警效果影响显著,然而目前AR-HUD预警方式的设计标准尚未制定,因此,探究AR-HUD的预警编码方式对其应用具有重要意义。方法以AR-HUD行人预警为例,基于颜色、边框形状、闪烁等设计元素对预警信息进行编码设计,从眼动指标、行为指标和主观指标对各编码方式进行多模态的量化分析和评估,提出相应的设计建议。结论采用颜色编码可以显著提升编码可识别性,保持低漏报率的同时有较短的反应时,而非颜色编码利用冗余编码可以增强编码可识别性;采用形状编码会降低编码可理解性,但会减小用户对预警的漏报率;闪烁编码会增大对预警的漏报率和反应时;用户主观上认为冗余编码比单维编码有更强的警示性。研究结论可为AR-HUD的交互设计和实车应用提供相关理论支撑。

全电子联锁车站接近区段电码化发码延迟的解决方案

与继电联锁接近区段占用发码的电码化上码时间相比,全电子联锁上码时间延迟较大,影响行车效率。为缩短全电子联锁上码时间,阐述了一种全电子联锁的轨道电路模块和电码化模块间直连的网络连接解决方案。从网络结构,通信协议,耦合方式,故障分析和具体实现等方面做了详细的介绍。该方案使电码化模块可以尽快响应接近区段占用发码的命令,缩短上码时间,满足现场车站的应用需求。

SINS/GNSS深组合导航码相位故障诊断与重构算法

针对捷联惯性(SINS)/卫星(GNSS)中深组合矢量跟踪环路存在故障信号易串扰跟踪通道问题,提出一种基于SINS/GNSS深组合导航码相位故障诊断与重构算法。利用通道滤波器和融合滤波器的输出信息构建故障诊断和排除统计量,结合卡方分布检测阈值进行码相位故障检测,隔离故障后完成观测量集合重构。仿真结果表明,所提算法可有效诊断SINS/GNSS深组合导航系统中码相位的20m突变故障与1m/s慢变斜坡故障,准确排除故障通道,保障了矢量跟踪环路和定位结果的稳定,提升了系统完好性。