医院无线定位系统设计及实现

随着医院WLAN的建设与发展,如婴儿防盗,资产管理以及人员定位等基于WIFI的物联网应用正逐渐增多。在医院实际需求的基础上,结合现有的WIFI实时定位技术,提出了一套应用于医院的无线局域网(WLAN)实时定位系统,并对其基本架构和管理控制模式进行了介绍,并展望了WIFI实时定位技术的研究发展方向。     

基于脉冲频率合成超宽带信号的无线实时定位系统

超宽带信号为代表的无线实时定位系统近年来得到了广泛的发展。现有的超宽带无线实时定位系统由于宽带信号的特性需求,其架构复杂性,成本,及可靠性均居高不下,限制了无线定位系统的广泛应用。在该文提出应用脉冲频率合成超宽带技术的定位系统,通过多个不同载频的窄带脉冲信号的信号处理,达到了等效的超宽带定位效果的同时大幅降低了系统复杂度和成本。解析及仿真结果验证了本文提出方案的有效性,本文所提出的方案对于定位系统的开发具有重要的指导性意义。     

Characterising indoor positioning estimation using experimental data from an active RFID-based real-time location system

Indoor positioning has attracted much research effort due to many potential applications such as human or object tracking and inventory management. Whilst there are a number of indoor positioning techniques and algorithms developed to improve positioning estimation, there is still no systematic way to characterise the estimation. In this paper, we propose a method comprising of three characteristics to characterise indoor positioning estimation. We conducted experiments on an active radio frequency identification (RFID)-based real-time location system in different environmental conditions. We used both a human and a robot to traverse two experimental areas and collected positioning results at different fixed points along the traversal path. Using this basic positioning data, we were able to characterise positioning estimation using three characterisations: position accuracy, centroid consistency and angular distribution. We demonstrate the use of these characteristics for examining different points in a travelling path and different measurements.     

基于DSP的CAN总线与以太网互联系统研制

目前,实现由CAN总线设备构成的现场网络与由以太网构成的企业管理网络之间的信息共享已成为工业控制领域的趋势,所以本文介绍了一种基于TMS320F2812的CAN总线与以太网互联系统的设计方法,通过该系统可实现CAN总线与网的互连.本文给出了系统各组成部分的硬件及软件的设计与实现,并对互联的准确性、应用效果进行了验证和分析.控分采用TI公司的TMS320F2812,以太网接口模块控制芯片采用Reahek公司的RTL8019AS,CAN总线接口模块采用,TI公SN65HVIY230,硬件电路各模块的设计还包括存储器扩展、电源电路、复位电路、串口通信模块、JTAG仿真口模块等.本系件分三大模块:RTL8019AS驱动程序、TCP/IP协议移植、CAN通信程序.系统在测试中达到预期的效果.     

智慧医疗及医疗物联网应用概述

物联网技术以其终端可移动性、接入灵活方便、状态信息采集自动化等特点在医疗机构的应用中彻底打破了固定组网方式和各科室信息管理系统比较独立的局限性,能够更加有效地提高管理人员、医生和护士的工作效率,协调相关部门有序工作,有效提高医疗机构整体信息化水平和服务能力。物联网技术在医疗领域的应用潜力巨大,能够帮助医院实现对人、物、设备的智能化管理工作,支持医院内部医疗信息、设备信息、药品信息、人员信息、管理信息的数字化采集、处理、存储、传输、共享等,实现人、设备、物资管理可视化、数字化和自动化,提高医疗安全、临床效率、医疗质量和患者安全。     

实时定位系统技术应用与标准体系研究

介绍了实时定位系统(RTLS)的体系、技术结构、应用现状,阐述了ISO/IEC JTC1/SC31/WG5工作组制定的RTLS术语类、协议类、测试类等关键技术标准,分析了中国RTLS标准体系和相关标准制定情况,结合RTLS现状提出中国今后在RTLS标准的发展途径.     

双频无源超高频实时定位系统研究

提出一种基于双频比相的无源超高频射频识别（UHF-RFID）实时定位系统（RTLS）。与传统射频识别定位系统相比,该方法带宽小,精度高。分析了双频比相测距原理在无源RFID系统中的适用性,通过理论计算得到非理想因素对测距精度的影响,并在Simulink平台上进行建模。仿真结果表明,I-Q相对失配度小于0.08,基带信噪比为21.5 dB时,系统定位精度可小于0.5 m。     

测距误差分级的室内TOA定位算法

在室内TOA(time of arrival)定位中,严重的多径和非视距现象造成测距误差较大.如何降低测距误差对定位精度的影响是室内精确定位系统的重要挑战.首先介绍了基于RSSI的室内TOA测距误差分级模型(RSSI based indoor TOA ranging error model,RITEM),该模型根据测距过程的RSSI值大小,将测距误差划分为4个等级,且各个等级的误差区间和对应的RSSI值区间可以通过现场测试获得.将RITEM应用到定位算法中,提出一种基于误差分级的室内TOA定位算法(ranging error classification based indoor TOA localization algorithm,REC).算法根据TOA测距过程中的RSSI值和RITEM实时估计测距误差级别和误差范围,利用极大似然法求得定位区域中标签最大概率位置作为定位结果.仿真和实际测试结果显示,在实际室内环境中,REC定位算法具有较高的定位精度,且平均定位误差、定位误差均方差和90％定位误差、最大定位误差等性能明显好于Ls、CN-TOAG、Nano算法.     

Packet‐Reduced Ranging Method with Superresolution TOA Estimation Algorithm for Chirp‐Based RTLS

In this paper, a packet‐reduced ranging method using a superresolution time of arrival estimation algorithm for a chirp‐based real‐time locating system is presented. A variety of ranging methods, such as symmetric double‐sided two‐way ranging (SDS‐TWR), have been proposed to remove the time drift due to the frequency offset using extra ranging packets. Our proposed method can perform robust ranging against the frequency offset using only two ranging packets while maintaining almost the same ranging accuracy as them. To verify the effectiveness of our proposed algorithm, the error performance of our proposed ranging method is analyzed and compared with others. The total ranging performance of TWR, SDS‐TWR, and our proposed TWR are analyzed and verified through simulations in additive white Gaussian noise and multipath channels in the presence of the frequency offset.     

Location Error Analysis of an Active RFID‐Based RTLS in Multipath and AWGN Environments

In this paper, we analyze the location accuracy of real‐time locating systems (RTLSs) in multipath environments in which the RTLSs comply with the ISO/IEC 24730‐2 international standard. To analyze the location error of RTLS in multipath environments, we consider a direct path and indirect path, in which time and phase are delayed, and also white Gaussian noise is added. The location error depends strongly on both the noise level and phase difference under a low signal‐to‐noise ratio (SNR) regime, but only on the noise level under a high SNR regime. The phase difference effect can be minimized by matching it to the time delay difference at a ratio of 180 degrees per 1 chip time delay (Tc). At a relatively high SNR of 10 dB, a location error of less than 3 m is expected at any phase and time delay value of an indirect signal. At a low SNR regime, the location error range increases to 8.1 m at a 0.5 Tc, and to 7.3 m at a 1.5 Tc. However, if the correlation energy is accumulated for an 8‐bit period, the location error can be reduced to 3.9 m and 2.5 m, respectively.