北邮果园大二物联网导论2.Sensing Technologies of IoT

1.1D Barcode

（1）定义

条形码是与所附物体相关的数据的光学机器可读表示。最初，条形码通过改变平行线的宽度和间距来表示数据，可以称为线性或一维（1D）。A barcode is an optical machine-readable representation of data relating to the object to which it is attached. Originally barcodes represent data by varying the widths and spacings of parallel lines, and may be referred to as linear or one-dimensional (1D).

（2）工作原理How does a barcode work

①每个字符都由一个宽条和窄条的图案表示。条形码读取器使用光电传感器在条形码移动时将条形码转换为电信号。然后，扫描仪测量条形和空格的相对宽度，将不同的图案转换回常规字符，并将其发送到计算机或便携式终端。Each character is represented by a pattern of wide and narrow bars. A barcode reader uses a photosensor to convert the barcode into an electrical signal as it moves across a barcode.The scanner then measures the relative widths of the bars and spaces,translates the different patterns back into regular characters, and sends them on to a computer or portable terminal.

②每个条形码都以特殊的开始字符开始，并以特殊的停止字符结束。这些代码有助于读者检测条形码，并确定条形码是向前扫描还是向后扫描。Every barcode begins with a special start character and ends with a special stop character. These codes help the reader detect the barcode and figure out whether it is being scanned forward or backward.

③某些条形码可能在停止字符之前包含校验和字符。使用条形码中的字符打印条形码时计算校验和。读取器执行相同的计算，并将其答案与条形码末尾读取的校验和进行比较。如果两者不匹配，则读者认为有问题，抛出数据，然后重试。Some barcodes may include a checksum character just before the stop character. A checksum is calculated when the barcode is printed using the characters in the barcode. The reader performs the same calculation and compares its answer to the checksum it read at the end of the barcode. If the two don't match, the reader assumes that something is wrong, throws out the data, and tries again.

（3）例子

①The Universal Product Code (UPC)

一种条形码符号（即特定类型的条形码），在北美以及英国、澳大利亚和新西兰等国家广泛使用，用于跟踪商店中的商品。其最常见的形式UPC-A由12个数字组成，这些数字被唯一地分配给每个贸易项目。 is a barcode symbology (i.e., a specific type of barcode), that is widely used in North America, and in countries including the UK, Australia, and New Zealand for tracking trade items in stores. Its most common form, the UPC-A, consists of 12 numerical digits, which are uniquely assigned to each trade item. UPC-A用于标记在美国零售的产品。条形码识别制造商和特定产品，因此销售点收银系统可以自动查找价格。UPC-A代码和制造商ID号的分配在美国由统一代码委员会控制。UPC-A is used for marking products which are sold at retail in the USA. The barcode identifies the manufacturer and specific product so point-of-sale cash register systems can automatically look up the price. The UPC-A Code and the assignment of manufacturer ID numbers is controlled in the U.S.A. by the Uniform Code Council. UPC-E 是UPC-A符号的变体。通过抑制零，UPC-E代码可以在非常小的空间内打印，并用于标记小项目。is a variation of the UPC-A symbol. By suppressing zeroes, UPC-E codes can be printed in a very small space and are used for labeling small items. 压缩的工作原理是从条形码中挤出多余的零，然后自动将它们重新插入扫描仪。只有包含零的条形码才是UPC-E符号的候选条形码。统一代码委员会在分发带有额外零的制造商ID号时非常吝啬；这些是为真正需要UPC-E符号的产品保留的。Compression works by squeezing extra zeroes out of the barcode and then automatically re-inserting them at the scanner.Only barcodes containing zeroes are candidates for the UPC-E symbol.The Uniform Code Council is very stingy when it comes to handing out manufacturer ID numbers with extra zeroes;these are reserved for products which have a genuine need for the UPC-E symbol.

②Codabar

是1972年开发的一种线性条形码符号。Codabar可以对数字0到9、六个符号（-：.$/+）和开始/停止字符a、B、C、D、E、*、N或T进行编码。开始/停止符号必须成对使用，并且不能出现在条形码的其他位置。Codabar用于图书馆、血库、隔夜包裹递送行业以及各种其他信息处理应用。is a linear barcode symbology developed in 1972. Codabar can encode the digits 0 through 9, six symbols (-:.$/+), and the start/stop characters A, B, C, D, E, *, N, or T. The start/stop characters must be used in matching pairs and may not appear elsewhere in the barcode. Codabar is used in libraries, blood banks, the overnight package delivery industry, and a variety of other information processing applications.

③EAN-13 (European Article Number)在全球范围内用于标记零售商品。该符号编码13个字符：前两个或三个是国家代码，用于识别制造商注册的国家（不一定是产品实际生产的国家）。国家/地区代码后跟9或10个数据位（取决于国家/地区码的长度）和一个位数的校验和。is used world-wide for marking retail goods. The symbol encodes 13 characters: the first two or three are a country code which identify the country in which the manufacturer is registered (not necessarily where the product is actually made).The country code is followed by 9 or 10 data digits (depending on the length of the country code) and a single digit checksum.

④Interleaved 2 of 5 (Code 25, I2of5, ITF, I25)这是一种在仓库和工业应用中广泛使用的纯数字条形码。数据必须由偶数位数组成。is a numeric-only barcode widely used in warehouse and industrial applications. The data must consist of an even number of digits. 每个数据字符由5个元素组成，5个条形或5个空格。在这5个元素中，两个元素是宽的，三个元素是窄的。相邻字符是交错的，将一个字符的空格与另一个字符中的空格交替。Each data character is composed of 5 elements, either 5 bars or 5 spaces. Of these 5 elements, two are wide and three are narrow. Adjacent characters are interleaved,alternating the spaces from one character with the bars of the other. ⑤Code 39 是一种可变长度的离散条形码符号。Code 39规范定义了43个字符，包括大写字母（A到Z）、数字（0到9）和一些特殊字符（-、.、$、/、+、%和空格）。代码39广泛用于许多行业，是许多政府条形码规范的标准，包括美国国防部。is a variable length,discrete barcode symbology.The Code 39 specification defines 43 characters,consisting of uppercase letters (A through Z), numeric digits (0 through 9) and a number of special characters (-, ., $, /, +, %, and space). Code 39 is widely used in many industries and is the standard for many government barcode specifications,including the U.S.Department of Defense.

⑥Code 93 是Code 39的更紧凑版本。它编码与Code 39完全相同的字符，但每个字符使用9个条形码元素，而不是15个。is a more compact version of Code 39. It encodes exactly the same characters as Code 39, but uses 9 barcode elements per character instead of 15.

⑦Code 128为所有数字数据提供优异的密度，为字母数字数据提供良好的密度。在新的应用程序中，由于其密度和提供了更大的字符选择，它通常被选为代码39。代码128标准由AIM（自动识别制造商）维护。代码128字符集包括数字0-9、字母A-Z（大写和小写）以及所有标准ASCII符号和控制代码。provides excellent density for all-numeric data and good density for alphanumeric data. It is often selected over Code 39 in new applications because of its density and because it offers a much larger selection of characters. The Code 128 standard is maintained by AIM (Automatic Identification Manufacturers). The Code 128 character set includes the digits 0-9, the letters A-Z (upper and lower case), and all standard ASCII symbols and control codes.

⑧Bookland EAN (for ISBN numbers)在国际上用于识别书籍以及视频和音频磁带和软件。分配给每个项目的唯一编号是国际标准书号（ISBN）。is used internationally to identify books as well as video and audio cassettes and software. The unique number assigned to each item is the International Standard Book Number (ISBN).

如果ISBN在2007年1月1日之后分配，则其长度为13位，如果在2007年之前分配，则ISBN长度为10位。国际标准书号由4或5部分组成：

The ISBN is 13 digits long if assigned after January 1,2007,and 10 digits long if assigned before 2007. An International Standard Book Number consists of 4 or 5 parts:

对于13位ISBN，前缀：978或979（表示行业；在本例中，978表示图书出版）、组标识符（语言共享国家组）、出版商代码（2-5位）、项目编号（书名）以及校验和字符或校验数字。 for a 13-digit ISBN, a prefix: 978 or 979 (indicating the industry; in this case, 978 denotes book publishing)、the group identifier, (language-sharing country group)、the publisher code (2-5 digits)、the item number (title of the book), and A checksum character or check dight.

（4）Barcode reader

①定义：A barcode reader (or barcode scanner)是用于读取打印条形码的电子设备。像平板扫描仪一样，它由光源、透镜和将光脉冲转换为电脉冲的光传感器组成。此外几乎所有条形码读取器都包含解码器电路用于分析传感器提供的条形码图像数据并将条形码内容发送到扫描仪的输出端口。is an electronic device for reading printed barcodes.Like a flatbed scanner, it consists of a light source,a lens and a light sensor translating optical impulses into electrical ones.Additionally,nearly all barcode readers contain decoder circuitry analyzing the barcode's image data provided by the sensor and sending the barcode's content to the scanner's output port. ②分类Technology types of barcode reader Pen-type readers: 笔式读卡器由一个光源和光电二极管组成，它们在笔或杖的尖端彼此相邻放置Pen-type readers consist of a light source and photodiode that are placed next to each other in the tip of a pen or wand. Laser scanners: 激光扫描仪的工作方式与笔式阅读器相同，不同之处在于它们使用激光束作为光源，通常使用往复反射镜或旋转棱镜来来回扫描激光束。Laser scanners work the same way as pen type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the aser beam back and forth across the bar code. CCD readers:CCD读取器使用数百个微小的光传感器阵列，在读取器的头部排成一排。CCD readers use an array of hundreds of tiny light sensors lined up in a row in the head of the reader.

Camera-based readers: 二维成像扫描仪是第四种也是最新型的条形码阅读器。他们使用照相机和图像处理技术来解码条形码。Two-dimensional imaging scanners are the fourth and newest type of barcode reader. They use a camera and image processing techniques to decode the bar code.

Omni-directional barcode scanners: “全方位”条形码扫描仪的工作原理与激光条形码扫描仪一样，添加了多个反射镜和其他反射装置，可将一条激光线转换为多条激光线，所有激光线的角度都不同。这允许在任何角度快速读取条形码，使全方位条形码扫描仪非常适合于销售点安装，例如在杂货店。An "Omni-directional" Barcode Scanner works just like a Laser Barcode Scanner with the addition of several mirrors and other reflective devices to transform one laser line into many, all at different angles. This allows fast reading of barcodes at any angle, making an Omni-directional Barcode Scanner perfect for point of sale installations, such as at a grocery store.

（5）Barcode system

条形码系统生成并解码具有视觉意义的条形码。条形码系统包括编码模块，用于接收消息和标识。还提供了一种解码模块，用于接收在典型文档处理通道中（例如，通过打印、扫描或复制过程）可能已经降级的视觉有效条形码的获取版本，并用于恢复由视觉有效条形码指定的消息。A barcode system generates and decodes a barcode with visual significance. The barcode system includes an encoding module for receiving a message and a logo and generating a visually significant barcode based on these inputs. A decoding module is also provided for receiving an acquired version of a visually significant barcode that may have been degraded in a typical document handling channel (e.g., through the printing, scanning, or copying process) and for recovering the message specified by the visually significant barcode.

2.Two-dimensional code

（1）二维符号通常是二维编码数据的正方形或矩形图案。2-Dimensional symbols are generally square or rectangular patterns that encode data in two dimensions.

（2）（对比一维条形码）

二维码的主要优点是能够在小空间中编码大量信息。标准条形码的实际限制取决于许多因素，只有20到25个字符是近似最大值；2-D符号可以编码100到大约2000个字符。The primary advantage of 2-D codes is the ability to encode a lot of information in a small space. The practical limit for a standard barcode depends on a number of factors, but 20 to 25 characters is an approximate maximum; 2-D symbols can encode from 100 to about 2,000 characters.

（3）例子

①PDF-417 （Portable Data File）PDF-417是一种二维条形码，每个符号最多可存储1800个可打印ASCII字符或1100个二进制字符。符号为矩形；通过设置宽度并允许高度随数据增长，可以在一定程度上调整符号的形状。还可以将大量数据分解为逻辑链接的几个PDF-417符号。对于可以存储在一组PDF-417符号中的数据量没有理论限制。PDF-417符号需要二维扫描仪；或标准CCD或激光扫描仪和特殊解码软件。PDF-417 is a two-dimensional barcode which can store up to about 1,800 printable ASCII characters or 1,100 binary characters per symbol. The symbol is rectangular; the shape of the symbol can be adjusted to some extent by setting the width and allowing the height to grow with the data. It is also possible to break large amounts of data into several PDF-417 symbols which are logically linked. There is no theoretical limit on the amount of data that can be stored in a group of PDF-417 symbols. PDF-417 symbols require a 2-D scanner; or a standard CCD or laser scanner and special decoding software.

②DataMatrix是一种二维条形码，可存储1至约2000个字符。符号为方形，范围从每边0.001英寸到每边14英寸。作为密度的一个例子，使用24针点阵打印机可以将500个纯数字字符编码为1英寸正方形。is a two-dimensional barcode which can store from 1 to about 2,000 characters. The symbol is square and can range from 0.001 inch per side up to 14 inches per side. As an example of density, 500 numeric only characters can be encoded in a 1-inch square using a 24-pin dot matrix printer.

DataMatrix用于编码电气铭牌上的产品和序列号信息；日本外科器械的标识；在制造过程中识别透镜、电路板和其他物品。is being used to encode product and serial number information on electrical rating plates; to mark of surgical instruments in Japan; to identify lenses, circuit boards, and other items during manufacturing.

DataMatrix symbols需要二维扫描仪。市场上有许多扫描仪同时使用激光和CCD相机技术。DataMatrix符号可以使用市场上最专业的热转印标签打印机打印。require a 2-D scanner. A number of scanners are on the market using both laser and CCD camera technologies. DataMatrix symbols can be printed using most professional-grade thermal transfer label printers on the market.

③QR Code (Quick Response Code)是一种矩阵条形码（或二维码）的商标，最初是为汽车行业设计的。最近，由于与标准UPC条形码相比，该系统具有快速的可读性和较大的存储容量，因此该系统在行业外变得流行。代码由黑色模块（方形点）组成，在白色背景上以方形图案排列。 is the trademark for a type of matrix barcode (or two- dimensional code) first designed for the automotive industry. More recently, the system has become popular outside the industry due to its fast readability and large storage capacity compared to standard UPC barcode. The code consists of black modules (square dots) arranged in a square pattern on a white background.

历史：Invented in Japan by the Toyota subsidiary Denso Wave in 1994 to track vehicles during the manufacturing process, the QR Code is one of the most popular types of two-dimensional barcodes.It was designed to allow its contents to be decoded at high speed.

与旧的条形码不同，该条形码设计为通过窄光束进行机械扫描，QR码由半导体图像传感器检测为二维数字图像，然后由编程处理器进行数字分析。处理器在图像的角落定位三个不同的正方形，并借助第四个角落附近的较小正方形来规范图像大小、方向和视角。然后将小点转换为二进制数，并用纠错码检查其有效性。Unlike the old barcode that was designed to be mechanically scanned by a narrow beam of light, the QR code is detected as a 2-dimensional digital image by a semiconductor image sensor and is then digitally analyzed by a programmed processor. The processor locates the three distinctive squares at the corners of the image, and normalizes image size, orientation, and angle of viewing, with the aid of a smaller square near the fourth corner. The small dots are then converted to binary numbers and validity checked with an error-correcting code.

3.IC card

（1）定义

智能卡、芯片卡或集成电路卡（ICC）是任何带有嵌入式集成电路的袖珍卡。智能卡可以提供识别、身份验证、数据存储和应用程序处理。A smart card, chip card, or integrated circuit card (ICC) is any pocket-sized card with embedded integrated circuits. Smart cards can provide identification, authentication, data storage and application processing.

（2）Contact smart cards 接触式智能卡

的接触面积约为1平方厘米（0.16平方英寸），包括几个镀金接触垫。这些衬垫在插入读取器时提供电连接，读取器用作智能卡与主机（例如，计算机、销售点终端）或移动电话之间的通信介质。卡不含电池；电源由读卡器提供。have a contact area of approximately 1 square centimetre (0.16 sq in), comprising several gold-plated contact pads. These pads provide electrical connectivity when inserted into a reader, which is used as a communications medium between the smart card and a host (e.g., a computer, a point of sale terminal) or a mobile telephone.Cards do not contain batteries; power is supplied by the card reader.

（3）Contactless smart card 非接触式智能卡

其中，卡通过RF感应技术与读取器通信并由读取器供电（数据速率为106–848 kbit/s）。这些卡只需要靠近天线进行通信。与带触点的智能卡一样，非接触式卡没有内部电源。相反，他们使用一个电感器来捕获一些入射的射频询问信号，对其进行整流，并用它为卡的电子设备供电。in which the card communicates with and is powered by the reader through RF induction technology (at data rates of 106–848 kbit/s). These cards require only proximity to an antenna to communicate. Like smart cards with contacts, contactless cards do not have an internal power source. Instead, they use an inductor to capture some of the incident radio-frequency interrogation signal, rectify it,and use it to power the card's electronics.

非接触式智能卡是任何带有嵌入式集成电路的袖珍卡，可以处理和存储数据，并通过无线电波与终端通信。A contactless smart card is any pocket-sized card with embedded integrated circuits that can process and store data, and communicate with a terminal via radio waves.

非接触式智能卡不包含普通的只读RFID，但它们包含可通过无线电波转录的可重写智能卡微芯片。Contactless smart cards do not contain an ordinary read-only RFID, but they do contain a re-writeable smart card microchip that can be transcribed via radio waves.

非接触式智能卡可用于识别、身份验证和数据存储。它们还提供了一种以灵活、安全、标准的方式进行业务交易的方法，而无需人工干预。Contactless smart cards can be used for identification, authentication, and data storage. They also provide a means of effecting business transactions in a flexible, secure, standard way with minimal human intervention.

（4）应用

①经济上：智能卡用作信用卡或ATM卡、燃料卡、移动电话SIM卡、付费电视授权卡、家用公用事业预付卡、高安全识别卡和门禁卡，以及公共交通和公共电话支付卡。Smart cards serve as credit or ATM cards, fuel cards, mobile phone SIMs, authorization cards for pay television, household utility pre-payment cards, high-security identification and access-control cards, and public transport and public phone payment cards.

②识别：

数字识别是一个快速增长的应用。在该应用程序中，卡验证身份。A quickly growing application is in digital identification. In this application, the cards authenticate identity.

智能卡可用于驾驶执照系统。The smart card can be used in driver‘s license system.

智能卡和综合票务已被世界各地的公共交通运营商广泛使用。Smart cards and integrated ticketing have become widely used by public transit operators around the world.

智能卡正在向学校和大学的学生提供Smart cards are being provided to students at schools and colleges

a.跟踪学生出勤Tracking student attendance

b.作为电子钱包，支付食堂的物品，自动售货机等As an electronic purse, to pay for items at canteens, vending machines etc.

  c.跟踪和监控食堂的食物选择,帮助学生保持健康的饮食Tracking and monitoring food choices at the canteen, to help the student maintain a healthy diet

  d.跟踪学校图书馆的借书Tracking loans from the school library

③医疗健康：智能健康卡可以提高患者信息的安全性和隐私性，为便携式医疗记录提供安全载体，减少医疗保健欺诈，支持便携式医疗记录的新流程，提供对紧急医疗信息的安全访问，实现对政府倡议和授权的遵守，并提供平台以实现卫生保健组织所需的其他应用。Smart health cards can improve the security and privacy of patient information, provide a secure carrier for portable medical records, reduce health care fraud, support new processes for portable medical records, provide secure access to emergency medical information, enable compliance with government initiatives and mandates, and provide the platform to implement other applications as needed by the health care organization.

4.RFID

（1）历史

  First use of RFID device – 2nd world war – Allies used RFID-like technology for Identify- Friend or Foe

  Harry Stockman October 1948 Paper – Communication by means of reflected power ( The proceedings of the Institute of Radio Engineers)

  First RFID Patent - 1973

  Auto-ID center founded at MIT – 1999

  Standardization effort taken over by EPC Global (Electronic Product Code)

  Current thrust primarily driven by Wal-Mart and DoD    Automate Distribution:

      • Reduce cost (man power, shipping mistakes)

      • Increase sales (keep shelves full)

      • DoD Total Asset Visibility Initiative

（2）定义

射频识别是使用无线非接触系统，该系统使用射频电磁场从附着在物体上的标签传输数据，以实现自动识别和跟踪。Radio-frequency identification is the use of a wireless non-contact system that uses radio-frequency electromagnetic fields to transfer data from a tag attached to an object, for the purposes of automatic identification and tracking.

（3）ADC (Automated Data Collection) technology:

使用射频波在读取器和可移动物品之间传输数据，以识别、分类和跟踪。uses radio-frequency waves to transfer data between a reader and a movable item to identify, categorize, track.

速度快，不需要读取器/扫描仪与标记物品之间的物理视线或接触。Is fast and does not require physical sight or contact between reader/scanner and the tagged item.

使用低成本组件执行操作。Performs the operation using low cost components.

尝试提供独特的标识和后端集成，以允许广泛的应用程序。Attempts to provide unique identification and backend integration that allows for wide range of applications.

Other ADC technologies: Barcodes, OCR

（4）RFID tags

有些标签不需要电池，由读取它们的电磁场供电。其他的使用本地电源并发射无线电波。标签包含电子存储的信息，可以在几米（码）外读取。与条形码不同，标签不需要在读取器的视线范围内，并且可以嵌入被跟踪对象中。Some tags require no battery and are powered by the electromagnetic fields used to read them. Others use a local power source and emit radio waves.The tag contains electronically stored information which can be read from up to several meters (yards) away.Unlike a bar code,the tag does not need to be within line of sight of the reader and may be embedded in the tracked object.

标记可以是只读或读写的Tags can be read-only or read-write

标签可以贴在几乎任何东西上Tags can be attached to almost anything: pallets or cases of product、vehicles、company assets or personnel、items such as apparel,luggage,laundry、people,livestock,or pets、high value electronics such as computers,TVs,camcorders

（5）tags的种类

①Passive被动的

从读取器辐射功率中回收的操作功率Operational power scavenged from reader radiated power

标签反映来自读取器的无线电信号Tag reflects radio signal from reader

读卡器供电Reader powered

读取范围更短Shorter Read Range

②Semi-active半主动的

电池提供的工作功率Operational power provided by battery

③Active主动的

内置在标签中的电池发射器提供的工作功率Operational power provided by battery-transmitter built into tag

标签发送无线电信号Tag transmits radio signal

电池供电的存储器、收音机和电路Battery powered memory, radio & circuitry

高读取范围High Read Range

（6）依据存储改写分类RFID tag memory

①Read-only tags

标签ID在制造期间在工厂分配Tag ID is assigned at the factory during manufacturing

• 永远无法更改Can never be changed

• 无法为标签分配额外数据No additional data can be assigned to the tag

②Write once, read many (WORM) tags

一次写入的数据，例如，在包装或制造过程中Data written once, e.g., during packing or manufacturing

• 写入数据后，标签被锁定Tag is locked once data is written

• 类似于CD或DVDSimilar to a compact disc or DVD

③Read/Write

标签数据可以随时间变化Tag data can be changed over time

•可以锁定部分或全部数据段Part or all of the data section can be locked

（7）RFID Readers：

①功能: 远程给标签供电Remotely power tags；建立双向数据链路Establish a bidirectional data link；库存标签，筛选结果Inventory tags, filter results；与网络服务器通信Communicate with networked server(s)；每秒可读取100-300个标签Can read 100-300 tags per second

②读取器（询问器）可以位于固定点，例如入口/出口，销售点，仓库Readers (interrogators) can be at a fixed point such as Entrance/exit，Point of sale，Warehouse

③读卡器也可以是移动/手持的Readers can also be mobile/hand-held

（8）Frequencies of operation

Low-Frequency (LF) 30–300kHz High-Frequency (HF) 3-30 MHz Ultra High Frequency (UHF) 300 MHz–1GHz Microwave 2–30 GHz

①Low-Frequency (LF) 30–300kHz kHz (125 kHz & 134 kHz )

Advantages

相对不受监管限制Relative freedom from regulatory limitations

非常适合需要以低速和最小距离读取少量数据的应用Well suited for applications requiring reading small amounts of data at slow speeds and minimal distances

渗透材料（水、纸巾、木材、铝）Penetrates materials well (water, tissue, wood, aluminum)

Disadvantages

不会穿透或传播金属（铁、钢）Does not penetrate or transmit around metals (iron, steel)

仅处理少量数据Handles only small amounts of data

读取速度慢Slow read speeds

大型天线——与较高频率相比Large antennas -- compared to higher frequencies

最小范围Minimal range

标签结构Tag construction:

  较厚（大于13.56 MHz）is thicker (than 13.56 MHz)

  比13.56 MHz更贵is more expensive (than 13.56 MHz)

  更复杂（需要更多的感应线圈匝数）more complex (requires more turns of the induction coil)

②High-Frequency (HF) 3-30 MHz (13.56 MHz)

Advantages

非常适合需要读取少量数据和最小距离的应用Well suited for applications requiring reading small amounts of data and minimal distances

渗透水/组织良好Penetrates water/tissue well

天线设计更简单（线圈匝数更少）；降低建造成本Simpler antenna design (fewer turns of the coil); lower costs to build

更高的数据速率（高于125 kHz，但低于更高MHz系统）Higher data rate (than 125 kHz--but slower than higher MHz systems)

更薄的标签结构（大于125 kHz）Thinner tag construction (than 125 kHz)

流行智能卡频率Popular Smart Card frequency

Disadvantages

政府监管频率（美国和欧洲最近进行了协调）Government regulated frequency (U.S. and Europe recently harmonized)

不穿透或传播金属周围Does not penetrate or transmit around metals

大型天线（与较高频率相比）Large antennas (compared to higher frequencies)

标签尺寸大于较高频率Larger tag size than higher frequencies

读数范围为≈ 0.7米Reading range of ≈ 0.7 m

③Ultra High Frequency (UHF) 300 MHz–1GHz

Advantages

金属周围有效Effective around metals

距离>1m的最佳可用频率Best available frequency for distances of >1m

标签尺寸小于13.56 MHzTag size smaller than 13.56 MHz

较小的天线Smaller antennas

高数据速率；大量数据High data rate; Large amounts of data

受控读取区（通过天线方向性）Controlled read zone (through antenna directionality)

Disadvantages

不渗透水/组织Does not penetrate water/tissue

监管问题Regulatory issues

监管问题（欧洲，950-956 MHz，日本正在研究中）Regulatory issues in (Europe, 950 - 956 MHz under study in Japan)

监管问题（欧洲，950-956 MHz，日本正在研究中）Regulatory issues in (Europe, 950 - 956 MHz under study in Japan)

④Microwave 2–30 GHz (2.45 GHz)

Advantages

标签尺寸小于感应或较低范围UHF（1“x 1/4”）Tag size smaller than inductive or lower range UHF (1"x 1/4")

更大范围Greater range

比低频UHF更高的带宽（更多的频率可跳）More bandwidth than lower range UHF (more frequencies to hop)

比低范围UHF或电感天线更小Smaller antennas than lower range UHF or inductive

高数据速率High data rate

可以比低频率更快地传输大量数据Can transmit large amounts of data more quickly than lower frequencies

受控读取区（通过天线方向性）Controlled read zone (through antenna directionality)

通过调整/设计调整，有效应对金属Effective around metals with tuning/design adaptations

Disadvantages

比较低UHF频段更易受电子噪声影响，例如433 MHz、860-930 MHzMore susceptible to electronic noise than lower UHF bands, e.g. 433 MHz, 860-930 MHz

与其他技术共享频谱——微波炉、WLANS、电视设备等。Shared spectrum with other technologies-- microwave ovens, WLANS, TV devices, etc.

要求无干扰Requires non-interfering

竞争要求：单片——技术含量高；供应商数量有限Competitive requirement: single chip--highly technical; limited number of vendors

监管审批仍在进行中Regulatory approvals still "in process

（9）RFID communications

主机管理读卡器并发出命令Host manages Reader(s) and issues Commands

§读取器和标签通过射频信号通信 Reader and tag communicate via RF signal

§读取器生成的载波信号 Carrier signal generated by the reader

§通过天线发送的载波信号 Carrier signal sent out through the antennas

§载波信号命中标签 Carrier signal hits tag(s)

§标签接收和修改载波信号–“发回”调制信号Tag receives and modifies carrier signal – “sends back” modulated signal

§天线接收调制信号并将其发送至读取器 Antennas receive the modulated signal and send them to the Reader

§读取器对数据进行解码 Reader decodes the data

§返回给主机应用程序的结果 Results returned to the host application

（10）Electronic Product Code

电子产品代码（EPC）被设计为一种通用标识符，它为世界上任何地方的所有物理对象提供了一个唯一的标识。The Electronic Product Code (EPC) is designed as a universal identifier that provides a unique identity for every physical object anywhere in the world, for all time.

电子产品代码（EPC）旨在存储在RFID标签上，是识别供应链中特定项目的唯一编号。Designed to be stored on an RFID tag, the Electronic Product Code (EPC) is a unique number that identifies a specific item in the supply chain.

其结构在EPCglobal Tag Data Standard中定义，该标准是一个开放标准，可从EPCglocal Inc.的网站免费下载。Its structure is defined in the EPCglobal Tag Data Standard, which is an open standard freely available for download from the website of EPCglobal Inc.

（11）The EPC Network

EPCglobal网络是一个用于在贸易伙伴之间共享产品数据的计算机网络。它由EPCglobal创建。网络中信息流的基础是存储在RFID标签上的每个产品的电子产品代码（EPC）。The EPCglobal Network is a computer network used to share product data between trading partners. It was created by EPCglobal. Basis for the information flow in the network is the Electronic Product Code (EPC) of each product which is stored on an RFID tag.

网络管理特定于单个产品变量的动态信息。这包括产品整个生命周期中物体运动的相关数据。The network manages dynamic information that is specific to variable for individual products. This includes data regarding the movement of an object throughout the product life cycle.

如果该系统被广泛采用，可以消除数据收集中的人为错误，减少库存，保持产品库存，减少损失和浪费，提高安全性。The system, if widely adopted, could eliminate human error from data collection, reduce inventories, keep products in stock, reduce loss and waste, and improve safety and security.

EPC全球网络由以下组件组成：对象命名服务（ONS）、EPC发现服务、EPC信息服务（EPCIS）The EPCglobal Network consists of the following components: Object Naming Service (ONS)、EPC Discovery Services、EPC Information Services (EPCIS)

ONS对象命名服务

是一种能够在EPC基础上发现对象信息的服务。使用电子产品代码，在数据库中搜索匹配的URL或IP地址，并在找到时将其发送回请求者。在URL下，可以找到与EPC相关联的对象的进一步信息。ONS与互联网中用于将名称转换为IP地址的域名系统相当。ONS是发现服务的一个实例。The ONS is a service that enables the discovery of object information on the basis of an EPC. With the Electronic Product Code a matched URL or IP-address is searched within a database and sent back to the requester when found. Under the URL further information about the object which is associated with the EPC can be found. The ONS is comparable to the Domain Name System which is used in the Internet to translate names into IP addresses. The ONS is an instantiation of Discovery Services.

发现服务

是在网络中查找EPC信息服务的工具。它们可以比作互联网的搜索引擎。它们为贸易伙伴提供了找到拥有给定产品的所有各方并共享该产品的RFID事件的能力。The Discovery Services are an instrument to find EPC Information Services within the network. They can be compared to search engines of the Internet. They offer trading partners the ability to find all parties who had possession of a given product and to share RFID events about that product.

（EPCIS）

是一个旨在实现企业内部和企业之间EPC相关数据共享的标准。这种数据共享旨在使所有网络参与者都能共同查看对象信息。在EPCIS中，每个公司都被指定有权访问其动态信息。The (EPCIS) is a standard designed to enable EPC-related data sharing within and across enterprises. This data sharing is aimed to enable all network participants a common view of object information. At the EPCIS each company designated who has access to its dynamic information.

1.当制造商标记产品时，EPC生命周期开始 EPC lifecycle begins when a Manufacturer tags the product

2. 制造商记录产品信息（例如位置）转换为EPC信息服务Manufacturer records product information (e.g., manufacture date, expiration date, location) into EPC Information Service

3. EPC信息服务向EPC发现服务注册EPC“知识”EPC Information Service registers EPC “knowledge” with EPC Discovery Service

4. 制造商向零售商发送产品Manufacturer sends product to Retailer

5. 零售商将产品的“接收”记录到EPC-IS中Retailer records “receipt” of product into EPC-IS

6. 零售商的EPC-IS然后向EPC Discovery Service注册产品“知识”Retailer’s EPC-IS then registers product “knowledge” with EPC Discovery Service

7. 如果零售商需要产品信息，则向Root ONS查询制造商本地ONS的位置If Retailer requires product information, Root ONS is queried for location of Manufacturer’s Local ONS

8.查询制造商的本地ONS以获取EPC-is的位置 Manufacturer’s Local ONS is queried for location of EPC-IS

9. 零售商向制造商EPC-IS查询所需的产品信息（例如，生产日期、到期日期等）Retailer queries Manufacturer EPC-IS for desired product information (e.g., manufacture date, expiration date, etc.)

（12）应用

①Inventory Tracking库存跟踪：为杂货店中的所有物品添加RFID标签。当购物车离开商店时，它会通过一个RFID收发器。购物车几秒钟内就会响起来。跟踪产品的整个生命周期。Add an RFID tag to all items in the grocery. As the cart leaves the store, it passes through an RFID transceiver. The cart is rung up in seconds. Track products through their entire lifetime.

②Keyless entry无钥匙进入

③Payment tokens支付代币：无接触信用卡，自动通行费支付 Contact-less credit cards，Automatic toll-payment

④Passports护照

⑤Tracking Books in Libraries图书馆图书跟踪：自助结账、自动归还图书、大型系统图书的自动分类Self-checkout、Automated book return、Automated sorting of books for large systems

⑥Manufacturing and Processing制造和加工：库存和生产过程监控仓库订单履行Inventory and production process monitoring Warehouse order fulfillment

⑦Supply Chain Management供应链管理：库存跟踪系统、物流管理Inventory tracking systems、Logistics management

⑧Retail零售：库存控制和客户洞察，利用逆向物流自动结账Inventory control and customer insight、Auto checkout with reverse logistics

⑨Security安全：访问控制、伪造和盗窃控制/预防Access control、Counterfeiting and Theft control/prevention

⑩Location Tracking位置跟踪：交通活动控制和停车管理、野生动物/牲畜监测和跟踪Traffic movement control and parking management、Wildlife/Livestock monitoring and tracking

（13）RFID Standards

Tracking Animals

ISO 11784 – Specifies the structure of the ID code

ISO 11785 – Specifies how transponder is activated

ISO 14223/1 – Specifies RF code for advanced transponders

Credit Cards

ISO 15693 – Specifies modulation and coding schemes

Passports cards

ISO 14443 – Specifies modulation and coding schemes

General Frequency bands

ISO 18000 series

ISO 18000-2

工作频率>135 KHzOperates at >135 KHz

磁感应的Inductive

不受水的影响Unaffected by presence of water

短距离（几厘米）Short range (a few centimeters)

由于转发器中的线圈，成本相当高Fairly costly because of coil in transponder

ISO 18000-3

  Operates at 13.56 MHz

  磁感应的Inductive

  Lower cost ~ 35 cents

  薄柔性形状因子（智能标签）Thin flexible form factor ( smart label )

  可读写Read / write capable

  不受水的影响Unaffected by water (but has to be tuned to item)

  中等距离Mid range, 70 – 125 cms

  Two flavors: Mode 1 Standard ISO 15693 data rate (26 kb/s)、Mode 2 High speed interface (848 kb/s)

ISO 18000-4

  Operates at 2.45 GHz

  传播Propagating

  双模式Dual Mode

  Passive Backscatter被动后向散射：被动标签目前已过时Passive tag currently out of fashion

  Active High data rate活动高数据速率：活动版本中的远程（100 m+）Long range in active version (100 m+)

  受水影响（信号吸收…微波）Affected by water (signal absorbed…microwave)

  可读/写Read / write capable

  中等成本Moderate cost

  小型天线Small antenna

ISO 18000-6 A/B

  Operates between 860 – 960 MHz

  传播Propagating

  Long range 2-5 m

  低成本Low cost

  高数据速率High data rates

  “频率灵活”“Frequency agile”

  可读/写Read / write capable

  相对较大的天线Relatively large antenna

  大规模应用RFID的未来The future for mass application

ISO 18000-7

  Operates at 433 MHz

  Active

  Long range - many m

  高成本High cost

  高速High data rates

  可读写Read / write capable

  Manifest tags- DoD

（14）RFID advantages over bar-codes

读取无需视线单次扫描可读取多个项目每个标签可携带大量数据（读/写）No line of sight required for reading Multiple items can be read with a single scan Each tag can carry a lot of data (read/write)

识别的单个项目，而不仅仅是类别Individual items identified and not just the category

被动标签的寿命几乎是无限的Passive tags have a virtually unlimited lifetime

活动标签可以远距离读取Active tags can be read from great distances

可与条形码技术相结合Can be combined with barcode technology

5.sensor

（1）定义

传感器是一种转换器，它测量物理量，并将其转换为可由观察者或（今天主要是电子）仪器读取的信号。A sensor is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument.

别称：transducer, probe, gauge, detector, etc.

（2）分类

Active sensors generate electric current or voltage directly in response to environmental stimulation. Examples of active transducers are thermocouples and piezoelectric accelerometers. 主动传感器响应于环境刺激直接产生电流或电压。有源传感器的例子是热电偶和压电加速度计。

Passive sensors produce a change in some passive electrical quantity, such as capacitance, resistance, or inductance, as a result of stimulation. These usually require additional electrical energy for excitation.无源传感器由于刺激会产生一些无源电量的变化，如电容、电阻或电感。这些通常需要额外的电能来激励。

Contact sensor接触传感器：需要与刺激物物理接触的传感器。示例：应变计、大多数温度传感器a sensor that requires physical contact with the stimulus. Examples: strain gauges, most temperature sensors

Non-contact sensor非接触式传感器：无需物理接触。示例：大多数光学和磁性传感器、红外温度计等。requires no physical contact. Examples: most optical and magnetic sensors, infrared thermometers, etc.

Measurement output测量输出：

• 传感器与传感器周围环境之间的相互作用Interaction between a sensor and the environment surrounding the sensor

• 多个输入的复合响应Compound response of multiple inputs

（3）输入输出

Input: stimulus or measurand被测量对象 (temperature pressure, light intensity, etc.)

Ouput: 电子信号electrical signal (voltage, current frequency, phase, etc.)

（4）Transfer function转化功能：Relation between input and output

别称：Input output characteristic function、transfer characteristic function、Response

Linear or nonlinear

一维或多维的分类One dimensional or multi dimensional：Single input, single output；Multiple inputs, single output

（5）Range and Span

Range:刺激的最低值和最高值lowest and highest values of the stimulus

Span: 在可接受误差范围内可感测到的刺激的最高值和最低值之间的算术差the arithmetic difference between the highest and lowest values of the stimulus that can be sensed within acceptable errors

Input full scale (IFS) = span

Output full scale (OFS):传感器输出的上限和下限之间的差difference between the upper and lower ranges of the output of the sensor corresponding to the span of the sensor

（6）Errors: deviation from “ideal”

As a difference: e = V – V0 (V0是实际值，V是测量值（传感器或致动器输出的刺激）V0 is the actual value, V is that measured value (the stimulus in the case of sensors or output in actuators).

来源: materials used、ageing、operational errors、calibration errors、noise、many others

分类

①Static errors静态错误：不依赖于时间not time dependent

②Dynamic errors动态错误：取决于时间time dependent

③System errors系统误差：测量装置和近似值的设计不完善。误差在任何时间和条件下都是恒定的。可通过校准进行校正imperfect design of the measurement setup and the approximation. errors are constant at all times and conditions. Can be corrected by calibration

④Random errors随机误差：不受控变量引起的变化。参数或不同操作时间的不同错误。可通过平均值减少variations due to uncontrolled variables. Different errors in a parameter or at different operating times. Can be reduced by averaging

（7）Resolution分度值

它可以对刺激做出反应的最小增量。输入变化的幅度导致最小的可识别输出。 the minimum increment in stimulus to which it can respond. It is the magnitude of the input change which results in the smallest discernible output.

Example:使用分辨率为0.1V的数字电压表测量传感器的输出。将在电压表上提供0.1V变化的输入（温度、压力等）变化是传感器/电压表系统的分辨率。a digital voltmeter with resolution of 0.1V is used to measure the output of a sensor. The change in input (temperature, pressure, etc.) that will provide a change of 0.1V on the voltmeter is the resolution of the sensor/voltmeter system.

（8）Accuracy vs. Resolution

传感器的分辨率是它能够检测到的测量量的最小变化。The resolution of a sensor is the smallest change it can detect in the quantity that it is measuring.

准确度告诉您传感器或测量仪器的输出或显示读数与“真实”值的匹配程度。Accuracy tells you how closely the output or displayed reading from a sensor or measuring instrument will match the ‘true’ value.

（9）Accuracy vs. Precision

Accuracy准确度：准确度是指测量值与实际（真实）值的接近程度。Accuracy is how close a measured value is to the actual (true) value.

Precision精度：精度是指测量值之间的接近程度。Precision is how close the measured values are to each other.

如果您多次测量某个值，并且所有值都接近，那么如果存在“偏差”，它们可能都是错误的If you measure something several times and all values are close, they may all be wrong if there is a "Bias"

Bias偏差是一种系统性（内置）误差，它使所有测量值都有一定的误差 is a systematic (built-in) error which makes all measurements wrong by a certain amount

（10）Repeatability/reproducibility重复性/再现性

当在不同时间测量时，传感器在相同条件下不能代表相同值（即刺激或输入）。failure of the sensor to represent the same value (i.e. stimulus or input) under identical conditions when measured at different times.

• 通常与校准相关usually associated with calibration

• 视为错误。viewed as an error.

• 两个读数之间的最大差值在相同的输入条件下在不同的时间拍摄。given as the maximum difference between two readings taken at different times under identical input conditions.

• 以输入满量程百分比表示的误差。error given as percentage of input full scale.

（11）Sensitivity

of a sensor is defined as the change in output for a given change in input, usually a unit change in input. Sensitivity represents the slope of the transfer function. 传感器的灵敏度定义为给定输入变化的输出变化，通常为输入单位变化。灵敏度表示传递函数的斜率。

（12）Hysteresis滞后

从两个不同方向接近时，传感器输出在任何给定点的偏差the deviation of the sensor’s output at any given point when approached from two different directions

由电气或机械系统引起磁化热特性Caused by electrical or mechanical systems Magnetization Thermal properties

（13）Linearity

传感器给定范围内输出与最佳拟合直线的偏差the deviation of the output from a best-fit straight line for a given range of the sensor

Nonlinear

传感器的特性（非线性传递函数）A property of the sensor (nonlinear transfer function) or:

由错误引入Introduced by errors

非线性误差影响精度。Nonlinearity errors influence accuracy.

非线性定义为与理想线性传递函数的最大偏差。Nonlinearity is defined as the maximum deviation from the ideal linear transfer function.

必须从实际传递函数或校准曲线推断出非线性Nonlinearity must be deduced from the actual transfer function or from the calibration curve

（14）Response time (or delay time),响应时间（或延迟时间）

表示输入阶跃变化时输出达到稳态（或给定百分比的稳态）所需的时间。 indicates the time needed for the output to reach steady state (or a given percentage of steady state) for a step change in input.

典型地，响应时间将作为在暴露于输入的单位阶跃变化时达到稳态输出的90%所需的时间。Typically the response time will be given as the time needed to reach 90% of steady state output upon exposure to a unit step change in input.

设备的响应时间是由于设备的惯性（“机械”和“电气”）。The response time of the device is due to the inertia of the device (both “mechanical” and “electrical”).

（15）Calibration校准

传感器传递函数的实验测定。通常，当传递函数未知时需要，或者当设备必须在低于制造商规定的公差下运行时需要。例如，在0至100°C的满量程上使用具有5%公差的热敏电阻来测量温度。the experimental determination of the transfer function of a sensor. Typically, needed when the transfer function is not known or, When the device must be operated at tolerances below those specified by the manufacturer. Example, use a thermistor with a 5% tolerance on a full scale from 0 to 100°C to measure temperature.

（16）Reliability可靠性

设备质量的一种统计度量，表明设备在正常运行条件下，在规定的时间段或循环次数内无故障地执行其规定功能的能力。a statistical measure of quality of a device which indicates the ability of the device to perform its stated function, under normal operating conditions without failure for a stated period of time or number of cycles.

以小时、年或MTBF（平均无故障时间）表示Given in hours, years or in MTBF (Mean Time Between Failure)

通常由制造商提供Usually provided by the manufacturer

基于加速寿命测试Based on accelerated lifetime testing

（17）实例

Light sensors光传感器用于照相机、红外探测器和环境照明应用。传感器由光电导体组成，如光致抗蚀剂、光电二极管或光电晶体管are used in cameras, infrared detectors, and ambient lighting applications.Sensor is composed of photoconductor such as a photoresistor, photodiode, or phototransistor

Humidity Sensor湿度传感器：测量-相对湿度（RH）是指空气中的水蒸气量，与使空气在当前温度下饱和所需的蒸气量相比Measurement - Relative humidity (RH) is the amount of water vapor in the air compared with the amount of vapor needed to make the air saturated at the air's current temperature

Temperature sensors 温度传感器出现在建筑、化工厂、发动机、电器、计算机和许多其他需要温度监控的设备中。许多物理现象取决于温度，因此我们通常可以通过测量压力、体积、电阻和应变来间接测量温度appear in building, chemical process plants, engines, appliances, computers, and many other devices that require temperature monitoring Many physical phenomena depend on temperature, so we can often measure temperature indirectly by measuring pressure, volume, electrical resistance, and strain

CO2 sensor CO2传感器测量环境中的气态CO2水平。监控红外线的多少辐射被CO2分子吸收 measures gaseous CO2 levels in an environment.Monitors how much infrared radiation is absorbed by CO2 molecules

Image Sensor 是一种将光信号转换为数字信号（颜色/RGB数据）的光敏器件。通常，常用的两种主要类型是CCD和CMOS传感器，主要用于数码相机和其他成像设备。CCD代表电荷耦合器件，CMOS代表互补金属氧化物半导体is a photosensitive device that converts light signals into digital signals (colours/RGB data). Typically, the two main types in common use are CCD and CMOS sensors and are mainly used in digital cameras and other imaging devices. CCD stands for Charged-Coupled Device and CMOS stands for Complementary Metal–Oxide–Semiconductor

Accelerometers 加速计用于沿一个轴测量，对正交方向不敏感 are used to measure along one axis and is insensitive to orthogonal directions

Magnetic Field sensors 磁场传感器用于动力转向、安全和输电线路上的电流测量。are used for power steering, security, and current measurements on transmission lines.

Ultrasonic sensors 超声波传感器用于位置测量are used for position measurements

6.Positioning and GPS

（1）Positioning technologies定位技术

定位技术正在彻底改变位置敏感应用的范围positioning technologies are revolutionising the scope of location- sensitive applications

Positioning technologies all use:

电磁频谱中的信号Signals in the electromagnetic spectrum

从已知点转换为距离的信号时差Signal time transit from known points converted to distance

为未知位置求解已知点的距离/方向Distances/ directions to known points are solved for the unknown position

2）Global Navigation Satellite Systems

依靠环绕地球轨道硬件的卫星系统（空间段）Satellite systems which depend upon hardware in orbit around the earth (space segment)

其他组件包括：地面站系统（控制部分）、手持接收器（用户部分）Other components include: a system of ground stations (control segment)、handheld receivers (user segment)

（3）GPS定义

国防部开发的无线电导航系统Radio-based navigation system developed by DoD

系统称为NAVSTARSystem is called NAVSTAR

卫星定时和测距导航NAVigation with Satellite Timing And Ranging

称为GPS Referred to as GPS

由24颗卫星组成的系列，6个轨道平面，每个平面上有4个卫星飞行器（SV）Series of 24 satellites, 6 orbital planes, 4 satellite vehicles (SV) on each plane

在世界任何地方工作，全天24小时，在所有天气条件下工作并提供：位置或位置固定、速度、行驶方向、准确的时间Works anywhere in the world, 24 hours a day, in all weather conditions and provides: Location or positional fix、Velocity、Direction of travel、Accurate time

全球定位系统（GPS）是一种天基卫星导航系统，它在地球上或附近的任何地方提供全天候的位置和时间信息，在那里，四颗或更多GPS卫星的视线是畅通的。它由美国政府维护，任何人都可以免费使用GPS接收器。The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather, anywhere on or near the Earth, where there is a unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver.

（4）Global Navigation Satellite Systems (GNSS)

USA：NAVSTAR

Russians：GLONASS

Europeans：Galileo

China：Beidou

（5）基本步骤

Positioning定位：知道SV在太空中的位置Knowing where SV is in space

Timing计时：需要精确的时钟Accurate clocks are required

SV RangingSV测距：确定与SV的距离Determining distance from SV (satellite vehicles )

Trilateration三边测量：球体的交点Intersection of spheres

Correction of errors误差校正：电离层和对流层延迟的校正Correcting for ionospheric and tropospheric delays

（6）GPS工作原理

每个卫星的计算距离=时间延迟*光速Range from each satellite calculated range = time delay * speed of light

称为三边测量的技术用于确定您的位置或“定位”Technique called trilateration is used to determine your position or “fix” 。球体的相交Intersection of spheres

2D定位至少需要3颗卫星At least 3 satellites required for 2D fix

但是，应始终使用4颗卫星，用于补偿GPS接收机时钟不准确的第四颗卫星，产生更好的精度并提供3D修复However, 4 satellites should always be used.The 4 th satellite used to compensate for inaccurate clock in GPS receivers.Yields much better accuracy and provides 3D fix

（7）Determining Range确定范围

接收机和卫星使用相同的代码，同步代码生成，将传入代码与接收器生成的代码进行比较Receiver and satellite use same code，Synchronized code generation，Compare incoming code with receiver generated code

（8）Signal Structure信号结构

每个卫星都发送自己的唯一代码Each satellite transmits its own unique code

两个频率：L1 Carrier 1575.42 MHz、L2 Carrier 1227.60 MHz

Codes：CA Code use L1 (civilian code)、P (Y) Code use L1 & L2 (military code)

（9）准确的时间是关键Accurate Timing is the Key

SV具有高度精确的原子钟SVs have highly accurate atomic clocks

接收机的时钟精度较低Receivers have less accurate clocks

使用“纳秒”进行测量：1纳秒=十亿分之一秒Measurements made using “nanoseconds” ：1 nanosecond = 1 billionth of a second

1/100秒的误差可能导致1860英里的误差1/100 th of a second error could introduce error of 1,860 miles

必须解决卫星和接收器时钟之间的差异Discrepancy between satellite and receiver clocks must be resolved

需要第四颗卫星来解决4个未知数（X、Y、Z和接收器时钟误差）Fourth satellite is required to solve the 4 unknowns (X, Y, Z and receiver clock error)

（10）Satellite Positioning卫星定位

方程中还需要求解4个未知数，即卫星的实际位置。Also required in the equation to solve the 4 unknowns is the actual location of the satellite.

SV处于相对稳定的轨道上，并在地面上持续监测SV are in relatively stable orbits and constantly monitored on the ground

SV位置向下广播到接收器SV position is broadcast down to receiver

（11）Sources of Errors误差来源

最大的来源是大气大气折射：带电粒子、水蒸气Largest source is due to the atmosphere Atmospheric refraction：Charged particles、Water vapor

卫星时钟错误Satellite clock errors

SV位置错误SV position errors

GPS接收机质量Quality of GPS receiver

多路径错误Multi-path errors

（12）误差：Multi-path

occurs when signals are reflected off of objects such as trees or buildings. These reflections delay the signal before it reaches the antenna and throw off the range calculations. Since accurate timing is necessary for accurate positioning, this can cause significant error. Multi-path is the greatest source of error in forestry settings and the most difficult to combat.当信号被树木或建筑物等物体反射时，会出现多路径。这些反射延迟了信号到达天线之前的时间，从而影响了距离计算。由于准确的定时对于准确的定位是必要的，这可能会导致严重的误差。多路径是林业环境中最大的错误来源，也是最难对付的。

（13）其他定位技术

①WiFi positioningWiFi定位：设备中的WiFi芯片检测接入点的名称、信号强度和（有时）到达角度WiFi chips in devices detect the name of the access point, signal strength, and (sometimes) angle of arrival

②Bluetooth positioning蓝牙定位：用于发送有关位置/服务的本地消息Used to send local messages about location/ services

③RFID chips embedded in the environment.RFID scanners can check location/ services available嵌入环境中的RFID芯片RFID扫描仪可以检查可用的位置/服务

（14）iBeacon: location-based services

iBeacon是苹果实施的蓝牙低能耗（BLE）无线技术，为iPhone和其他iOS设备提供基于位置的信息和服务创造了一种不同的方式。iBeacon可能是一个更好的室内地图选择，而GPS却很难做到这一点。iBeacon is Apple's implementation of Bluetooth low- energy (BLE) wireless technology to create a different way of providing location-based information and services to iPhones and other iOS devices. iBeacon could be a much better option for in-door mapping - which GPS struggles with.

信标本身是小型、廉价的蓝牙发射机。安装在iPhone上的应用程序会监听这些信标发送的信号，并在手机进入射程时做出相应响应。The beacons themselvers are small, cheap Bluetoothtransmitters. Apps installed on your iPhone listen out forthe signal transmitted by these beacons and respond accordingly when the phone comes into range.

例如，如果你在商店里通过一个信标，零售商的应用程序（假设你已经安装了它）可能会为你显示一个特别优惠警报。在参观博物馆时，博物馆的应用程序将提供有关最近展品的信息，使用您与展品附近放置的信标的距离来确定您的位置For example, if you pass a beacon in a shop, the retailer's app (assuming you have it installed) could display a special offer alert for you.On a visit to a museum, the museum's app would provide information about the closest display, using your distance from beacons placed near exhibits to work out your position

7.Smart Device

（1）Traditional computer

个人计算机（PC）是指任何通用计算机，其大小、功能和原始销售价格使其对个人有用，并由最终用户直接操作，无需计算机操作员干预。A personal computer (PC) is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator.

笔记本电脑（有时也称为笔记本电脑、笔记本电脑或上网本）是一种用于移动的个人电脑。A laptop computer (also sometimes called notebook computers, notebooks or netbooks) is a personal computer for mobile use.

（2）Tablet computer

平板电脑或平板电脑是一种移动计算机，比手机或个人数字助理更大，集成在平板触摸屏中，主要通过触摸屏幕而不是使用物理键盘来操作。 A tablet computer, or a tablet, is a mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen rather than using a physical keyboard.

Operating systems：Windows、Linux、iOS、Android、Blackberry Tablet OS

（3）PDA

个人数字助理（PDA），也称为掌上电脑或个人数据助理，是一种用作个人信息管理器的移动设备。随着智能手机的广泛应用，PDA在很大程度上被认为是过时的。A personal digital assistant (PDA)/palmtop computer/personal data assistant, is a mobile device that functions as a personal information manager. PDAs are largely considered obsolete with the widespread adoption of smartphones.

The most common operating systems preinstalled on PDAs are: Palm OS、Microsoft Windows Mobile with a Windows CE kernel.、Android、iOS

（4）智能手机

是一款基于移动操作系统的手机，具有更先进的计算能力和连接能力。smartphone is a mobile phone built on a mobile operating system, with more advanced computing capability and connectivity.

Operating systems Symbian、BlackBerry、Android、iOS、Windows

（5）Home automation家庭自动化

是指家庭、家务或家庭活动的自动化。它可能包括集中控制照明、HVAC（供暖、通风和空调）、电器和其他系统，以提高便利性、舒适性、能效和安全性。 is automation of the home, housework or household activity. It may include centralized control of lighting, HVAC (heating, ventilation and air conditioning), appliances, and other systems, to provide improved convenience, comfort, energy efficiency and security.

（6）Wearable computers/body-borne computers可穿戴计算机/体载计算机

是一种微型电子设备，由携带者穿戴在衣服下面、里面或上面 are miniature electronic devices that are worn by the bearer under, with or on top of clothing

8.Wireless Sensing

（1）接触式感知Contact Sensing

a.k.a. 可穿戴传感、基于设备的传感Wearable Sensing, Device-based Sensing

（2）非接触式感知Contact-free Sensing：Four types of sensing media: Light, Sound, Electricity, 磁Magnetism

①光Light: 计算机视觉Computer Vision, 红外传感Infrared/IR Sensing

②声Sound: Acoustic Sensing

2 types of sensing media：Audio (<20kHz)、Ultrasound (>20kHz, unaudible)

③Magnetism

④Electricity: 电磁波、射频（RF）传感、雷达（无线电探测和测距）Electromagnetic Wave, Radio Frequency (RF) Sensing，RADAR (Radio Detection and Ranging)

3 types of commonly used wireless media：WiFi（RSSI（接收信号强度指示符）CSI（信道状态信息））、毫米波、UWB（超宽带）WiFi（RSSI (Received Signal Strength Indicator) CSI (channel state information) ）、Millimeter Wave、UWB (Ultra Wide Band)

Basic Principle: 传输路径中的目标（如人类）将根据物理定律反射、折射、衍射和散射RF信号。通过捕获这些信号并处理模式，可以感测环境中的事件。Targets such as humans in the transmission paths will reflect, refract, diffract, and scatter the RF signals following physical laws. By capturing these signals and processing the patterns, events in the environment can be sensed.

Advantages of RF sensing

射频传感由于其非接触性，以及其他优点，如普及性、低成本（金钱和能源）和隐私保护，提高了可用性。RF sensing has improved usability due to its contactless nature, along with other benefits such as pervasiveness, low cost (in both money and energy), and privacy preservation.

它可用于评估各种目标的存在、状态和活动，因此已成为许多高级应用的支持技术。It can be used to estimate presence, status, and activity of various targets, and has thus become the enabling technology for many high-level applications.

（3）Wireless Sensing

Acoustic Sensing、RF Sensing、RFID (contact sensing)

9.Crowd Sensing

“众包是一种传统上由指定代理人（通常是员工）完成的工作，并以公开电话的形式将其外包给一个不确定的、通常很大的群体的行为。”（Jeff Howe，Wired 2006）“Crowdsourcing is the act of taking a job traditionally performed by a designated agent (usually an employee) and outsourcing it to an undefined, generally large group of people in the form of an open call.” (Jeff Howe, Wired 2006)

Web-based Crowdsourcing Web 2.0: Data created by users

Background of Mobile CrowdSensing：More Intensive Information Perception移动人群感知的背景：更密集的信息感知

Traditional sensing paradigm：Proactively Deploying Sensor Networks

New Sensing Paradigm: Mobile Crowd Sensing

定义：它将普通用户的移动设备视为基本感知单元，通过有意识或无意识地通过移动互联网相互协作，利用它们来分配感知任务和收集感知数据，以完成大规模和复杂的社会感知任务It treats mobile devices of ordinary users as basic sensing units, and leverage them to distribute sensing tasks and collecting sensing data by consciously or unconsciously collaborating with each other through the mobile Internet for completing large-scale and complex social sensing tasks

（3）Advantages of Mobile Crowd Sensing

Low cost:以较低的成本部署网络更容易，因为世界上许多城市已经存在数百万移动设备或车辆。此外，可以利用人的移动性来提高传感覆盖范围和数据传输。一方面，移动节点可以在其持有者偶然到达的任何地方感知周围环境，这使得能够构建大规模的感知应用。另一方面，移动用户之间的机会接触可以被利用来在具有基于商店结转模式的间歇性连接的网络中传递感官数据。 It is easier to deploy the network at lower cost, because millions of mobile devices or vehicles already exist in many cities around the world. Moreover, human mobility can be exploited to improve sensing coverage and data transmission. On one hand, mobile nodes can sense the surroundings wherever their holders arrive opportunistically, which enables building largescale sensing applications. On the other hand, opportunistic contacts among mobile users can be exploited to deliver sensory data in networks with intermittent connections based on the store-carry-and-forward paradigm.

Easy maintenance: 维护网络更容易，因为移动节点通常具有更多的电源、更强的计算机、更大的存储容量和通信容量。此外，移动节点始终由其持有者管理并保持在良好状态。例如，人们可以根据需要每天给手机充电。It is easier to maintain the network, because mobile nodes often have more power supply, stronge r comput a tion, and l a rge r stor age , and communication capacity. Moreover, mobile nodes are always managed and maintained in good condition by their holders. For example, people could charge their mobile phones as needed every day.

Good scalability: 它更具可扩展性和灵活性，因为我们只需要招募更多的用户来适应系统规模的扩大。It is more extensible and flexible, because we only need to recruit more users to adapt to the expansion of the system scale.

（4）挑战Challenges of Mobile Crowd Sensing

Sensing quality: 移动用户的数量、传感器的可用性和数据质量总是随着时间的推移而变化，这是由于人类移动的随机性和人类环境的动态性，例如移动节点的剩余电池能量和人们的偏好。所有这些因素使得在覆盖范围、延迟和置信度方面更难保证可靠的传感质量。The number of mobile users, the availability of sensors, and the data quality always change over time due to the randomness of human mobility and the dynamics of human contexts such as the residual battery energy of mobile nodes and people’s preferences. All these factors make it more difficult to guarantee reliable sensing quality in terms of coverage, latency, and confidence.

Privacy Protection: 人类的参与自然会带来隐私问题。移动用户可能不想分享他们的感官数据，这些数据可能包含或透露他们的隐私和敏感信息（例如，他们的当前位置）。Human involvement naturally brings privacy concerns. Mobile users may not want to share their sensory data, which may contain or reveal their private and sensitive information (e.g., their current location).

Incentive: 在参与MCS时，移动用户会消耗自己的资源（例如电池和计算能力），并存在潜在的隐私威胁。因此，激励机制对于为参与者提供足够的参与成本奖励是必要的。从传感的角度来看，必须为用户提供完成特定传感任务的适当激励。从传输的角度来看，用户需要为彼此转发数据而获得奖励。While participating in MCS, mobile users consume their own resources (e.g., battery and computing power) and have potential privacy threats. Thus, incentive mechanisms are necessary to provide participants with enough rewards for their participation costs. From the sensing perspective, proper incentives must be offered to users for completing specific sensing tasks. From the transmission perspective, users need to be rewarded for forwarding data for each other.