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Global Positioning Systems What is GPS? **A global positioning system (GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the receiver\'s geographic location** (Figure 8-5). A GPS receiver is a han...

Global Positioning Systems What is GPS? **A global positioning system (GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the receiver\'s geographic location** (Figure 8-5). A GPS receiver is a handheld, mountable, or embedded device - **A GPS receiver typically includes:** - **An antenna** to receive satellite signals - **A radio receiver** to process the signals - **A processor** to calculate the position - **A display screen** (optional) to show location information Some also function as a portable media player. Many mobile devices such as smart phones have GPS capability built into the device or as an add-on feature. Some users carry a handheld GPS receiver; others mount a receiver to an object such as an automobile, boat, airplane, farm and construction equipment, or computer. **GPS technology has a wide range of applications, including:** - **Navigation for vehicles, boats, airplanes** - **Mapping and surveying** - **Location-based services (e.g., finding nearby restaurants, ATMs)** - **Tracking people or objects** - **Precision agriculture** - **Emergency services** The first and most used application of GPS technology is to assist people with determining where they are located. The data obtained from a GPS, however, can be applied to a variety of other uses: creating a map, ascertaining the best route between two points, locating a lost person or stolen object, monitoring the movement of a person or object, determining altitude, and calculating speed. Many vehicles use GPSS to provide drivers with directions or other information. Read Innovative Computing 8-1 to find out about a hobby that uses GPS technology. **How It Works** **Step 1: Satellite Signals** **GPS satellites orbit Earth every thousandth of a second, each satellite sends a signal that indicates its current position to the GPS receiver.  ** Imagine there are 24 tiny spaceships called satel lites circling our Earth. These satellites are super fast! They zoom around the Earth so quickly that it feels like they\'re there and gone in the blink of an eye. Every time a satellite passes by, it sends out a special message telling everyone where it is at that exact moment. **Step 2: Receiver Calculation** **A GPS receiver (such as in a car, a wearable device, a smartphone, a handheld device, or a collar) determines its location on Earth by analyzing at least 3 separate satellite signals from the 24 satellites in orbit** To figure out where you are on Earth, your GPS receiver needs to hear from at least 3 different satellites. It\'s like having 3 friends tell you where they are, and then you figuring out where you must be based on their locations. The GPS receiver listens to the messages from these 3 satellites and does some clever math. Using the information about where the satellites are, it can calculate exactly where you are on Earth! Geocaching for Hidden Treasure What is Geocaching? **Geocaching is a real-world treasure hunting game using GPS-enabled devices. Participants hide containers called \"caches\" and share their GPS coordinates online. Other players then use their GPS devices to find these hidden caches.** Treasure hunting for all ages has gone high-tech. Geocaching is a form of outdoor recreation, discovery, and fun, and the only requirements are a GPS receiver, Internet access, and a sense of adventure. **How Geocaching Works** 1. **Hiding a Cache: Participants hide a cache in an interesting location and log the GPS coordinates on a geocaching website.** 2. **Finding a Cache: Other players use their GPS devices and the coordinates to find the hidden cache.** 3. **Logging Your Find: Once found, players sign the logbook inside the cache and share their experience online.** Participants bury or hide a small container, called a cache, that has a logbook and writing instrument and usually a small novelty trinket such as a coin, button, toy, or CD. They then log on to a geocaching Web site and post details of the container\'s location using latitudinal and longitudinal coordinates. Cachers then use their GPS receivers to find the container, note their discovery in the logbook, and write about their adventure on the Web site. The first cache with GPS coordinates was documented in 2000. Today, more than 900,000 geocaches in more than 100 countries and on all 7 continents are registered on a variety of Web sites, such as geocaching.com. The locations range from under water to mountain peaks. Cachers generally follow the Geocacher\'s Creed, which encourages ethical behavior and preservation of natural resources. Collaboration Many software products provide a means to collaborate, or work online, with other users connected to a server. **Two methods of collaboration include collaborative software and document management systems.** **Collaborative software enables users to share documents and communicate with others in real-time through online meetings. These meetings can be held on the web, known as web conferences. All participants can view and edit a document simultaneously, with changes reflected for everyone. Collaborative software often includes features like chat, whiteboards, and video/audio conferencing.** Collaborative software includes tools that enable users to share documents via online meet- ings and communicate with other connected users. An online meeting allows users to share documents with others in real time (Figure 8-6). When the online meeting takes place on the Web, it is called a Web conference. In an online meeting, all participants see a document(s) at the same time. As some- one changes the document, everyone in the meeting sees the changes being made. Collaborative soft- ware often has chat, whiteboard, and video/audio conferencing capabilities. Some organizations use document management systems to make collaboration possible among employees. **Document management systems store and manage a company\'s documents, such as word processing documents, presentations, and spreadsheets. Users can access these documents based on their needs. These systems track document changes, creation dates, creators, summaries, and associated keywords. Google Docs is a popular example of a web-based document management system.** A document management system provides for storage and management of a company\'s docu- ments, such as word processing documents, presentations, and spreadsheets. Users then access these documents, depending on their needs. A document man- agement system can track all changes made to a document. It also can store additional information such as the document\'s creation date, the user who created the document, a summary of the document, and any keywords associated with the document. Google Docs is a Web-based document management system that provides basic services to its subscribers at no cost. With Google Docs, multiple users can work on the same document at the same time, viewing each others edits as they are entered. Groupware **Groupware is software that facilitates collaboration and information sharing among groups of people over a network. It\'s a key component of workgroup computing, encompassing network hardware and software that enables group members to:** - **Communicate effectively** - **Manage projects efficiently** - **Schedule meetings seamlessly** - **Make informed group decisions** Groupware is software that helps groups of people work together on projects and share information over a network. Groupware is a component of a broad concept called workgroup computing, which includes network hardware and software that enables group members to communicate, manage projects, schedule meetings, and make group decisions. **Most groupware solutions incorporate Personal Information Manager (PIM) functions, such as:** - **Electronic appointment calendars** - **Address books** - **Notepads** **A standout feature of groupware is group scheduling, which involves a shared calendar to track multiple users\' schedules and coordinate appointments and meeting times.** To assist with these activities, most groupware provides personal information manager (PIM) functions, such as an electronic appointment calendar, an address book, and a notepad. A major feature of groupware is group scheduling, in which a group calendar can track the schedules of multiple users and help coordinate appointments and meeting times. Voice Mail **Voice mail functions like an answering machine, allowing users to leave voice messages. However, unlike answering machines, voice mail systems digitize and store messages on a hard disk.** Voice mail, which functions much like an answering machine, allows someone to leave a voice message for one or more people. Unlike answering machines, however, a computer in the voice mail system converts an analog voice message into digital form. Once digitized, the message is stored in a voice mailbox. A voice mailbox is a storage location on a hard disk in the voice mail system. **Visual voice mail allows users to view message details like length and, in some cases, read message contents instead of listening to them.** To help users manage voice mail messages, some systems offer visual voice mail. With visual voice mail, users can view message details such as the length of calls and, in some cases, read message contents instead of listening to them. Some voice mail systems can send digital voice mail files to e-mail addresses. Others can convert a voice mail message to a text message for display on a computer or mobile device. Web Services **Web services are standardized software that enables applications to communicate over the internet or internal networks. Businesses use web services to interact with departments, suppliers, vendors, and clients.** Web services describe standardized software that enables programmers to create applications that communicate with other remote computers over the Internet or over an internal business network. Businesses are the primary users of Web services because this technology provides a means for departments to communicate with each other, suppliers, vendors, and with clients. For example, third-party vendors can use Web services to communicate with their online retailer\'s Web site to manage their inventory levels. **Mashups combine services from multiple sources to create new applications. For example, an e-commerce business might combine its store location with a map from a travel and mapping website.** Web services often provide content for mashups. A mashup is a Web application that combines services from two or more sources, creating a new application. An e-commerce business, for example, might determine the address of its closest retail store from its Web site and combine (mash) the location with a map from a travel and mapping Web site to provide the Web site visitor with driving directions. **Communications software consists of programs that:** - **Help users establish a connection to another computer or network.** - **Manage the transmission of data, instructions, and information.  ** - **Provide an interface for users to communicate with one another.  ** Communication software refers to applications or programs designed to facilitate the exchange of information between different systems or users. It enables the transfer of data, instructions, and information in various formats, including text, audio, and video. Communications software consists of programs that (1) help users establish a connection to another computer or network; (2) manage the transmission of data, instructions, and information; and (3) provide an interface for users to communicate with one another. The first two are system software and the third is application software. **Chapter 3 presented a variety of examples of application software for communications:** - **e-mail** - **FTP** - **Web browser** - **newsgroup/message boards** - **chat rooms** - **instant messaging** - **video conferencing** - **VoIP** **Communications Devices and Software** - **Some communications devices are preprogrammed to accomplish communication tasks, while others require separate communications software.** - **Communications software works with network standards and protocols to ensure data moves correctly through a network.** - **Communications software is usually bundled with the operating system or purchased network devices.** - **Often, a computer has various types of communications software, each serving a different purpose.** - **One type helps users establish a connection to the Internet using wizards, dialog boxes, and other on-screen messages.** - **Communications software also allows home and small office users to configure wired and wireless networks and connect devices to an existing network.  ** Some communications devices are preprogrammed to accomplish communications tasks. Other communications devices require separate communications software to ensure proper transmission of data. Communications software works with the network standards and protocols defined earlier to ensure data moves correctly through a network. Communications software usually is bundled with the operating system or purchased network devices. Often, a computer has various types of communications software, each serving a different purpose. One type of communications software helps users establish a connection to the Internet using wizards, dialog boxes, and other on-screen messages. Communications software also allows home and small office users to configure wired and wireless networks and connect devices to an existing network. **Communications over the Telephone Network** **The Public Switched Telephone Network (PSTN)** **The PSTN is the global telephone system that handles voice-oriented calls. It primarily uses digital technology, except for the final link to homes, which is often analog.** **The telephone network is an integral part of computer communications. Data, instructions, and information are transmitted over the telephone network using dial-up lines or dedicated lines** The public switched telephone network (PSTN) is the worldwide telephone system that handles voice-oriented telephone calls (Figure 8-15). Nearly the entire telephone network today uses digital technology, with the exception of the final link from the local telephone company to a home, which often is analog. The telephone network is an integral part of computer communications. Data, instructions, and information are transmitted over the telephone network using dial-up lines or dedicated lines. The following sections discuss various types of lines that use the telephone network for data communications. **Dial-Up Lines** **A dial-up line is a temporary connection that uses one or more analog telephone lines for communications. A dial-up connection is not permanent. Using a dial-up line to connect computers costs no more than making a regular telephone call.** **Dedicated Lines** **A dedicated line is a type of always-on connection that is established between two communications devices (unlike a dial-up line where the connection is reestablished each time it is used). The quality and consistency of the connection on a dedicated line are better than a dial-up line because dedicated lines provide a constant connection**. Businesses often use dedicated lines to connect geographically distant offices. Dedicated lines can be either analog or digital. Digital lines increasingly are connecting home and business users to networks around the globe because they transmit data and information at faster rates than analog lines. **Types of Digital Dedicated Lines** - **ISDN lines** - **DSL** - **FTTP** - **T-carrier lines** - **ATM** Five types of digital dedicated lines are ISDN lines, DSL, FTTP, T-carrier lines, and ATM. Although cable television (CATV) lines and fixed wireless are not a type of telephone line, they are very popular ways for the home user to connect to the Internet. Fixed wireless Internet connections use an antenna on your house or business to communicate with a tower location via radio signals. Later sections in this chapter discuss the use of CATV lines and radio signals to connect to the Internet. The table in Figure 8-16 lists the approximate monthly costs of various types of Internet con- nections and transfer rates (speeds), as compared with dial-up lines. The following sections discuss ISDN lines, DSL, FTTP, T-carrier lines, and ATM. ISDN Lines For the small business and home user, an ISDN line provides faster transfer rates than dial-up telephone lines. Not as widely used today as in the past, **ISDN (Integrated Services Digital Network) is a set of standards for digital transmission of data over standard copper telephone lines.** DSL is a popular digital line alternative for the small business or home user. **DSL (Digital Subscriber Line) transmits at fast speeds on existing standard copper telephone wiring.** Some DSL installations include a dial tone, providing users with both voice and data communications. ADSL is one of the more popular types of DSLs. **ADSL (asymmetric digital subscriber line) is a type of DSL. that supports faster transfer rates when receiving data (the downstream rate) than when sending data (the upstream rate).** ADSL is ideal for Internet access because most users download more information from the Internet than they upload. **FTTP, which stands for Fiber to the Premises, uses fiber-optic cable to provide extremely high-speed Internet access to a user\'s physical permanent location.** Two specific types of FTTP are FTTH (Fiber to the Home) and FTTB (Fiber to the Building). With FTTP service, an optical terminal at your premises receives the signals and transfers them to a router connected to your computer. As the cost of installing fiber decreases, increasingly more homes and businesses will opt for this high-speed Internet access. **T-Carrier Lines AT-carrier line is any of several types of long-distance digital telephone lines that carry multiple signals over a single communications line.** T-carrier lines provide very fast data transfer rates. Only medium to large companies usually can afford the investment in T-carrier lines because these lines are so expensive. The most popular T-carrier line is the T1 line. Businesses often use T1 lines to connect to the Internet. Many Internet access providers use T1 lines to connect to the Internet backbone. Home and small business users purchase fractional T1, in which they share a connection to the T1 line with other users. Fractional T1 is slower than a dedicated T1 line, but it also is less expensive. AT3 line is equal in speed to 28 T1 lines. T3 lines are quite expensive. Main users of T3 lines include large corporations, telephone companies, and Internet access providers connecting to the Internet backbone. The Internet backbone itself also uses T3 lines. **ATM (Asynchronous Transfer Mode) is a service that carries voice, data, video, and multimedia at extremely high speeds.** Telephone networks, the Internet, and other networks with large amounts of traffic use ATM. Some experts predict that ATM eventually will become the Internet standard for data transmission, replacing T3 lines.