Tracking System Active versus passive tracking Global Positioning System (GPS) GPRS Mapping Common uses Major markets Technologies Used in Vehicle Tracking Tracking System A vehicle tracking system is an electronic device installed in a vehicle to enable the owner or a third party to track the vehicle's location. Most modern vehicle tracking systems use Global Positioning Systems (GPS) modules for accurate location of the vehicle. Many systems also combine a communications component such as cellular or satellite transmitters to communicate the vehicle’s location to a remote user. Vehicle information can be viewed on electronic maps via the Internet or specialized software. Current vehicle tracking systems have their roots in the shipping industry. Corporations with large fleets of vehicles required some sort of system to determine where each vehicle was at any given time. Vehicle tracking systems can now also be found in consumers vehicles as a theft prevention and retrieval device. Police can an follow the signal emitted by the tracking system to locate a stolen vehicle. Many vehicle tracking systems are now using or a form of Automatic Vehicle Location (AVL) to allow for easy location of the vehicle. The GPS satellite system was built and is maintained by government and is available at no cost to civilians. This makes this technology very inexpensive. Other AVL systems do not require the antenna to be in direct line of sight with the sky. Terrestrial based systems such as LORAN and LoJack tracking units use Radio frequency (RF) transmitters which will transmit through walls, garages, or buildings. Many police cruisers around the world have a form of AVL tracking as standard equipment in their vehicles. Some vehicle tracking systems charge the user a monthly subscription for a bundle that includes mapping software, hardware, installation, and tracking service. Other companies offer units that are paid for upon installation and will continue to work for the life of the vehicle. The decision to adopt an active technology based on RF (e.g. LORAN), satellite or public carrier (e.g., GSM or CDMA) is driven by the quantity of information, the frequency of updates, and the physical environment of the device. For example a fleet manager may want 5 minute updates, telling whether a vehicle is on or off, or may want 30 second updates tracking engine vitals, brake status, container status, vehicle speed and direction and so on. Active versus passive tracking Top Several types of Vehicle Tracking devices exist. Typically they are classified as Passive and Active. Passive devices store GPS location, speed, heading and sometimes a trigger event such as key on/off, door open/closed. Once the vehicle returns to a predetermined point, the device is removed and the data downloaded to a computer for evaluation. Passive systems include auto download type that transfer data via wireless download. Active devices also collect the same information but usually transmit the data in real-time via cellular or satellite networks to a computer or data center for evaluation. Some taxi services are using vehicle tracking systems for better serving their customers. By using Vehicle Tracking Systems, their operators can see all their empty taxis, so they can choose the closer one to pick up the order from their customer. GPS (Global Positioning System) Top The Global Positioning System (GPS) is the only fully functional Global Navigation System (GNSS). The GPS uses a constellation of between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals, that enable GPS receivers to determine their location, speed, direction, and time. GPS was developed by the United States Department of Defense. Its official name is NAVSTAR-GPS. Although NAVSTAR-GPS is not an acronym, a few backronyms have been created for it. The GPS satellite constellation is managed by the United States Air Force 50th Space Wing. Similar satellite navigation systems include the Russian GLONASS (incomplete as of 2008), the upcoming European Galileo positioning system, the proposed COMPASS navigation system of China, and IRNSS of India. Following the shooting down of Korean Air Lines Flight 007 in 1983, President Ronald Regan issued a directive making the system available free for civilian use as a common good. Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, and hobbies such as geocaching. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks. The early days of GPS Like the Internet, which arose from a 1969 research project of the U.S. Defense Department, GPS began as a military research project in the 1960s and 1970s. The idea was to fly atomic clocks on satellites and use the data for navigation. The system has several components: a constellation of 24 NAVSTAR satellites (operated by the U.S. Air Force) in Earth orbit with atomic clocks aboard, ground stations that control the system, five on-orbit spare satellites and receivers for users. GPS satellite launches started in 1978, and second-generation satellites were launched beginning in 1989. The system became fully operational in 1995, with a signal for military users and a less-accurate signal for civilians, but the commercial market had begun to open up more than a decade earlier. In 1983, Soviet jet interceptors shot down a Korean Air civilian airliner carrying 269 passengers that had mistakenly entered Soviet airspace. Because crew access to better navigational tools might have prevented the disaster, President Ronald Reagan issued a directive guaranteeing that GPS signals would be available at no charge to the world when the system became operational. The commercial market has grown steadily ever since. In 2004, President Bush issued an updated policy that keeps civilian GPS free of direct user fees. How GPS works GPS satellites transmit signals to equipment on the ground. GPS receivers need a clear view of the sky, so current technology is used mainly outside and does not work well in mountainous areas or near forests or tall buildings. Each GPS satellite transmits data that indicate its location and the current time. All GPS satellites synchronize operations so these repeating signals are transmitted at the same instant. Ground stations precisely track each satellite's orbit. GPS satellites transmit signals on two main carrier frequencies -- L1 and L2. The signals, moving at the speed of light, arrive at a GPS receiver at slightly different times because some satellites are farther away than others. The distance to the GPS satellites can be determined by estimating the amount of time it takes for their signals to reach the receiver. When the receiver estimates the distance to at least four GPS satellites, it calculates its position in three dimensions. The accuracy of a GPS-determined position depends on the receiver. Most hand-held GPS units have 10-meter to 20-meter accuracy. Other receivers use a method called differential GPS (DGPS) for much higher accuracy. DGPS requires one roving receiver and one receiver fixed at a known location nearby. Observations made by the fixed receiver are used to correct positions that the roving units record and are accurate to less than 1 meter. When the GPS system was created, the Defense Department inserted timing errors into its transmissions to limit the accuracy of nonmilitary GPS receivers to 100 meters. This “selective availability” was eliminated in May 2000. International Development Today, research is under way in the United States, Australia, France, the United Kingdom and Japan into “ubiquitous” positioning. The system would work everywhere, would be available all the time with a high level of precision and an acceptable cost, but it is still a long way from reality. In the meantime, other countries -- including Russia, the European Union, Japan and China -- are developing their own international satellite navigation systems. The Russian system, GLONASS (for Global Navigation Satellite System), is a radio satellite navigation system whose satellites began entering service in 1983. The system, operated for the Russian government by the Russian Space Forces, was complete in 1995. Like GPS, the GLONASS constellation consists of 24 satellites -- 21 operating and three on-orbit spares. Because of troubled economic conditions in Russia, only about 14 satellites are now operating, according to media reports. The Russians developed an advanced GLONASS satellite with an operational life of seven years and launched a three-satellite block of the new version on December 26, 2004. An even more improved GLONASS satellite, with reduced weight and an operational life of 10 to 12 years, is due to enter service in 2008. In a 2005 joint venture with Russia, the Indian government agreed to share development costs of the improved GLONASS satellites and launch two of them from India. With this help, the Russians propose to have GLONASS operational again by 2008 with 18 satellites, and by 2010 with 24 satellites. The European Union (EU) is building an alternative to GPS and GLONASS. The proposed Galileo positioning system will be a 30-satellite satellite navigation system that should be operational by 2010. Galileo is intended to give users access to greater precision than is now available, according to the EU, and improve coverage of satellite signals at higher latitudes. Only one of Galileo’s planned four navigation services will be available at no charge to users. Since 2003, several countries have joined the project – China (which is investing $296 million), Israel, Ukraine, India, Morocco, Saudi Arabia and South Korea. Japan also plans to build a regional three-satellite positioning system called the Quasi-Zenith Satellite System (QZSS) that will supplement and be interoperable with GPS. The first satellite launch is scheduled for 2008, the second and third in 2009. QZSS could improve regional service for positioning, timing and navigation users in Japan and surrounding areas, where mountainous terrain and population density sometimes make GPS unavailable. China is also developing an independent navigation satellite system. The Twinstar Rapid Positioning System, or Beidou Navigation System, consists of two satellites in geosynchronous orbits. Two satellites were launched in 2000, and China plans to complete the system with a second pair, media reports say. Another satellite was put into orbit in 2003. China is also associated with the EU Galileo system. Future GPS Over the last decade, the United States has implemented several improvements to GPS service, including new signals for civil use and increased accuracy and integrity for all users. Among these improvements are new satellite signals for civilian use – L2C, L5 and L1C. L2C, available now, will improve as newer satellites are added to the GPS constellation. It will also be interoperable with Japan’s QZSS. L5 will be available after the next improved GPS satellite launches later this year. L5 will transmit at a higher power than current civil GPS signals and have a wider bandwidth. It will be compatible with Galileo, GLONASS and QZSS. Its lower frequency may improve indoor reception. L1C arose from an agreement on GPS and Galileo signed by the United States and EU member states to have a compatible and interoperable signal on the L1 frequency. L1C will have an advanced design and be broadcast at a higher power level. “Global GPS sales have surpassed $20 billion a year,” said the Commerce Department’s David Sampson, “and will keep on growing at a healthy rate, according to industry estimates.” More than 95 percent of GPS units sold, he added, are sold for civilian use. “All of this extraordinary development and growth,” Sampson said, “is the result of consistent government policies that encourage civilian and commercial use of GPS.” Sources of GPS Signal errors Factors that can degrade the GPS signal and thus affect accuracy include the following: Ionosphere and troposphere delays — The satellite signal slows as it passes through the atmosphere. The GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error. Signal multipath — This occurs when the GPS signal is reflected off objects such as tall buildings or large rock surfaces before it reaches the receiver. This increases the travel time of the signal, thereby causing errors. Receiver clock errors — A receiver's built-in clock is not as accurate as the atomic clocks onboard the GPS satellites. Therefore, it may have very slight timing errors. Orbital errors — Also known as ephemeris errors, these are inaccuracies of the satellite's reported location. Number of satellites visible — The more satellites a GPS receiver can "see," the better the accuracy. Buildings, terrain, electronic interference, or sometimes even dense foliage can block signal reception, causing position errors or possibly no position reading at all. GPS units typically will not work indoors, underwater or underground. Satellite geometry/shading — This refers to the relative position of the satellites at any given time. Ideal satellite geometry exists when the satellites are located at wide angles relative to each other. Poor geometry results when the satellites are located in a line or in a tight grouping. Intentional degradation of the satellite signal — Selective Availability (SA) is an intentional degradation of the signal once imposed by the U.S. Department of Defense. SA was intended to prevent military adversaries from using the highly accurate GPS signals. The government turned off SA in May 2000, which significantly improved the accuracy of civilian GPS receivers. GPRS Top General Packet Radio Service (GPRS) is a packet oriented Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones. It provides data rates from 56 up to 114 kbit/s. GPRS can be used for services such as Wireless Application Protocol (WAP) access, Short Message Service (SMS), Multimedia Messaging Service (MMS), and for Internet communication services such as email and World Wide Web access. GPRS data transfer is typically charged per megabyte of traffic transferred, while data communication via traditional circuit switching is billed per minute of connection time, independent of whether the user actually is using the capacity or is in an idle state. GPRS is a best effort packet switched service, as opposed to circuit switching, where a certain Quality of Service (QoS) is guaranteed during the connection for non-mobile users. 2G cellular systems combined with GPRS are often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused Time division multiple access (TDMA) channels in, for example, the GSM system. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that GSM is the only kind of network where GPRS is in use. GPRS is integrated into GSM Release 97 and newer releases. It was originally standardized by European Telecommunications Standards Institute (ETSI), but now by the 3rd Generation Partnership Project (3GPP). GPRS Basics The multiple access methods used in GSM with GPRS are based on frequency division duplex (FDD) and TDMA. During a session, a user is assigned to one pair of up-link and down-link frequency channels. This is combined with time domain statistical multiplexing, i.e. packet mode communication, which makes it possible for several users to share the same frequency channel. The packets have constant length, corresponding to a GSM time slot. The down-link uses first come first served packet scheduling, while the up-link uses a scheme very similar to reservation ALOHA. This means that slotted Aloha (S-ALOHA) is used for reservation inquiries during a contention phase, and then the actual data is transferred using dynamic TDMA with first-come first-served scheduling. GPRS originally supported (in theory) Internet Protocol (IP), Point-to-Point Protocol (PPP) and X.25 connections. The last has been typically used for applications like wireless payment terminals, although it has been removed from the standard. X.25 can still be supported over PPP, or even over IP, but doing this requires either a router to perform encapsulation or intelligence built in to the end-device/terminal e.g. UE(User Equipment). In practice, the mobile built-in browser uses IPv4. In this mode PPP is often not supported by the mobile phone operator, while IPv6 is not yet popular. But if the mobile is used as a modem to the connected computer, PPP is used to tunnel IP to the phone. This allows DHCP to assign an IP Address and then the use of IPv4 since IP addresses used by mobile equipment tend to be dynamic. Class A Can be connected to GPRS service and GSM service (voice, SMS), using both at the same time. Such devices are known to be available today. Class B Can be connected to GPRS service and GSM service (voice, SMS), but using only one or the other at a given time. During GSM service (voice call or SMS), GPRS service is suspended, and then resumed automatically after the GSM service (voice call or SMS) has concluded. Most GPRS mobile devices are Class B. Class C Are connected to either GPRS service or GSM service (voice, SMS). Must be switched manually between one or the other service. A true Class A device may be required to transmit on two different frequencies at the same time, and thus will need two radios. To get around this expensive requirement, a GPRS mobile may implement the dual transfer mode (DTM) feature. A DTM-capable mobile may use simultaneous voice and packet data, with the network coordinating to ensure that it is not required to transmit on two different frequencies at the same time. Such mobiles are considered pseudo-Class A, sometimes referred to as "simple class A". Some networks are expected to support DTM in 2007. GPRS is new technology in which speed is a direct function of the number of TDMA time slots assigned, which is the lesser of (a) what the particular cell supports and (b) the maximum capability of the mobile device expressed as a GPRS Multislot Class UDP and TCP There are two protocols for data transmission over GPRS. One is UDP and the other is TCP. They are explained below: UDP User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. Using UDP, programs on networked computers can send short messages sometimes known as datagrams (using Datagram Sockets) to one another. UDP is sometimes called the Universal Datagram Protocol. The protocol was designed by David P. Reed in 1980 and formally defined in RFC 768. UDP does not guarantee reliability or ordering in the way that TCP does. Datagrams may arrive out of order, appear duplicated, or go missing without notice. Avoiding the overhead of checking whether every packet actually arrived makes UDP faster and more efficient, for applications that do not need guaranteed delivery. Time-sensitive applications often use UDP because dropped packets are preferable to delayed packets. UDP's stateless nature is also useful for servers that answer small queries from huge numbers of clients. Unlike TCP, UDP is compatible with packet broadcast (sending to all on local network) and multicasting (send to all subscribers). Common network applications that use UDP include: the Domain Name Service (DNS), streaming media applications such as IPTV, Voice over IP (VoIP), Trivial File Transfer Protocol (TFTP) and online games. UDP is a minimal message-oriented transport layer protocol that is currently documented in IETF RFC 768. In the Internet protocol suite, UDP provides a very simple interface between a network layer below (e.g., IPv4) and a session layer or application layer above. UDP provides no guarantees to the upper layer protocol for message delivery and a UDP sender retains no state on UDP messages once sent (for this reason UDP is sometimes called the Unreliable Datagram Protocol). UDP adds only application multiplexing and checksumming of the header and payload. If any kind of reliability for the information transmitted is needed, it must be implemented in upper layers. TCP The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. TCP is so central that the entire suite is often referred to as "TCP/IP." Whereas IP handles lower-level transmissions from computer to computer as a message makes its way across the Internet, TCP operates at a higher level, concerned only with the two end systems, for example your Web browser and a Web server. In particular, TCP provides reliable, in-order delivery of a stream of bytes from one program on one computer to another program on another computer. Besides the Web, other common applications of TCP include e-mail and file transfer. Among its management tasks, TCP controls message size, the rate at which messages are exchanged, and network traffic congestion. TCP provides a communication service at an intermediate level between an application program and the Internet Protocol (IP). That is, when an application programmer desires to send a large chunk of data across the Internet using IP, instead of breaking the data into IP-sized pieces and issuing a series of IP requests, the programmer can issue a single request to TCP and let TCP handle the IP details. IP works by exchanging pieces of information called packets. A packet is a sequence of bytes and consists of a header followed by a body. The header describes the packet's destination, which routers on the Internet use to pass the packet along—generally in the right direction—until it arrives at its final destination. The body contains the data which IP is transmitting. When IP is transmitting data on behalf of TCP, the contents of the IP packet body is TCP data. Due to network congestion, traffic load balancing, or other unpredictable network behavior, IP packets can be lost or delivered out of order. TCP detects these problems, requests retransmission of lost packets, rearranges out-of-order packets, and even helps minimize network congestion to reduce the occurrence of the other problems. Once TCP at the receiving end has finally reassembled a perfect copy of the large data chunk originally transmitted, it passes that single chunk up to the application program at the receiving end. Thus, TCP greatly simplifies the application programmer's network communication task. TCP is used extensively by many of the Internet's most popular application protocols and resulting applications, including the World Wide Web, E-Mail, File Transfer Protocol, Secure Shell, and some streaming media applications. However, because TCP is optimized for accurate delivery rather than timely delivery, TCP sometimes incurs relatively long delays (in the order of seconds) while waiting for out-of-order messages or retransmissions of lost messages, and it is not particularly suitable for real-time applications such as Voice over IP. For such applications, protocols like the Real time Transport Protocol (RTP) running over the User Datagram Protocol (UDP) are usually recommended instead. TCP is a reliable stream delivery service that guarantees delivery of a data stream sent from one host to another without duplication or losing data. Since packet transfer is not reliable, a technique known as positive acknowledgment with retransmission is used to guarantee reliability of packet transfers. This fundamental technique requires the receiver to respond with an acknowledgment message as it receives the data. The sender keeps a record of each packet it sends, and waits for acknowledgment before sending the next packet. The sender also keeps a timer from when the packet was sent, and retransmits a packet if the timer expires. The timer is needed in case a packet becomes lost or corrupt. TCP (Transmission Control Protocol) consists of a set of rules, i.e., the protocol, that are used with the Internet Protocol, the IP, to send data “in a form of message units” between computers over the Internet. At the same time that the IP takes care of handling the actual delivery of the data, the TCP takes care of keeping track of the individual units of data “packets” (or more accurately, “segments”) that a message is divided into for efficient routing through the net. For example, when an HTML file is sent to you from a Web server, the TCP program layer of that server takes the file as a stream of bytes and divides it into segments, numbers the segments, and then forwards them individually to the IP program layer. The IP program layer then turns each TCP segment into an IP packet by adding a header which includes (among other things) the destination IP address. Even though every packet has the same destination IP address, they can get routed differently through the network. When the client program in your computer gets them, the TCP stack (implementation) reassembles the individual segments and ensures they are correctly ordered as it streams them to an application. Mapping Top There are various mapping options available in represent location data on a map. Some are publicly available and some are paid ones. One can use their own digital maps as well to represent location data. GOOGLE MAPS Google Maps (for a time named Google Local) is a free web mapping service application and technology provided by Google that powers many map-based services including the Google Maps website, Google Ride Finder and embedded maps on third-party websites via the Google Maps API. It offers street maps, a route planner for bicycles, pedestrians (routes less than 6.2 miles) and cars, and an urban business locator for numerous countries around the world. A related product is Google Earth, a standalone program for Microsoft Windows, Mac OS X, and Linux which offers more globe-viewing features. Google Maps provides high-resolution satellite images for most urban areas in Canada and the United States (including Hawaii, Alaska, Puerto Rico, and the U.S.Virgin Islands) as well as parts of New Zealand, Australia, Egypt, France, Germany, Hong Kong, Hungary, Iran, Iceland, Italy, Ireland, Iraq, Japan, Jordan, Taiwan, the Bahamas, Bermuda, Kuwait, Mexico, the Netherlands, the United Kingdom, and many other countries. Google Maps also covers many cities including Moscow, Istanbul, and most of India. Various governments have complained about the potential for terrorists to use the satellite images in planning attacks. Google has blurred some areas for security (mostly in the United States), including the U.S. Naval Observatory area (where the official residence of the Vice President is located), and until recently, the United States Capitol and the White House (which formerly featured erased housetop). Other well-known government installations are visible including Areas 51 in the Nevada desert. With the introduction of an easily pannable and searchable mapping and satellite imagery tool, Google's mapping engine prompted a surge of interest in satellite imagery. Sites were established which feature satellite images of interesting natural and man-made landmarks, including such novelties as "large type" writing visible in the imagery, as well as famous stadia and unique earth formations. Although Google uses the word "satellite", most of the high-resolution imagery is aerial photography taken from airplanes rather than from satellites. Like many other Google web applications, Google Maps uses JavaScript extensively. As the user drags the map, the grid squares are downloaded from the server and inserted into the page. When a user searches for a business, the results are downloaded in the background for insertion into the side panel and map - the page is not reloaded. Locations are drawn dynamically by positioning a red pin (composed of several partially-transparent PNGs) on top of the map images. The technique of providing greater user-interactivity by performing asynchronous network requests with Javascript and XMLHttpRequest has recently become known as Ajax. Maps actually uses XmlHttpRequest sparingly, preferring a hidden IFrame with form submission because it preserves browser history. It also uses JSON for data transfer rather than XML, for performance reasons. These techniques both fall under the broad Ajax umbrella. The GIS (Geographic Information System) data used in Google Maps are provided by Tele Atlas, NAVTEQ, MapABC and MAPIT MSC, Malaysia while the small patches of high-resolution satellite imagery are largely provided by DigitalGlobe and its QuickBird satellite, with some imagery also from government sources. The main global imagery base called NaturalVue was derived from Landsat 7 imagery by MDA Federal (formerly Earth Satellite Corporation). This global image base provides the essential foundation for the entire application. As the Google Maps code is almost entirely JavaScript and XML, some end-users reverse-engineered the tool and produced client-side scripts and server-side hooks which allowed a user or website to introduce expanded or customised features into the Google Maps interface. Using the core engine and the map/satellite images hosted by Google, such tools can introduce custom location icons, location coordinates and metadata, and even custom map image sources into the Google Maps interface. The script-insertion tool Greasemonkey provides a large number of client-side scripts to customize Google Maps data. Combined with photo sharing websites such as Flickr, a phenomenon called "memory maps" emerged. Using copies of the Keyhole satellite photos of their home towns or other favorite places, the users take advantage of image annotation features to provide personal histories and information regarding particular points of the area. Google created the Google Maps API to facilitate developers integrating Google Maps into their web sites with their own data points. It is a free service, which currently does not contain ads, but Google states in their terms of use that they reserve the right to display ads in the future. By using the Google Maps API you can embed the full Google Maps on an external web site. Start by creating an API Key, it will be bound to the web site and directory you enter when creating the key. Creating your own map interface involves adding the Google JavaScript code to your page, and then using Javascript functions to add points to the map. When the API first launched, it lacked the ability to geocode addresses, requiring you to manually add points in (latitude, longitude) format. This has since been rectified. At the same time as the release of the Google Maps API, Yahoo! released their own Maps API. Both were released to coincide with the O'Reilly Web 2.0 Conference. Yahoo! Maps lacks international support, but included a geocoder in the first release. As of October 2006, Google Gadgets' Google maps implementation is much easier to use with just the need of one line of script. The drawback is that it is not as customizable as the full API. In late 2006, Yahoo began a campaign to upgrade their maps, to compete better with Google Local and other online map companies. Several of the maps used in a survey were similar to Google maps. Google Maps actively promotes the commercial use of their API. One of its earliest adopters at large scale are real estate mashup sites. Google's case study is about Nestoria, a property search engine in the UK and Spain. In late 2006, Google introduced a Java application called Googel Maps for Mobile, which is intended to run on any Java based phone or mobile device. Most, if not all, web based features are available from within the application. On November 28th, 2007, Google Maps for Mobile 2.0 was released. It introduced a GPS-like location service that does not require a GPS receiver. The "my location" feature works by utilizing the GPS location of the mobile device, if it is available. This information is supplemented by the software determining the nearest cell site. The software then looks up the location of the cell site using a database of known cell sites. The software plots a blue icon with a blue circle around the estimated range of the cell site based on the transmitter's rated power (among other variables). The estimate is refined using the strength of the cell phone signal to estimate how close to the cell site the mobile device is. As of July 10, 2008, this service is available for the following platforms: iPhone Windows Mobile Nokia / Symbian (S60 3rd edition only) Symbian OS (UIQ v3) BlackBerry Phones with Java-Platform (MIDP 2.0 and up), for example the Sony Ericsson K800i Palm OS (Centro and newer) MICROSOFT VIRTUAL EARTH Microsoft Virtual Earth is a geospatial mapping platform produced by Microsoft. It allows developers to create applications that layer location-relevant data on top of the Virtual Earth map imagery. This includes imagery taken from satellite sensors, aerial cameras (including "Bird's Eye" aerial imagery taken at 45 degree angle view to show building façades and entrances) as well as 3D city models and terrain. The Virtual Earth platform also provides a comprehensive point-of-interest database and the capability to search by business, person and address. Microsoft uses the Virtual Earth platform to power its Live Search Maps platform. Users can browse and search topographically-shaded street maps for many cities worldwide. Maps include certain points of interest built-in, such as metro stations, stadiums, hospitals, and other facilities. It is also possible to browse public user-created points of interest. Search can cover public collections, businesses or types of business, locations, or people. For some countries, like South Africa, and South Korea, Live Search Maps has data on highways and some arterial roads, but lacks local streets or alleys. There is also detailed map data available for several global cities in developing countries like Rio de Janeiro, Istanbul, and Mexico City. However, for such cities, the detail of the map decreases significantly as one moves outward from the city center. Live Search Maps has a tendency to mark certain unsigned three-digit Interstates in the United States, such as I-444 , I-110, , I-478, and the Interstate Highways in Alaska. Still other auxiliary Interstates, whose signs are not posted for various reasons, are labeled incorrectly as part of another Interstate. Examples are I-695 (DC), which is labeled as part of I-295 (DC), and I-878, which is labeled as I-678. Live Search Maps also includes several terabytes of satellite and aerial imagery. In many areas, maximum resolution is approximately 4.5 pixels per meter. Elsewhere, especially in the most remote areas of the world, top resolution is a few orders of magnitude less. Users may toggle labels on or off, choosing whether to see the ground as it would appear from an airplane versus closer to how it would appear on a map. List of countries that have detailed satellite images: United States Canada United Kingdom Germany Italy Australia New Zealand Japan India In over 100 cities in the United States and in over 80 European locations, a bird's-eye view offers aerial photos from four angles. These Pictometry images are much more detailed than the aerial views from directly above buildings. Signs, advertisements, pedestrians, and other objects are clearly visible in many bird's eye views. The 3D Maps feature lets user see buildings in 3D, with the added ability to rotate and tilt the angle in addition to panning and zooming. To attempt to achieve near-photorealism, all 3D buildings are textured using composites of aerial photography. To view the 3D maps, users must install a plugin, then enable the "3D" option on "Virtual Earth". In addition to exploring the maps using a mouse and keyboard, it is possible to navigate the 3D environment using an Xbox 360 controller or another game controller in Windows Vista or Windows XP. As of April 2007, users may also use 3Dconnexion's SpaceNavigator input device. Currently, roughly 68 cities worldwide may be viewed in 3D, including most of the major cities in the United States and a few cities in Canada, the United Kingdom, and France. Some additional cities have had a select few important landmarks modelled in 3D, such as the Colosseum in Rome. Terrain data is available for the entire world. It is also possible to use a simple 3D modelling program called Virtual Earth - 3DVIA to add one's own models to the 3D map. The following is a partial list of cities that have most areas rendered in 3D: United States Atlanta, Augusta, Aurora-Naperville, Baton Rouge, Birmingham, Boston, Buffalo, Cape Coral, Cedar Rapids, Chattanooga, Chicago, Cleveland, Cincinnati, Coral Springs, Dallas-Fort Worth, Denver, Detroit, Huntsville, Indianapolis, Jackson, Jacksonville, Joliet, Kansas City, Knoxville, Las Vegas, Los Angeles, Louisville, Miami, Milwaukee, Minneapolis, Mobile, Montgomery, Nashville, New Orleans, New York, Orlando, Philadelphia, Phoenix, Portland (OR), Redmond, Rockford, Sacramento, San Diego, San Francisco, Savannah, Seattle, Shreveport, St. Louis, St. Petersburg, Tacoma, Tallahassee, Tampa, Tucson, West Palm Beach. Canada Calgary, Edmonton, Hamilton, Montreal, Ottawa, Quebec, Toronto United Kingdom Brighton, Bristol, Cardiff, Eastbourne, Gloucester, Liverpool, Northampton, Norwich, Plymouth, Swindon, Wolverhampton France Toulouse, Vannes Japan Tokyo Austria Vienna CLEARFLOW Microsoft announced in March 2008 that it will be releasing its latest software technology called “ClearFlow”. It is a Web-based service for driving directions available on Live.com in 72 cities across the U.S. The tool took five years for Microsoft’s Artificial Intelligence team to develop. ClearFlow provides real-time traffic data to help drivers avoid traffic congestion. Differing from Yahoo! Maps, Google Maps and Mapquest, ClearFlow not only gives information for alternative routes, but supplies traffic conditions on city streets adjacent to highways.[11] Clearflow anticipates traffic patterns, while taking into account sporting/arena events, time of day and weather conditions, and then reflects the back ups and their consequential spill over onto city streets. Often, ClearFlow found it may be faster to stay on the highway instead of seeking alternative side street routes, which involve traffic lights and congestion as well. According to U.S Microsoft employee and artificial intelligence expert, Eric Horvitz, “…ClearFlow would be integrated into Live Search Mobile and other Microsoft mobile applications, including in-car navigation and personal navigation devices.” Clearflow will be available at no cost. The one draw back of Clearflow is that it offers no real-time updates regarding highway and road closures or accidents. YAHOO MAPS Yahoo! Maps is a free online mapping portal provided by Yahoo!. The main Yahoo! Maps site offers street maps and driving directions for the United States and Canada. It has the following notable features: Address Book: Registered Yahoo! users can store a list of commonly used street addresses, making it unnecessary to type them in again. A recently entered address can be quickly recalled by selecting one from a drop-down list. Live Traffic: Traffic incident markers and current highway conditions can be viewed on the map. Point of Interest Finder: SmartView (tm) can be used to find businesses and other points of interest near the current location, with clickable icons that supply an address, a telephone number, and links for more information. Driving Directions: Driving directions can be displayed on a map or in printable form, with optional turn-by-turn maps, or as simple text. Links to driving directions can be e-mailed, and text directions sent to mobile phones. A new and improved Yahoo! Local Maps has been recently made available. It offers maps with significantly more interactivity for broadband users. It is written using AJAX, leveraging Rich Internet Application techniques. Some features: Draggable maps: The current map view can be manipulated by dragging it with the mouse or tapping the arrow keys. Zoom level can be controlled via the mouse scroll wheel, "Page Up"/"Page Down" keys, or the map's zoom bar. Multi-point driving directions: Multiple addresses can be entered and manually reordered for complex driving directions. Find On The Map: A local search by business name or category can be typed into the "Find On The Map" box to locate it in the current map view. A list of clickable point of interest categories is also available. The results can be further refined by user rating, or related category. Widgets: A number of widgets over the map include a navigator widget, map type (map, satellite & hybrid) controller and a zoom level control. Satellite Imagery: Labelled (hybrid) and unlabelled satellite imagery is available world-wide. Overview map: Collapsible overview map provides context, with draggable grey area controlling the main map view. International Coverage: Outside the US and Canada, Yahoo! Maps Beta can recognize city, province, and country names, and provide a small-scale map or satellite views. Right click to set waypoint: an origin, destination, or midpoint can be set by right-clicking on the desired location on the map. Draggable markers: Any marker can be dragged to the 'Get Map' text entry area to add that location to a route. Live traffic, address book, and send to phone features are also available. Developers can embed Yahoo! Maps into their own web pages (to create a mashup) through the Yahoo! Maps Developer APIs. Many exciting new web sites have come about recently by displaying content from other sources on top of maps provided by the various mapping portals (the Google Maps API getting the most publicity). The Yahoo! Maps APIs come in three basic flavors: The Flash APIs, that use the Adobe Flash platform. Three variations, allowing the developer to write in JavaScript, ActionScript, or Adobe Flex 1.5, are available. The Ajax API, for interactive maps that use capabilities inherent in web browsers, without using the Flash plug-in. Ajax applications are written in JavaScript. The "Simple" API. The Simple API is basically an XML data format, an extension of GeoRSS, for displaying point of interest data on top of Yahoo!'s main map site. The Flash and Ajax APIs also support display of GeoRSS formatted data. Yahoo! offers a number of low-level APIs to support maps, for geocoding, getting a map image, searching for a local business, or retrieving traffic information. Some other Yahoo! services, such as Flickr and Upcoming.org, have their content available through web services, with interesting potential for mashups. Common Uses Top Vehicle tracking systems are commonly used by fleet operators for fleet management functions such as routing, dispatch, on-board information and security. Other applications include monitoring driving behavior, such as an employer of an employee, or a parent with a teen driver. Vehicle tracking systems are also popular in consumer vehicles as a theft prevention and retrieval device. Police can simply follow the signal emitted by the tracking system and locate the stolen vehicle. When used as a security system, a Vehicle Tracking System may serve as either an addition to or replacement for a traditional car alarm. The existence of vehicle tracking device then can be used to reduce the insurance cost, because the loss-risk of the vehicle drops significantly. Vehicle tracking systems are an integrated part of the “layered approach” to vehicle protection, recommended by the National Insurance Crime Bureau (NICB) to prevent motor vehicle theft. This approach recommends four layers of security based on the risk factors pertaining to a specific vehicle. Vehicle Tracking Systems are one such layer, and are described by the NICB as “very effective” in helping police recover stolen vehicles. Some vehicle tracking systems integrate several security systems, for example by sending an automatic alert to a phone or email if an alarm is triggered or the vehicle is moved without authorization. Major Markets Top Vehicle tracking can be used in the following scenarios: Stolen Vehicle Recovery: Both consumer and commercial vehicles can be outfitted with RF or GPS units to allow police to do tracking and recovery. In the case of LoJack, the police can activate the tracking unit in the vehicle directly and follow tracking signals. Fleet Management: When managing a fleet of vehicles, knowing the real-time location of all drivers allows management to meet customer needs more efficiently. Whether it is delivery, service or other multi-vehicle enterprises, drivers now only need a mobile phone with telephony or Internet connection to be inexpensively tracked by and dispatched efficiently. Asset Tracking: Companies needing to track valuable assets for insurance or other monitoring purposes can now plot the real-time asset location on a map and closely monitor movement and operating status. Field Service Management: Companies with a field service workforce for services such as repair or maintenance, must be able to plan field workers’ time, schedule subsequent customer visits and be able to operate these departments efficiently. Vehicle tracking allows companies to quickly locate a field engineer and dispatch the closest one to meet a new customer request or provide site arrival information. Field Sales: Mobile sales professionals can access real-time locations. For example, in unfamiliar areas, they can locate themselves as well as customers and prospects, get driving directions and add nearby last-minute appointments to itineraries. Benefits include increased productivity, reduced driving time and increased time spent with customers and prospects. Trailer Tracking: Haulage and Logistics companies often operate lorries with detachable load carrying units. The part of the vehicle that drives the load is know as the cab and the load carrying unit is known as the trailer. There are different types of trailer used for different applications, e.g., flat bed, refrigerated, curtain sider, box container. Wildlife Tracking: These tracking systems can be modified and used for tracking of wildlife by fitting a tracking device on their neck which logs their location and transmits via sms or GPRS after a predetermined frequency. GPS wildlife tracking is a process whereby biologists, scientific researchers or conservation agencies can remotely observe relatively fine-scale movement or migratory patterns in a free-ranging wild animal using the Global Positioning System and optional environmental sensors or automated data-retrieval technologies such as Argos satellite uplink, mobile data telephony or GPRS and a range of analytical software tools. A GPS-enabled device will normally record and store location data at a pre-determined interval or on interrupt by an environmental sensor. These data may be stored pending recovery of the device or relayed to a central data store or internet-connected computer using an embedded cellular (GPRS), radio, or satellite modem. The animal's location can then be plotted against a map or chart in near real-time or, when analysing the track later, using a GIS package or custom software. While GPS tracking devices may also be attached to domestic animals such as pets, pedigree livestock and working dogs, and similar systems are used in fleet management of vehicles, wildlife tracking can place additional constraints on size and weight and may not allow for post-deployment recharging or replacement of batteries or correction of attachment. As well as allowing in-depth study of animal behaviour and migration, the high-resolution tracks available from a GPS-enabled system can potentially allow for tighter control of animal-borne communicable diseases such as the H5N1 strain of avian influenza. Fleet control. For example, a delivery or taxi company may put such a tracker in every of its vehicles, thus allowing the staff to know if a vehicle is on time or late, or is doing its assigned route. The same applies for armored trucks transporting valuable goods, as it allows to pinpoint the exact site of a possible robbery. Stolen vehicle searching. Owners of expensive cars can put a tracker in it, and "activate" them in case of theft. "Activate" means that a command is issued to the tracker, via SMS or otherwise, and it will start acting as a fleet control device, allowing the user to know where the thieves are. Animal control. When put on a wildlife animal (e.g. in a collar), it allows scientists to study its activities and migration patterns. Vaginal implant transmitters are used to mark the location where pregnant females give birth. Animal tracking collars may also be put on domestic animals, to locate them in case they get lost. Race control. In some sports, such as gliding, participants are required to have a tracker with them. This allows, among other applications, for race officials to know if the participants are cheating, taking unexpected shortcuts or how far apart they are. This use has been featured in the movie "Rat Race", where some millionaires see the position of the racers in a wall map. Espionage/surveillance. When put on a person, or on his personal vehicle, it allows the person monitoring the tracking to know his/her habits. This application is used by private investigators, and also by some parents to track their children. Internet Fun. Some Web 2.0 pioneers have created their own personal web pages that show their position constantly, and in real-time, on a map within their website. These usually use data push from a GPS enabled cell phone. Technologies Used in Vehicle Tracking Top GEOCODING It is the process of assigning geographic identifiers (e.g., codes or geographic coordinates expressed as latitude-longitude) to map features and other data records, such as street addresses. Media can also be geocoded, for example where a picture was taken, IP addresses, and anything that has a geographic component. With geographic coordinates the features can be mapped and entered into Geographic Information Systems. A geocoder is a piece of software or a (web) service that helps in this process. A simple method of geocoding is address interpolation. This method makes use of data from a street geographic information system where the street network is already mapped within the geographic coordinate space. Each street segment is attributed with address ranges (e.g. house numbers from one segment to the next). Geocoding takes an address, matches it to a street and specific segment (such as a block, in towns that use the "block" convention). Geocoding then interpolates the position of the address, within the range along the segment. Take for example: 742 Evergreen Terrace Let's say that this segment (for instance, a block) of Evergreen Terrace runs from 700 to 799. Even-numbered addresses would fall on one side (e.g. west side) of Evergreen Terrace, with odd-numbered addresses on the other side (e.g. east side). 742 Evergreen Terrace would (probably) be located slightly less than halfway up the block, on the west side of the street. A point would be mapped at that location along the street, perhaps offset some distance to the west of the street centerline. However, this process is not always as straightforward as in this example. Difficulties arise when: Distinguishing between ambiguous addresses such as 742 Evergreen Terrace and 742 W Evergreen Terrace. Geocoding new addresses for a street that is not yet added to the geographic information system database. While there might be 742 Evergreen Terrace in Springfield, there might also be a 742 Evergreen Terrace in Shelbyville. Asking for the city name (and state, province, country, etc. as needed) can solve this problem. Some situations require use of postal codes or district name for disambiguation. For example, there are multiple 100 Washington Streets in Boston, Massachusetts because several cities have been annexed without changing street names. Finally, several caveats on using interpolation. The typical attribution of a street segment assumes that all "even" numbered parcels are on one side of the segment, and all "odd" numbered parcels are on the other. This is often not true in real life. Interpolation assumes that the given parcels are evenly distributed along the length of the segment. This is almost never true in real life; it is not uncommon for a geocoded address to be off by several thousand feet. Segment Information (esp. from sources such as TIGER) includes a maximum upper bound for addresses and is interpolated as though the full address range is used. For example, a segment (block) might have a listed range of 100-199, but the last address at the end of the block is 110. In this case, address 110 would be geocoded to 10% of the distance down the segment rather than near the end. Most interpolation implementations will produce a point as their resulting "address" location. In reality, the physical address is distributed along the length of the segment, i.e. consider geocoding the address of a shopping mall - the physical lot may run quite some distance along the street segment (or could be thought of as a two-dimensional space-filling polygon which may front on several different streets - or worse, for cities with multi-level streets, a three-dimensional shape that meets different streets at several different levels) but the interpolation treats it as a singularity. A very common error is to believe the accuracy ratings of a given map's geocodable attributes. Such "accuracy" currently touted by most vendors has no bearing on an address being attributed to the correct segment, being attributed to the correct "side" of the segment, nor resulting in an accurate position along that correct segment. With the geocoding process used for U.S. Census TIGER datasets, 5-7.5% of the addresses may be allocated to a different census tract, while 50% of the geocoded points might be located to a different property parcel. Because of this, it is quite important to avoid using interpolated results except for non-critical applications, such as pizza delivery. Interpolated geocoding is usually not appropriate for making authoritative decisions, for example if life safety will be impacted by that decision. Emergency services, for example, do not make an authoritative decision based on their interpolations; an ambulance or fire truck will always be dispatched regardless of what the map says. Other means of geocoding might include locating a point at the centroid (center) of a land parcel, if parcel (property) data is available in the geographic information system database. In rural areas or other places lacking high quality street network data and addressing, GPS is useful for mapping a location. For traffic accidents, geocoding to a street intersection or midpoint along a street centerline is a suitable technique. Most highways in developed countries have mile markers to aid in emergency response, maintenance, and navigation. It is also possible to use a combination of these geocoding techniques - using a particular technique for certain cases and situations and other techniques for other cases. The proliferation and ease of access to geocoding (and reverse-geocoding) services raises privacy concerns. For example, in mapping crime incidents, law enforcement agencies aim to balance the privacy rights of victims and offenders, with the public's right to know. Law enforcement agencies have experimented with alternative geocoding techniques that allow them to mask some of the locational detail (e.g., address specifics that would lead to identifying a victim or offender). As well, in providing online crime mapping to the public, they also place disclaimers regarding the locational accuracy of points on the map, acknowledging these location masking techniques, and impose terms of use for the information. Reverse GEOCODING Reverse geocoding is the process of finding a place name from a given latitude and longitude.Once you have generated latitude and longitude information for an image, you can right click on the image and use the Location names menu to tell Geotag to search for location names for one or more images. Geotag does this by sending a request to geonames.org, a web site that offers lookups as a free service. Many thanks to the good people at geonames.org By default Geotag asks only for the nearest place name geonames knows, but you can use the Settings dialog to customize this. By specifying a "search radius" (in kilometers or miles depending on your settings) Geotag will request location names within this radius. By specifying the "Number of results" you can limit how many location names are retrieved within the search radius. You can then select one of the location names retrieved by right clicking on the image and selecting Location names->Select. If geonames.org knows more than one name for the same location, Geotag will display all known names in a sub-menu for you to choose from. Another way of getting location names is finding the names of Wikipedia articles that have been tagged with coordinates close to the image coordinates. This can help if the image location is a point of interest (with Wikipedia article) far away from the next populated place. Also in populated, touristy places you might find that the subject of your image has a Wikipedia entry with coordinates (works great in London). Luckily geonames.org offers such a service. Unfortunately it only supplies the title of the Wikipedia article, but not (yet - I'm told) the country, city or region. That's why, when you select a Wikipedia location name, the region and country are left unchanged. Wikipedia location names are easily recognizable by the little 'W' icon next to the name. If you select a new place name for an image, Geotag does the following: If the selected location is a Wikipedia entry, only the location name will be updated. The city, province and country will remain unchanged. If the selected location is a populated place, the city name, province and country will be updated and the location name is not changed. Otherwise the location name, province and country will be updated and the city name is not changed. If anyone has a better suggestion for handling this, please let me know. It's not perfect, but I think it's a reasonable solution. You can always manually edit Geotag's suggestions. A third way of giving your picture a location, region and country name is to click on the corresponding field in the images table and enter the names manually. Not very high-tech, but it works.