Global Positioning System - Coursework Example

Working Draft 2 **The rest will follow in a few hours** GPS Global Positioning System 1. Introduction GPS or Global Position System is commonly known as a technology that has the ability to find geography position using tri-lateration of multiple satellites. In other words, users of GPS can use information from four satellites to calculate their position on anywhere on earth. Although GPS signal was degraded for security purpose such as military threats, GPS was used for many useful commercial applications, including pavement and asset management, vehicle tracking and navigations systems. However, in year 2000, this selective availability of signal degradation was removed and GPS accuracy increased. Moreover, GPS receivers have been miniaturized thus prices have become economical and affordable to many. The following sections would discus the technology behind GPS, its various functions, commercial applications, cost effectiveness, security and privacy issues, and the future direction of GPS. 2. Aims and Objectives The aim of this report is to provide an analysis of a popular information systems technology that is widely used by successful commercial companies. This includes discussions on the technology behind GPS, its commercial applicability, and the benefits of such new and unique technology. The objectives of this report are to provide up-to-date information on the selected topic. Conduct a thorough research that can provide clear and well-organized facts about GPS and improve understanding of the benefits and disadvantages of GPS commercial applications. 3. Plan of the Report Will follow 4. Literature Review 4.1 Introduction to RFID GPS is an acronym for Global Positioning System, a technology that allows the location of a receiver on the planet to be determined in terms of latitude and longitude with a higher degree of accuracy (Collura 2004, p.16). Although GPS was originally designed as a military system, GPS had helped revolutionised surveying and navigation fields and it is now being used in civil and commercial applications (El-Rabbany 2002, p.10). Unlike compass that needs landmark bearings to establish a person’s position, GPS can provide position without a landmark which can be very helpful in featureless terrain or wilderness (Burns 2004, p.100). The trucking industry began using GPS as part of mobile communications and tracking solutions to improve fleet management and delivery of freight in the late 1980s (Genson & Kerezman 2006, p.180). Today, consumer GPS receivers are typically used for land navigation and those that are less portable type receivers or the commercial models found their use with airplanes, boats, and land vehicles (McNamara 2004, p.3). 4.2 The Technology Behind GPS In 1978, the U.S. Department of Defence launched the first GPS satellite but it was only in the mid 1990s that it became fully operational (Xu 2007, p.14). GPS is a spaced-based radio positioning system that can provide highly accurate position, velocity, and time information (Clarke 1998, p.1). According the Xu (2007, p.14), the GPS constellation is composed of twenty-four satellites in six orbital planes with four satellites in each plane. The ascending nodes of the orbital planes are equally spaced by 60 degrees while the orbital planes are inclined 55 degrees. Every GPS satellite is in a nearly circular orbit with a semi-major axis of 26,578km and a period of approximately 12 hours. The satellite continuously orients themselves to ensure that their solar panels maintain its position towards the Sun, and their antennas toward the Earth. Each satellite carries four atomic clocks that generate the fundamental L-band frequency at 10.23 megahertz. Meanwhile, all base stations on earth monitoring the satellites have precise cesium clocks and receivers to determine the broadcast ephemerides or (table of values that gives the position of astronomical objects) and to model the satellite clocks. While the base stations transmit the ephemerides and clock adjustments, the satellites in turn use these transmitted information to update the signals that they send to GPS receivers. GPS systems are not only about positions but clock time because major error in reading would occur if the receiver clock is not in sync with the satellite clock (Strang & Borre 1997, p.8). All GPS receivers have an almanac programmed into their computer, which tells them where each satellite is at any given time. The almanac is a data file that contains information of orbits and clock corrections of all satellite. The GPS receivers detect, decode, and process the signals received from the satellites to create the data of the code, phase, and Doppler observables. The GPS receiver’s internal software process the real time data with the single point positioning method and output the information to the user (Xu 2007, p.15). 4.3 Physical Asset Tracking and Management Two of the most popular enterprise application of GPS are asset tracking and fleet management (Broida p.171). For instance, according to Stakutis & Webster (2005, p.18), wireless and GPS are currently being use to guide and drive tractors in real time. The reason for such deployment is the ability of GPS to accurately pinpoint the exact location of tractors in the field. In large farms, tilling operations when done manually often times result to nonparallel tracking which could over tilled some portions of the field. Obviously, repeated tilling on the same area is a waste of time. With GPS, the tractors are actually guided and turning automatically resulting to a more accurate tilling even at night. In a study released by ABI in 2003, automotive and asset tracking account for nearly 50% of the GPS global sales (Information Gatekeeper Inc. 2003, p.10). It is widely used to track assets such as vehicles and other expensive equipment (Jones & Chung 2007, p.320). For instance, GPS installed on a truck would make it easy to find when it breaks down thus it is possible to get the shipment moving again in the shortest time. The GPS receiver is capable of sending not only its location but information about the cargo being shipped (Jones & Chung 2007, p.320). The General Motor’s OnStar service provides navigation, information and roadside assistance services to owners of luxury cars. The GPS technology inside these cars can be used to find these cars when stolen (Cavoukian & Hamilton 2002, p.186). Other companies such as AirIQ and Fleetrak also offer companies management of their moving assets such as tracking a fleet of trucks over the Internet. For instance, Cam-Scott, a transport company in Canada uses the service to track 84 trucks and if any truck miss its course, speeds, overheats, or stolen, the company would be alerted immediately. Cam-Scott can also ask AirIQ to remotely open the locks if the driver accidentally locks his key in the truck cabin (Cavoukian & Hamilton p.186). 4.4 Cost Effectiveness In late 1970s, GPS receivers were highly specialised and therefore extremely expensive. A five-channel GPS set in 1979 cost around $116,000 but a few years later in the mid 1980s, it has went down to $47,000 (Carus 1992, p.59). The reason for the cost reduction was linked to the decreasing cost of electronic systems. Since then, the cost of GPS receivers continued to decrease and the unit price went $450 for a single purchase and could drop up to $225 for volume purchase in the early 1990s (Carus 1992, p.60). GPS surveying is normally done in less cost and quicker that conventional surveying (Thompson & Sorvig 2000, p.34). The results of GPS survey are digital and can be read by computers for mapping and analysis. For instance, if a construction design is digital, drawings can be loaded into the GPS field unit to assist the surveyor in staking. According to Thompson & Sorvig (2000, p.34), it is easier to draw as-built drawings with GPS and certainly more cost-effective and powerful tool. Since GPS, compared to traditional survey methods, does not require line-of-sight between adjacent points and can be use in any weather. According to Czemiak & Reilly (1998, p.25), many governments have taken advantage of the relatively low cost of GPS surveys to densify network control stations in their area. The estimates of effectiveness over traditional techniques range from 6:1 to 20:1. Moreover, the increase accuracy is an additional benefit of GPS when use for densification work. Due to strong competition, GPS receiver prices in the marketplace are as low as $100 to over $10,000 depending on the features (Sweet 2003, p.61). 4.5 Commercial Applications GPS provides unprecedented accuracy and timing information as a free service, available to anyone with relatively inexpensive receiving equipment. Commercial GPS systems are useful for manufacturers tracking the status of deliveries, farmers improving land management applications, outdoor enthusiasts, police keeping tabs on dangerous criminals on parole, rental car options assisting customers to locate their destinations, schools providing advance notice to students as buses approach their respective bus stops, and even for fishermen finding their favourite fishing holes. The number of navigation applications continues to grow rapidly, and the reason is the highly accurate timing signal broadcast from each GPS satellite (Armistead 2004, p.121). Aside from fleet management and expensive asset tracking, GPS is being use in location tracking of children (Peterson 2003, p.100). For instance, US companies like Wherify Wireless and GlobeXplorer offers parents services for child safety or personal protection. They product, GPS Personal Locator for Children is an integrated timepiece/GPS receiver worn by children on their wrist. Parents who are also Web-savvy can find their child by just dialling an 800-number or long onto wwww.wherify.com. Immediately, the company would map the child’s location and provide the closest street address. Similarly, but more innovative, GlobeXplorer offers aerial imagery over the internet. The map is centred on the child’s location where parents can zoom in for a closer look or explore the area by zooming or panning (Peterson 2003, p.101). 4.6 GPS Security and Limitations GPS like any other technology has its problems and limitations. For instance, GPS is not self-contained and the user must be able to have clear view of the GPS satellites. Moreover, satellite visibility may be obstructed by intervening buildings, foliage, mountains, bridges, and tunnels. This is because according to Jekeli (2000, p.258), the carrier signal that the satellite transmits and that conveys positioning codes and the navigation message has a wavelength only 19cm long and so will be severely attenuated even with light to moderate foliage and completely blocked by most larger structures. For this reason, direct underwater applications of GPS are completely impossible (Jekeli 2000, p.258). Another obvious disadvantage of commercial GPS handheld receivers is its small screens that are difficult to see particularly on a moving vehicle. Secondly, the buttons are too small and seems not applicable for use on moving platforms. Thirdly, GPS unit have built-in antenna thus location of the unit can significantly affect the signal. For optimal performance, a GPS receiver must be held nearly vertical to enable the antenna to get the best reception. More importantly, the antenna must have a clear view of the sky and any obstruction would affect the quality of the signal (Sweet 2003, p.61). 5. Conclusion Will follow 6. Current Status/Future Direction GPS applications have quickly multiplied to the point where the system is now often described as “global utility” (Sadeh p.359). Almost certain, the GPS will likely to continue its rapid growth in the commercial sector in the foreseeable future. However, there are still a number of issues associated with GPS and these include the various ways in which the system can be jammed, liability issues, responsibility for operating the system, funding for the base stations, how precise the positioning data should be, and what type of users should be authorized access to the most precise signals (Sadeh 2002, p.360). According to Broida (2004, p.14), although GPS technology has been around for many years, the technology is still in its infancy. The number of recent applications of GPS only demonstrate how people is just starting to take full advantage of it. For instance, the LX200GPS telescope that is equipped with a built-in GPS receiver that enables telescope alignment, which is obviously just as the starting point for accurate stargazing. GPS is also just starting to appear on portable path finding devices for the blind and it is still have a long way to go for this application. In farming and other related use, GPS in the near future can make “precision farming” really accurate by identifying location of farm equipment with remarkable precision. The advantage of being precise within centimetres according to Virchow & Braun (2001, p.283), is that location of soil samples and the laboratory results can be compared to a soil map. Moreover, tillage adjustments can be made to allow for various conditions across the field and yield data can be monitored and recorded by simply moving across the field. Using GPS together with digital drainage map, the farmer can apply pesticides in safer manner and in a more suitable ways. Crime mapping for law enforcement is also one of the future directions of GPS since it can help provide data accessibility for patrol officers and the public, and crime forecasting (Green 2006, p.326). 7. References Will follow Read More

2 The Technology Behind GPS In 1978, the U.S. Department of Defence launched the first GPS satellite but it was only in the mid 1990s that it became fully operational (Xu 2007, p.14). GPS is a spaced-based radio positioning system that can provide highly accurate position, velocity, and time information (Clarke 1998, p.1). According the Xu (2007, p.14), the GPS constellation is composed of twenty-four satellites in six orbital planes with four satellites in each plane. The ascending nodes of the orbital planes are equally spaced by 60 degrees while the orbital planes are inclined 55 degrees.

Every GPS satellite is in a nearly circular orbit with a semi-major axis of 26,578km and a period of approximately 12 hours. The satellite continuously orients themselves to ensure that their solar panels maintain its position towards the Sun, and their antennas toward the Earth. Each satellite carries four atomic clocks that generate the fundamental L-band frequency at 10.23 megahertz. Meanwhile, all base stations on earth monitoring the satellites have precise cesium clocks and receivers to determine the broadcast ephemerides or (table of values that gives the position of astronomical objects) and to model the satellite clocks.

While the base stations transmit the ephemerides and clock adjustments, the satellites in turn use these transmitted information to update the signals that they send to GPS receivers. GPS systems are not only about positions but clock time because major error in reading would occur if the receiver clock is not in sync with the satellite clock (Strang & Borre 1997, p.8). All GPS receivers have an almanac programmed into their computer, which tells them where each satellite is at any given time.

The almanac is a data file that contains information of orbits and clock corrections of all satellite. The GPS receivers detect, decode, and process the signals received from the satellites to create the data of the code, phase, and Doppler observables. The GPS receiver’s internal software process the real time data with the single point positioning method and output the information to the user (Xu 2007, p.15). 4.3 Physical Asset Tracking and Management Two of the most popular enterprise application of GPS are asset tracking and fleet management (Broida p.171). For instance, according to Stakutis & Webster (2005, p.18), wireless and GPS are currently being use to guide and drive tractors in real time.

The reason for such deployment is the ability of GPS to accurately pinpoint the exact location of tractors in the field. In large farms, tilling operations when done manually often times result to nonparallel tracking which could over tilled some portions of the field. Obviously, repeated tilling on the same area is a waste of time. With GPS, the tractors are actually guided and turning automatically resulting to a more accurate tilling even at night. In a study released by ABI in 2003, automotive and asset tracking account for nearly 50% of the GPS global sales (Information Gatekeeper Inc. 2003, p.10).

It is widely used to track assets such as vehicles and other expensive equipment (Jones & Chung 2007, p.320). For instance, GPS installed on a truck would make it easy to find when it breaks down thus it is possible to get the shipment moving again in the shortest time. The GPS receiver is capable of sending not only its location but information about the cargo being shipped (Jones & Chung 2007, p.320). The General Motor’s OnStar service provides navigation, information and roadside assistance services to owners of luxury cars.

The GPS technology inside these cars can be used to find these cars when stolen (Cavoukian & Hamilton 2002, p.186). Other companies such as AirIQ and Fleetrak also offer companies management of their moving assets such as tracking a fleet of trucks over the Internet. For instance, Cam-Scott, a transport company in Canada uses the service to track 84 trucks and if any truck miss its course, speeds, overheats, or stolen, the company would be alerted immediately.

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