National Academies Press: OpenBook

The Global Positioning System: A Shared National Asset (1995)

Chapter: Current and Future Applications and Requirements

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Suggested Citation:"Current and Future Applications and Requirements." National Research Council. 1995. The Global Positioning System: A Shared National Asset. Washington, DC: The National Academies Press. doi: 10.17226/4920.
Page 38
Suggested Citation:"Current and Future Applications and Requirements." National Research Council. 1995. The Global Positioning System: A Shared National Asset. Washington, DC: The National Academies Press. doi: 10.17226/4920.
Page 39
Suggested Citation:"Current and Future Applications and Requirements." National Research Council. 1995. The Global Positioning System: A Shared National Asset. Washington, DC: The National Academies Press. doi: 10.17226/4920.
Page 40

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GPS APPLICATIONS AND REQUIREMENTS 38 The presence of SA affects the acceptance of GPS by recreational boaters and some commercial users, and limits the ability of the Coast Guard's DGPS service to provide important safety-related information to its users. LAND TRANSPORTATION APPLICATIONS The civil land transportation sector of the nation's economy has generally been slow to adopt high technologies from other sectors such as aerospace or electronics. Recently, however, this trend is beginning to change due to an increased focus on initiatives such as the Intelligent Transportation System (ITS), which adapt defense-related technologies for uses in the civilian community.28 More specifically, land transportation applications of GPS are growing rapidly, triggered by ever cheaper and more sophisticated equipment, an accelerated maturation of technology, widely available differential augmentations, and competition for economic and environmental responsiveness. All modes of land transportation, including trains, trucks, automobiles, all- terrain vehicles, bicycles, backcountry skiers, hikers, and even pedestrians, have applications in which safety, position-location, and navigation are important, and have users who are therefore willing to use low-cost GPS, DGPS augmentations, or other comparable systems. Current and Future Applications and Requirements The trucking and railroad industries are currently the dominant land users of GPS for vehicle location and navigation, in part for reasons of competitive advantage in meeting the needs of just-in-time manufacturers and goods distributors. As on-time delivery becomes increasingly important to U.S. manufacturers and distributors, the trucking and rail industries and the international freight industry will require the ability to locate not only their vehicles or shipping containers, but also the components of their cargo when it consists of divisible elements, such as the packages handled by United Parcel Service or Federal Express. This must be accomplished with ever-greater accuracy and in near real-time. The tentative quantitative requirements for these GPS applications are listed in Table 2-6. One of the largest near-term markets for GPS will probably be for automobile and light truck navigation and position-location. This market can evolve in a number of ways, since the automobile is used for a variety of purposes. On-board GPS and CD-ROM map systems are already being utilized by several rental car agencies, and at least one major U.S. automobile manufacturer already offers a GPS-based navigation system to its customers as 28 ITS was formerly known as the Intelligent Vehicle/Highway System (IVHS). The name was changed to recognize the multi-modal nature of transportation.

GPS APPLICATIONS AND REQUIREMENTS 39 an option.29 It also is estimated that over half a million automobiles owned and operated in Japan already carry a GPS-based automobile navigation system.30 Although the final systems architecture and standards for the nation's ITS program have yet to be determined, the FHWA (Federal Highway Administration) anticipates that GPS will be an important component.31 Potential ITS applications for GPS, in addition to vehicle navigation and position-location, include collision avoidance and control, vehicle command and control, automated bus stops, automated toll collection, accident data collection, a number of commercial vehicle regulatory activities, and ITS infrastructure management. Tentative requirements for these applications are included in Table 2-6. GPS can also be used for the automatic guidance of farm vehicles engaged in precision farming. Also known as prescription farming, or site-specific crop management, precision farming gives the farmer the ability to apply precise amounts of fertilizer and pesticide to exact field locations based on the type of crop planted and the soil composition, potentially improving both the efficiency and cost-effectiveness of these operations. The positioning and navigation accuracy required for precision farming, as shown in Table 2-6, can only be met with local-area DGPS. Much of the growth in the so called low-end, personal GPS receiver market can be attributed to transportation-related recreation activities involving both vehicles and pedestrians. Examples include "off- roading" with four-wheel drive vehicles, back-country skiing, mountain climbing, bicycling, hiking, and even golfing.32 For those activities in which the potential for "getting lost" is high, and search and rescue services are often required as a result, GPS is much more than a useful gadget; it is a potentially life-saving device. 29 This system, known as Guidestar, is offered as an option in General Motor's Oldsmobile 88 model. It uses GPS as an accuracy monitor for a dead-reckoning and map-matching navigation system. 30 Source of information: Personal conversation with Michael Swiek, Executive Secretary of the U.S. GPS Industry Council. 31 The leaders of the two teams that have been awarded Phase II ITS contracts for continuation of architecture design are Rockwell International and Loral Federal Systems. It is too early in the design process to determine exactly what role GPS will play in either team's final architectures. Source of Information: personal conversation with Mr. Lee Simmons, National Architecture Team Leader for ITS, FHWA, 22 February 1995. 32 Several golf courses in the United States have experimented with DGPS systems mounted on golf carts to provide golfers with exact distances to the pin based on their location on the course.

GPS APPLICATIONS AND REQUIREMENTS 40 Table 2-6 Land Transportation Requirementsa Application Accuracy (2 Integrity Availability Coverage Resistance to drms) RF Inter- ference Time to Alarm Railroad Train Control 1.0 m 5s 99.7% Nation High ITS and Highway 5.020.0 m 1-15 s 99.7% Nation High Vehicle Navigation and Navigation/ Guidance Position- Alert Location Mayday/Incident 5.0-30.0 m 1-15 s 99.7% Nation High Fleet 25.0-1500 m 1-15 s 99.7% Nation High Management (AVL/AVI) Emergency 75.0-100.0 m 1-15 s 99.7% Nation High Response Automated Bus/ 5.0 -30.0 m 1-15 s 99.7% Nation High RailStop Annunciation Vehicle 30.0 -50.0 m 1-15 s 99.7% Nation Very High Command and Control Collision 1.0 m 1-15 s 99.7% Local Very High Avoidance, Control Collision 5.0 m 1-15 s 99.7% Local Very High Avoidance, Hazardous Situation Accident Data 30.0 m 1-15 s 99.7% Nation Moderate Collection Infrastructure 10.0 m 1-15 s 99.7% Nation Moderate Management Hazmat Vehicle or Cargo 5.0 m 1s 99.7% Nation High Locations Precision Automatic 0.05 m 5s 99.7% Local High Farming Vehicle Guidanceb Search & Location 10.0 m minutes 99.0% Nation High Rescue Determinationc Recreation Off-road 5.0 m minutes 99.0% Nation Moderate Vehicles, Hikers, Back-country Skiers, etc.c a.Integrity (1 minus PHE times PMD) and continuity of service requirements are not defined for land transportation applications. Source of other requirements, unless otherwise annotated: U.S. Department of Commerce, National Telecommunications and Information Administration, A Technical Report to the Secretary of Transportation on a National Approach to Augmented GPS Services, p. 9.

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The Global Positioning System (GPS) is a satellite-based navigation system that was originally designed for the U.S. military. However, the number of civilian GPS users now exceeds the military users, and many commercial markets have emerged. This book identifies technical improvements that would enhance military, civilian, and commercial use of the GPS. Several technical improvements are recommended that could be made to enhance the overall system performance.

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