Forum on NOAA's National Spatial Reference System (1994)

Participants at the forum agreed with the concept of the NSRS but had some concerns about the apparent priorities and details of its implementation as stated in the Strategic Goals and Implementation Plan. Despite the wide array of disciplines represented at the forum, participants shared the following thoughts about NOAA's plans for a NSRS. More specific concerns, defined by the forum working groups, are detailed in the chapter that follows.

The NSRS has the potential to provide enormous economic opportunities and societal benefits to the country. The potential benefits of the NSRS include the following:

• economic gains from nontraditional uses of the system (e.g., precision agriculture, Intelligent Vehicle Highway Systems (IVHS), reducing the size of flight corridors and the space between aircraft, near-automatic aircraft landings, timely shipping and routing of freight without warehouse storage) in the United States and foreign markets,

• better support of the surveying and mapping communities,

• key role in the National Spatial Data Infrastructure (NSDI), which is a priority of the current administration. The importance of a highly accurate geodetic control network in the NSDI is described in the 1993 NRC report, Toward a Coordinated Spatial Data Infrastructure for the Nation. Geodetic control is required to systematically register all spatial information to allow their integration into Geographic Information Systems (GIS). Such GIS systems have application in wetlands delineation, mineral assessment, renewable resource management, public health, urban and regional planning, disaster response and recovery, and national defense, among others.

Although many of these benefits could be realized without the NSRS, participants at the forum felt that the implementation of a single, coordinated reference system would yield the maximum returns. To provide the necessary framework for these activities, however, NOAA must coordinate with the private-and public-sectors that will be responsible for many aspects of implementation (e.g., Coast Guard and FAA [Federal Aviation Administration] are establishing CORS with NOAA's guidance). Moreover, if kept involved, these communities

could provide the funding necessary to augment and accelerate the program. Forum participants felt that NOAA's proposed budget initiative of about $8.4M/year for 5 years was unrealistically low to carry out the intended plan using existing technology and capabilities, particularly if a significant number of CORS are installed. NOAA and its partners should set priorities to ensure that the most important aspects of the program are implemented.

Recommendation 1. NOAA should coordinate with its public- and private-sector partners in implementing the NSRS, including setting a realistic budget and program milestones.

The proposed NSRS could satisfy a basic framework need for a broad user community that includes transportation, emergency response, utilities, industry, and research, as well as surveying. Many of these communities, however, are unaware of the existing geodetic network and how it would benefit them, or of the new GPS capabilities that NOAA will provide in the NSRS. Consequently, they often create their own local networks, using references other than geodetic control, which cannot be connected easily with other local networks. By promoting use of a seamless GPS-based network, NOAA could discourage the creation of incompatible positioning systems, increase business efficiency, and lower costs. Participants estimated that literally billions of dollars could be realized from savings and/or new applications that depend on accurate positioning, both at home and abroad. Moreover, by involving stakeholders in the private- and public-sectors in the design and implementation of the NSRS, NOAA will help to ensure that the positioning needs of the broadest user community will be met.

Recommendation 2. NOAA should encourage the non-traditional user communities to participate in the development and use of the NSRS.

To realize its full economic potential, the NSRS must be made functional as soon as possible. Delays will force those organizations that have an interest in using GPS to develop their own specialized positioning systems. NOAA should move quickly to ensure that the aviation and IVHS communities, for example, have real-time access to an accurate, reliable reference system. They will need radiobeacon signals from a NSRS-CORS point in real-time, similar to those the Coast Guard is installing along the nation's shorelines. Indeed, transportation developments, which are occurring rapidly in the private sector, will be a major driver of the system.

Recommendation 3. To keep pace with developments in the public-and private-sectors, the NSRS must be functional within 5 years.

The evolution from monumented stations to a large array of CORS was viewed by most forum participants as inevitable. Rather than concentrate on installing the federal, cooperative, and user densification networks, NOAA should install as many CORS as is feasible, at existing geodetic control stations where possible. As the demands for near real-time data increase, universities, industry, and federal, state, and local government agencies will install additional CORS where needed to meet their specialized needs. NOAA need not be responsible for installing and maintaining 1300-1500 CORS, which is the estimated minimum useful number of stations for nationwide needs, but it should provide oversight and incorporate some of the stations installed by other interests into the NSRS.

Recommendation 4. NOAA should concentrate its efforts and resources on the implementation of CORS, whether installed by NOAA or by other agencies and organizations. The Implementation Plan should better reflect the evolutionary nature of the network.

NOAA has an important role in assisting universities, the private sector, and government agencies to furnish GPS data that strengthens the NSRS, and in providing standards and specifications for network stations. NOAA has traditionally provided standards for the observation, monumentation, and placement of physical monuments, although these have not always been made available in a timely fashion. With the development of CORS, however, NOAA should also develop standards for collecting and disseminating near real-time data. These standards must be adopted immediately so that both the government and university/industry/public/private portions of the network can be integrated to form a truly national framework.

Recommendation 5. NOAA should place a high priority on developing standards, particularly for CORS, and making them available to the public.

In addition to making standards available, NOAA should strive to make all its data and information relating to the NSRS of high quality and easily accessible. Potential users must not encounter needless difficulties in obtaining data and must have software that is "user friendly" and compatible with the most commonly used computers. At the same time, there should be uncomplicated mechanisms for users to submit their data to NOAA, or point out inconsistencies in published NOAA data.

Recommendation 6. NOAA should facilitate easy two-way communication with their users to facilitate data dissemination and further refinement of the accuracy of NOAA data.

The State Geodetic Advisors have an important role in the NSRS. As the established link to NOAA expertise, procedures, and standards, they have historically assisted local governments and surveyors in the proper use of geodetic control in mapping and surveying. To be equally effective in the GPS era, however, they need to be well trained in the use of modern positioning techniques. NOAA should ensure that its State Geodetic Advisors are fully trained in GPS methods and should increase the number of advisors so that each state can take advantage of this resource. Because the State Geodetic Advisors facilitate the use of the NSRS, the costs of expanding the program should be included in the NSRS budget.

Recommendation 7. NOAA should provide a well trained State Geodetic Advisor to each state or region.

The steering committee recognizes that the success of the NSRS depends on GPS remaining available for civilian use. Many forum participants expressed concern that users would rely on a GPS-based reference system, only to have the Department of Defense (DOD) restrict its use. Others felt that expanding use of GPS by civilians would be the best assurance of its continuation. DOD currently limits the utility of GPS through its implementation of Selective Availability (SA) and Anti-Spoofing (AS). Without SA, dual-frequency GPS pseudo-range measurements can provide 1-10 m accuracy. With single-frequency pseudo-range measurements, 10-20 m positioning is possible. With SA activated, these accuracies can only be obtained through differential systems that the users must install. The effects of SA on dual-frequency carrier phase differential position determinations are approximately = 1 mm for all applications. With AS active, the large loss of signal strength at the L2 frequency degrades dynamic applications or applications that require rapid static measurements except in the latest generation of receivers. Consequently, the implementation of AS makes GPS measurements and surveys less robust and more expensive.

Recommendation 8. NOAA should participate actively in the debate on the utility of SA/AS with specific note of the costs to the civilian sector.

Despite these uncertainties, the steering committee and forum participants were pleased to have had the opportunity to provide input on NOAA 's plans for a NSRS. The NSRS represents a major step forward in the challenging task of meeting the spatial data needs of the nation, and the steering committee looks forward to its first successes.