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Adding Josh to American Beauty: GPS Re-incarnated

The recent decision to remove selective availability for GPS signals may double the GPS market in every two to three years.

Bill Clinton will become history in a few months time, but the GPS community would not forget this idol for a long time to come. By passing the orders for removal of Selective Availability (S/A) for the GPS signals, he has removed the biggest bottleneck for the technical advances which can be made using GPS. This decision to remove S/A was in pipeline since 1996, when Clinton had announced that S/A would be discontinued from 2006. But what came, as a pleasant surprise, was the announcement by White House on 1st May, 2000 to discontinue S/A on Navstar GPS satellites.

Selective Availability: How did the ice break?
S/A was designed to purposely degrade the quality of the civilian GPS signals. The main idea for the implementation of S/A was the fact that the signals could be easily used by the enemy sates against US.

However, such restrictions cannot be justified in today’s techo-savvy world as these handicaps can easily be removed by using a Differential GPS (DGPS) system, which although costly enough for normal civilian use, is cheap enough for an enemy state to plan some drastic measures. However, the common user has to feel the brunt of such restrictions as he receives degraded information, which in turn, affects the growth of the GPS related applications and because of that the ‘GPS market’ can also feel the pinch of such ‘restrictions’.

Another possible reason for the decision is perhaps the fear of losing the monopoly which US enjoys by providing GPS services. GLONASS, Russia’s answer to NAVSTAR is in a mess. With Russian economy in doldrums, any improvement in the quality of its services would remain a dream. US never heeded the Europeans’ desire to share GPS management responsibilities as well as built some GPS satellites. The result of this behaviour was Europe’s decision to pursue its own Global Navigation Satellite System (GNSS-2) christened as ‘Galileo’. What US fears from Galileo is not the benefits one gets from increased number of satellites, but Europeans’ interest in business implications of satellite navigation. European countries are more interested in generating resources and revenues by creating a navigation system based on different standards. For this, it will become mandatory for everyone within Europe, to use that system and incorporate them into all their goods. In order to avoid the inconvenience of reconfiguring the products in different markets, worldwide acceptance of such mandated components would be on a rise. In other words, Galileo will start eating into the US playground. Moreover, the “basic public service” signal , equivalent to GPS, which would be provided by Galileo, is expected to give an accuracy of about 10 metres.

These facts must have motivated US to plan a strategy for remaining ahed in the race. Removal of S/A is perhaps the first step in this direction. Whatever be the reason, the entire community will benefit from this decision. The decision has tactfully solved the security concerns to provide precise capability to enemy states. US with a large amount of GPS guided precision ammunitions certainly cannot allow its enemy to benefit from the same capabilities. Thus US has reserved the right to deny the enemy state the same capability as and when it wishes or in other words a “selective denial” of the same signals. Shunning aside the negative uses of fully accurate GPS signals one can see an entirely new world of vehicle navigation, high precision consumer hand-held receivers and wireless communications to name a few benefits.

Market Trends
Users of GPS will now find themselves flooded with position information which is about 10 times more accurate than earlier. This will encourage the acceptance of the integration of GPS for peaceful purposes, encouraging and promoting safety and efficiencies in transportation and other fields. The market for GPS applications and services is in the multibillion range and with the recent decision the market is bound to double every two to three years time. The future will present a scenario in which a single receiver positioning and navigation system will provide cheaper, better and faster technology.

GPS companies all over the world are celebrating the decision as it would enhance their products capabilities. The President and CEO of Magellan Corporation stated, “Our products have become more valuable and useful overnight. The same GPS receiver that provided accuracy within 100 metres of a user’s location yesterday, is providing position fixes with as good as 10 metres accuracy today. This change immediately makes GPS more accurate and reliable, and thus more valuable to our GPS customers.” Trimble also rejoiced on this occasion and Steven W. Berglund, President and CEO of Trimble said, “The decision to turn off S/A is a milestone in GPS history and it underscores the importance of the technology as a global information utility. Today, users of Trimble GPS for public safety, asset and fleet management, the GPS community would not forget this idol for a long time to come. By passing the orders for removal of Selective Availability (S/A) for the GPS signals, he has removed the biggest bottleneck for the technical advances which can be made using GPS. This decision to remove S/A was in pipeline since 1996, when Clinton had announced that S/A would be discontinued from 2006. But what came, as a pleasant surprise, was the announcement by White House on 1st May, 2000 to discontinue S/A on Navstar GPS satellites.

Cashing from the change
The companies surely have a reason to rejoice as it would improve their quality of products. But the users would gain the most from this kind of a decision. Normal users utilising simple hand-held GPS for their boats, for riding their mowers, farmers using GPS to map and tailor applications of seeds and chemicals, oil companies using GPS to identify drill sites etc. will find that the results are 10 times more accurate as before. This means greater efficiency in work and higher productivity. Another application which would make most out of this decision are the navigation management systems. With the help of the removal of S/A, it would be possible to pinpoint the exact lane in which a car is travelling. The location of the car and lanes on which it is travelling would be far more accurate than ever before. Thus lanes, by-lanes, main roads could all be differentiated easily.

Also removal of S/A would provide super-reliable atomic clocks making GPS timing more accurate. With the help of this highly reliable velocity estimates can be easily made. Thus we find that apart from super-reliable GPS timing, the position and velocity accuracy will also increase. A major impact of increased accuracy of GPS timing is its use in the telecommunication industry. Many telecom operators use GPS to support synchronisation solutions that improve the quality of the wireline and wireless networks. With the removal of S/A, the telecom operators would be able to pinpoint the accuracy of time data broadcast by GPS to within 40 billionths of a second, thus providing high quality of service. Providing his view points, Thomas W. Steipp, President and CEO of Symmetricom stated, “More accurate timing is particularly crucial as wireless and wireline operators begin to deploy systems that support higher speeds of data transfer, as these systems require more precise timing to ensure high Quality of Services (QoS).”

Road Ahead
However, the recent trend certainly does not mean an end to differential GPS. Differential GPS will still be required for applications requiring very high accuracy. Aviation industries, surveying, mapping and high precision agricultural machine-control industries would still require the services of differential GPS.

The removal of S/A is just one step forward for the availability of accurate information. Another security feature, which is yet to be removed, is the Anti-Spoofing (A-S). Ionospheric delays can completely removed if dual frequency receivers are used. For normal civilian use, only the C/A code signal transmitted on one frequency can be utilised. The P-code signal, which is transmitted on both the frequencies, is encrypted under the Anti-Spoofing security feature. Only military receivers and advanced geodetic receivers can utilise both the frequencies. Thus the normal civilian user is deprived of the system for removal of ionospheric delays.

The decision to remove S/A is a clear indication that the US Government is trying provide the best global position, navigation and timing on the planet. But this is certainly not the last step as there are still several hurdles to conquer.

Statement by the President regarding the United States’ decision to stop degrading Global Positioning System accuracy. May 1, 2000

Today, I am pleased to announce that the United States will stop the intentional degradation of the Global Positioning System (GPS) signals available to the public beginning at midnight tonight. We call this degradation feature Selective Availability (SA). This will mean that civilian users of GPS will be able to pinpoint locations up to ten times more accurately than they do now. GPS is a dual-use, satellite-based system that provides accurate location and timing data to users worldwide. My March 1996 Presidential Decision Directive included in the goals for GPS to: “encourage acceptance and integration of GPS into peaceful civil, commercial and scientific applications worldwide; and to encourage private sector investment in and use of U.S. GPS technologies and services.” To meet these goals, I committed the U.S. to discontinuing the use of SA by 2006 with an annual assessment of its continued use beginning this year. The decision to discontinue SA is the latest measure in an on-going effort to make GPS more responsive to civil and commercial users worldwide. Last year, Vice President Gore announced our plans to modernize GPS by adding two new civilian signals to enhance the civil and commercial service. This initiative is on-track and the budget further advances modernization by incorporating some of the new features on up to 18 additional satellites that are already awaiting launch or are in production. We will continue to provide all of these capabilities to worldwide users free of charge. My decision to discontinue SA was based upon a recommendation by the Secretary of Defense in coordination with the Departments of State, Transportation, Commerce, the Director of Central Intelligence, and other Executive Branch Departments and Agencies. They realized that worldwide transportation safety, scientific, and commercial interests could best be served by discontinuation of SA. Along with our commitment to enhance GPS for peaceful applications, my administration is committed to preserving fully the military utility of GPS. The decision to discontinue SA is coupled with our continuing efforts to upgrade the military utility of our systems that use GPS, and is supported by threat assessments which conclude that setting SA to zero at this time would have minimal impact on national security. Additionally, we have demonstrated the capability to selectively deny GPS signals on a regional basis when our national security is threatened. This regional approach to denying navigation services is consistent with the 1996 plan to discontinue the degradation of civil and commercial GPS service globally through the SA technique. Originally developed by the Department of Defense as a military system, GPS has become a global utility. It benefits users around the world in many different applications, including air, road, marine, and rail navigation, telecommunications, emergency response, oil exploration, mining, and many more. Civilian users will realise a dramatic improvement in GPS accuracy with the discontinuation of S/A. For example, emergency teams responding to a cry for help can now determine what side of the highway they must respond to, thereby saving precious minutes. This increase in accuracy will allow new GPS applications to emerge and continue to enhance the lives of people around the world.