Global Navigation Satellite Systems
From Blindside
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[edit] What is it
"Global Navigation Satellite System" is the generic term for systems that, like the popular and well-known Global Positioning System (GPS), enable users on the earth's surface to precisely determine their location.
The Global Positioning System (GPS) is currently the only fully functional Global Navigation Satellite System (GNSS), although several other such systems exist or are in the process of being built. All but one of these are military in origin. Russia began development of GLONASS in 1976, but the system fell into disrepair during the 1990s. It is now being renovated in a partnership with the Indian government and the goal is to cover the globe by 2009. China is considering expanding its Beidou navigation system to cover the globe. Finally, Europe is in the testing phase of Galileo, which is intended to be fully deployed by 2012 at an estimated cost of €3 billion.
Update Sept. 2007: The Galileo system, envisioned as a preliminary launch of four publicly funded satellites to be followed by the remaining 22 financed by a consortium of private companies, has run into funding difficulties. Needing 2.4 billion Euros to finance project continuation between 2007 and 2013, the EU is evaluating (at least) two funding alternatives.
Galileo is the only civilian GNSS; as GPS has become increasingly important around the world Europe has become less willing to depend on a system funded by the US military that, even if only theoretically, could be turned off or degraded at any time. Receiver manufacturers are expected to take advantage of the increase in available navigation satellites by making receivers that work with both GPS and Galileo, increasing navigational accuracy and ensuring there are fewer "holes" in coverage. Urban areas are a particular problem, as tall buildings tend to block the satellites' signals from reaching street level.
GPS was a significant scientific achievement for another reason: in creating the system, lead investigator and inventor Robert L. Easton experimentally verified Einstein's Theory of Relativity.
Developed by the United States Department of Defense, GPS is made up of 24 satellites, which are managed by the United States Air Force 50th Space Wing at an annual estimated cost of US$750 million. That sum includes replacing aging satellites as well as research and development. GPS is free for civilian use as a public good.
All GNSS work the same way. Each member of a constellation of satellites continually broadcasts the precise time and its exact location. A receiver on the earth's surface compares the length of time it takes for four (ideally) satellite signals to reach it and uses the differences to calculate location, direction, and speed, When complete, Galileo will be made up of 30 satellites. The current version of GPS has 24 medium Earth orbit satellites; these are due to be updated by 2014. GPS has become a widely used aid to navigation worldwide, and a useful tool for mapping, land surveying, commerce, and scientific research into the atmosphere and ocean roughness. GPS also provides a precise time reference used in many applications including synchronising telecommunications networks and studying earthquakes.
[edit] Impact & Maturity assessment
Impact: 3 and Maturity: 3
[edit] Information Assurance issues
GPS has grown to drive a billion-dollar market. It is valuable in a variety of applications from air traffic control to simply enabling consumers to find their way in a strange town. However, privacy advocates are concerned by the potential for third parties to use GPS to track individuals, arguing that privacy is being sacrificed for a marginal increase in safety.
GPS systems are vulnerable to external threat. Given the increasing number of functions loaded onto the back of GPS, it may be somewhat of a surprise just how vulnerable. China made that eminently clear by exploding a rocket in low orbit earlier this year, generating debris that would disable a satellite if it flew through it. Quite a few countries could replicate the feat. Even without fireworks, GPS systems can be jammed--and China recently bought a jamming system from the Ukraine, according to a U.S. Defence Department report in June. GPS systems are also vulnerable to solar flares and unintentional jamming from television stations. There have been two satellite failures, in 1995 and 1997. And, of course, there is always the threat that a provider of GPS services could just turn it off.
Perhaps one of the greatest issues is the ability of the system owner (the U.S., and primarily the U.S. Department of Defense) to degrade performance intentionally should the state of international relations make that desirable. Note: The U.S. DoD has recently announced (September 19) that the next generation of satellites will no longer have that capability.
The General Lighthouse Authorities (GLA) of the United Kingdom and Ireland – which operate aids to navigation systems and lighthouses – announced May 31 that they awarded a 15-year contract to develop a state of the art e-Loran system to serve the two countries as a backup to GPS systems, and the US department of Homeland Security has issued a call for comments on doing the same. (The U.S. has been steadily increasing eLoran infrastructure spending, to a total of $120 million in 2004.) However, eLoran systems would not provide much backup to commercial location-based services providing fleet information or other GPS services.
The arrival of Galileo and revival of Glonass, EU and Russian satellite systems respectively, introduces interoperability, timing and synchronization issues for information exchange between diverse satellite systems. Broadcasting each system's mutual time offset was agreed as the way forward in 2005, as was done with GPS and the previous iteration of Glonass. A recent work group said this has so far posed challenges in meeting agreed standards for the U.S. GPS and Galileo, although solutions will be tested in 2008. A workgroup for interoperability between GPS and Glonass was to have convened in April 2007, but no findings have been published from that session.
Glonass, the partial network put up by the Soviet Union, is scheduled to be revived and completed in partnership with India. India has recently announced its intention to create a mini-constellation of 7 satellites to provide India-specific coverage. It is not clear at this time if those satellites are intended as part of India's contribution to Glonass.
There are also data protection and privcacy issues regarding GPS services. Using GPS to track cell phones is popular, particularly with parents in the name of child safety. But it is not hard to imagine ways in which cell phone tracking could invade privacy. Besides the obvious uses for domestic spying, such data could be demanded by police (as similar data collected by the EZ-Pass RFID toll collection system has been). In February 2007 an appeal based on the Fourth Amendment's right to privacy was denied in the case United States v. Garcia, in which, without a warrant, police planted a GPS memory tracking device to accumulate evidence against a man suspected of methamphetamine manufacture.
For example, GPS is popular with suspicious or worried employers, parents, and spouses, who can attach a £300 GPS system to the underside of a car with magnets and use it to monitor its use. The technology allows them to remotely download data, including the car's location and speed, from the receiver onto their computer. Some devices automatically email or call parents when their child is speeding or has entered a location previously designated as off-limits. The most sophisticated versions allow parents can remotely sound an alarm, honk the horn or flash a light when their teen is driving too fast. In the US, the appliance manufacturer Whirlpool has claimed using such a system enabled it to cut the service miles clocked up by its 440 technicians across the US by 10 percent overall – and up to 30 percent in some cases.
Car rental companies have installed GPS devices in their fleets since the mid-1990s to give drivers directions while they're on the road. More recently, they have begun using the data to track the locations of their vehicles. US-based "fleet management" companies such as AirIQ and Fleetrack also sell newer tracking services that help companies monitor their vehicles and even disable them remotely. The end-user companies may insist that such policies are solely intended to protect their fleet, but some customers and employees disagree on privacy grounds. In 2001, a Connecticut driver sued a car rental company after it fined him because GPS tracking showed he'd broken the speed limit three times, calling the technology "intrusive".
GPS is also commonly used by emergency services to locate people in need of help. In the US, since 2005, this is handled by a system called E911 ( for "enhanced 911", after the emergency telephone number). Newer mobile phones include the ability to let emergency operators calculate a caller's location, either by using GPS or by triangulating from the strength of the phone's signal when it reaches the nearest mobile phone masts.
[edit] Implications for UK Government
There are numerous potential threats to services provided by satellite networks. Hence, large government systems based on such services are to some extent vulnerable.
Many of these services will be military in nature or concerned with law enforcement. However systems for civilian maritime and aviation navigation would also be affected.
Another system vulnerable to disruption is ANPR (Automated Number Plate Recognition). There are two realistic threats to this system (realistic in the sense that they do not presuppose a war or catastrophe). The first is integrity--can the informatio survive court challenge. The second is guarantee of coverage, which may end up being wholly dependent on a high degree of interoperability and co-operation between the US Department of Defence, the Russian/Indian Glonass system, and the EU. Should international relations worsen, a decision to withhold service could threaten the viability of ANPR.
As currently constituted, this would not threaten life or public safety. However, it is natural to assume that more services will be loaded onto both the general satellite services and the infrastructure of ANPR. UK government decision makers will need to have a plan B for delivery, either by retaining legacy delivery systems or encouraging the develoopment of backup systems and workarounds.
Perhaps even more serious is the possibility that the information provided by the various satellite systems can be corrupted by external hackers. This does have the potential to threaten lives and public safety, and government services should be aware that this possibility exists and take appropriate security measures when dealing with contractors.
[edit] Timescale
GPS usage continues to grow. According to a report from the Electronics Industry Market Research and Knowledge Network, the market could expand to $28.9 billion by 2010, with further growth to come as Galileo, GLONASS, and Beidou come onstream. Therefore, its impact is likely to be seen in the short and medium term, over the next 25 years.
[edit] Examples
GPS satellite receivers as new tool for earthquake studies
GPS in telemedicine.
EU's Galileo will interoperate with GPS
GPS used to study ocean roughness (PDF)
New $5.2 million MBTA (Massachusetts Bay Transit Authority) system using GPS equipment to pinpoint train locations and times
GPS in use to <a href="http://www.t-g.com/story/1223064.html">locate emergency callers</a>
Police allowed to GPS to track drivers
British government proposes to use GPS to implement road use pricing
GPS used to track spouses – in the name of safety
GPS used in employee surveillance
[edit] Comments (attributed)
“In Latin America, the ability to track people is becoming attractive. Personal security is a big issue there." -- Steve Brown, vice president for Qualcomm's Internet services division.
“GPS could become a feature in almost every aspect of life in the future. Autonomous vehicles, airplanes and ships could soon be navigating without a human pilot. Individuals, including blind people could have GPSs implanted and never lose their sense of direction.” -- Philip Dunn
[edit] Organisations
Global Positioning Systems Wing
BIGF (the British Isles GPS archive Facility)
[edit] Documents & research papers
GPS Basics: Introduction to the system (PDF)
Integrating the GPS with LPS – The three dimensional orientation problem (PDF)
GPS and GIS for hurricane debris removal (PDF)
GPS and The Internet: A combination with privacy risks
[edit] Experts (academic, practitioner)
Dr. Robert A Nelson, president of Washington, DC-based Satellite Engineering Research Corporation and author of Satellite Communication Systems Engineering.
Stephen B Heppe, Vice President of Avionics for Bingen, Washington-based Insitu Group and a consultant and expert witness in satellite communications, GPS, Voice over IP, and aircraft-related technologies.
Martin Unwin, head of the GSNN/GPS team at Surrey Satellite Technology, Limited, Guildford, Surrey, UK. SSTL designs and manufactures small, low-cost satellites.
