GPS Threatened with Widespread Interference

The Federal Communications Commission's (FCC) International Bureau recently granted a conditional waiver allowing the dramatic expansion of terrestrial use of the mobile satellite spectrum (MSS) immediately neighboring that of the Global Positioning System (GPS) - utilizing extremely high-powered ground-based transmissions that could potentially cause severe interference to hundreds of millions of GPS receivers.

The conditional waiver was granted to a company called LightSquared. The FCC's decision has caused serious concern within the GPS industry and user community. That's because LightSquared's planned use of the spectrum immediately adjacent to GPS is dramatically different from the limited "ancillary" ground-based use previously permitted by FCC rules - and, by every indication to date, is incompatible with existing GPS uses.

Initial technical analyses show that the distant, low-powered GPS signals would receive substantial interference from high-powered, close-proximity transmissions from LightSquared's planned network of 40,000 ground stations. The consequences of disruption to GPS signals are far reaching: LightSquared's facilities could create tens of thousands "dead spots" - each miles in diameter - throughout U.S. cities where there was a LightSquared transmitter.

Therefore, it is imperative that the LightSquared system not be deployed unless it can be conclusively guaranteed that the GPS system - a national utility on which millions of Americans depend every day - is fully protected from radio interference. The problem LightSquared's plans pose and additional steps the FCC needs to take are explained below.

The usual FCC process is to conduct extensive testing followed by approvals. For LightSquared, the process was to approve first, then test. The unusual fast-track procedure also did not allow Commissioners the opportunity to vote on the matter. The waiver recently granted to LightSquared through these unorthodox procedures allows it to use its satellite spectrum for high-powered ground-based broadband transmissions if the company can demonstrate that harmful interference could be avoided.

• Issues of interference should have been addressed before the waiver was granted.
• The waiver was granted in just two months. Even with such a short window, the U.S. GPS Industry Council, the National Telecommunications and Information Administration (NTIA) - along with some federal departments, state and local governments, public safety authorities, and GPS commercial users - all voiced strong objection to LightSquared's plans.
• The problem arose because LightSquared, which is backed by a New York hedge fund, bought the spectrum right next door to GPS cheaply, hoping to change the rules and make the spectrum more valuable. The FCC's process has been driven by this private, speculative decision, rather than sound spectrum planning.
• Under FCC rules in place prior to the January, 2011 waiver the FCC only permitted "ancillary" terrestrial uses which supported a primary mobile satellite service. These ancillary operations were intended to "fill in" locations where satellite coverage was problematic. In its January order, the FCC green-lighted a high powered nationwide terrestrial broadband network in spectrum reserved for satellite services, turning rules permitting "ancillary" use on their head.

LightSquared plans to transmit radio signals that would be one billion or more times more powerful than the signals that GPS receives- potentially causing severe interference impacting hundreds of millions of GPS users. This includes receivers used by U.S. federal agencies, state and local governments, first responders, airlines, industry, civil engineering, construction and surveying, agriculture, and everyday consumers in their cars and on hand-held devices.

• Results of initial technical analyses show that GPS signals, which are low-powered and originate from distant satellites, would receive substantial interference from LightSquared's network of high-powered, close-proximity ground station transmissions.
• GPS satellites are solar powered and send signals using 50 or fewer watts, about what it takes to power a refrigerator light bulb. That signal then travels 12,000 miles, and the resulting amount of power received on Earth by a GPS receiver is extremely faint.
• Contrast that to LightSquared's planned ground transmissions powered with 1,500 watts of power transmitting as short a distance as a few hundred feet. This leads to a situation where the low powered, distant GPS signals would be "drowned out" by the nearby, high-powered transmissions in the immediately neighboring frequency band.
• LightSquared's planned use of these high-powered terrestrial networks in the frequency immediately adjacent to the GPS frequency is unproven and unprecedented and is almost certain to be found to be fundamentally incompatible with existing GPS uses when detailed studies are complete.

The Global Positioning System was first launched more than 30 years ago and is now a critical and extremely reliable part of our national infrastructure. Millions use it routinely every day.

• The Federal government has invested $35 billion in the GPS satellite constellation alone, and many more billions in critical systems that use GPS. Industry and users have also spent billions on GPS based technologies and devices.
• The US is the world's leader in GPS technology, and our GPS infrastructure is the envy of the world. Russia, China, and the European Union are all building competitive systems that could supersede a hobbled US system.
• Government agencies and businesses that use or make GPS based systems and devices employ millions of people.

Significant interference with GPS would endanger the use of GPS in many critically important sectors, including:

• Homeland Security: GPS equipment is widely used by the Departments of Defense, Interior, Transportation, Commerce and Homeland Security. Federal, state, and local government employees rely on GPS equipment in disaster response, public safety, and security and management of national assets and infrastructure.
• Public Safety: First responders such as law enforcement, fire fighters, and emergency medical personnel rely on GPS day-in and day-out to provide critical instant location and route information.
• Consumers: Millions of Americans use GPS-enabled consumer devices in their cars and on their cell phones and other hand-held devices as vital, reliable every day navigational tools.
• Aviation: More than 150,000 aircraft use GPS receivers. GPS and the Wide Area Augmentation System - which would also be affected -- have long been approved by the Federal Aviation Administration for aircraft navigation and GPS instrument approaches now provide a landing system option at the many U.S. airports which lack land-based instrument landing systems. GPS also plays a critical role in the FAA Next Generation Air Transportation System, designed to modernize air traffic control and meet expanded air traffic capacity.
• Marine: GPS is used for navigating the open seas as well as congested harbors, ports and waterways by commercial vessels, search and rescue operations and recreational boating. It is also used for commercial fishing, underwater surveying, dredging, marine construction, buoy placement, navigational hazard location and mapping as well as automated container placement and management in some of the world's largest ports.
• Transportation: GPS equipment is used in critical asset management activities for road and rail infrastructure - improving efficiency, lowering costs and enabling better decision making. The Federal Rail Administration's Positive Train Control mandate further drives the use of GPS to prevent train-to-train collisions, derailments, and casualties or injuries to railway workers. GPS is used to help fleets lower fuel consumption and decrease their carbon footprint.
• Agriculture: Farmers use GPS to in precision agriculture to improve planting efficiency and increase crop yields, more efficiently use scarce water and fuel, and comply with U.S. Department of Agriculture reporting regulations. GPS allows for the precise application of pesticides and fertilizer, reducing environmental impacts, and is used in nearly 95 percent of all crop dusting.
• Forestry: The U.S. Forestry industry and Forest Service use GPS in forest land management and for Forest Automation Systems that improve logging efficiency and reduce environmental harm.
• Engineering and Construction: The U.S. building, construction, and civil engineering industry - one of the economic sectors most severely impacted by the recent recession - has made large investments in the use of GPS technology to modernize and automate construction sites, machines and processes. GPS is also used to monitor the movement of bridges, dams, mines, and other natural and manmade structures.
• Surveying, Mapping, and Land Management: GPS is an essential part of the national geodetic infrastructure and is used in surveying and mapping activities necessary for land title transactions, land development, civil engineering and accident investigations as well as the field creation, maintenance and use of geographic information systems (GIS) databases that underpin our national digital mapping infrastructure.
• Utilities: GPS signals aid utility services such as electrical power, water, gas and telecommunications in multiple ways. This includes synchronizing utility networks and the power grid, maintaining and managing infrastructure and coordinating rapid responses to network outages and incidents.
• Natural Resources: Natural resources industries engaged in the exploration, production and distribution of energy and minerals rely on the GPS service throughout their operations.
• Disaster Management and Scientific Research: High-accuracy GPS networks are deployed along crustal faults and around volcanoes. The resulting data is used to study and better understand crustal movements that cause earthquakes and volcanic eruptions. In addition to disaster prevention and relief, GPS is also used for weather services and scientific research.

Any claims of technical fixes for the interference problem are unproven and highly suspect. There is no known technical fix for this problem, and the laws of physics suggest that there won't be any viable fix. This is not a problem with GPS receivers - it comes from allowing unrestricted high powered terrestrial stations in spectrum immediately adjacent to the band used by GPS.

• LightSquared's plan to operate a nationwide high-powered terrestrial network in satellite frequencies immediately adjacent to the GPS frequency band is completely unprecedented. Any technical arguments regarding the ability of the two systems to co-exist are theoretical and unproven.
• This is not a "problem" with GPS receivers. GPS receivers already use state-of-the art filters. GPS receivers are designed to be highly sensitive in order to detect very distant and very low-powered GPS satellite transmissions. GPS signals are so faint and LightSquared's ground station signals are so powerful that no existing GPS filter can overcome this physics problem.
• Even if filters become available at some point in the future, there is no possible way to "retrofit" hundreds of millions of GPS receivers already in use.
• While GPS operators understood and agreed that satellite operators in the MSS band could deploy terrestrial service on an ancillary basis, to complement satellite-based services in areas where satellite reception was weak, there was never any agreement to the kind of dense terrestrial network that LightSquared now proposes for the MSS band.

The GPS industry is committed to work with LightSquared, FCC, NTIA and other interested parties in the FCC's working group process.

• In recognition of the potential interference to GPS receivers, the FCC, as part of its January 26, 2011 modification order, required the establishment of a working group to bring together LightSquared and the GPS community. This working group will study interference concerns, identify measures to prevent interference and produce a report for FCC review no later than June 15, 2011.

However, we believe that additional safeguards are needed. We recommend:

1. The FCC must make clear, and the NTIA must ensure, that LightSquared's license modification is contingent on the outcome of the mandated study unequivocally demonstrating that there is no interference to GPS. The studies must be comprehensive, objective, and based on correct assumptions about existing GPS uses rather than theoretical possibilities. Given the substantial pre-existing investment in GPS systems and infrastructure, and the critical nature of GPS applications, the results of studies must conclusively demonstrate that there is no risk of interference. If there is conflicting evidence, doubts must be resolved against the LightSquared terrestrial system. The views of LightSquared, as an interested party, are entitled to no special weight in this process.
2. The FCC should make clear that LightSquared and its investors are proceeding at their own risk in advance of the FCC's assessment of the working group's analysis. While this is the FCC's established policy, the Commission's International Bureau failed to make this explicit in its order.
3. As the FCC has already said, resolution of interference has to be the obligation of LightSquared, not the extensive GPS user community of millions of citizens. LightSquared must bear the costs of preventing interference created by their network and devices, and if there is no way to prevent interference, it should not be permitted to operate. GPS users or providers should not have to bear any of the consequences of LightSquared's actions.
4. This is a matter of critical national interest. There must be a reasonable opportunity for public comment of at least 45 days on the report produced by the working group and further FCC actions on the LightSquared modification order should take place with the approval of a majority of the commissioners, not at the bureau level.