LightSquared and GPS

FCC Request for Public Comments on LightSquared Petition for Declaratory Ruling
(Due Feb 27)

Reports and Public Comments Related to FCC Order of Jan 26, 2011

Illustration of Concerns with LightSquared Source: Chris Hegarty, MITRE
Mar 2, 2011

This page provides information about potential interference to GPS receivers from the LightSquared communications network. The main text below was updated July 7, 2011.

What is LightSquared?

LightSquared Subsidiary LLC is a company that plans to provide a wholesale, nationwide 4G-LTE wireless broadband network integrated with satellite coverage.

LightSquared will combine existing mobile satellite communications services (formerly known as SkyTerra) with a ground-based wireless communications network that uses the same L-band radio spectrum as the satellites.

On January 26, 2011, the Federal Communications Commission (FCC) issued an Order and Authorization giving LightSquared conditional approval to build out its ground-based wireless network (referred to as an ancillary terrestrial component, ATC) by reusing its authorized mobile satellite service (MSS) spectrum. The approval is subject to further testing and FCC review (see below).

Why is the GPS community concerned?

The base stations of the LightSquared network will transmit signals in a radio band immediately adjacent to the GPS frequencies. The GPS community is concerned because testing has shown that LightSquared's ground-based transmissions overpower the relatively weak GPS signal from space. Although LightSquared will operate in its own radio band, that band is so close to the GPS signals that most GPS devices pick up the stronger LightSquared signal and become overloaded or jammed.

There is also concern that the FCC may approve a technical solution to the problem that requires millions of existing GPS users to upgrade or replace their devices.

What is being done to address the concerns?

In its Order and Authorization, the FCC required that LightSquared create a working group with the GPS community "to address interference concerns regarding GPS and, further, that this [working group] process must be completed to the Commission’s satisfaction before LightSquared commences offering commercial service." LightSquared committed $20 million to the working group and worked closely with the U.S. GPS Industry Council and other participants to complete interference testing.

The FCC ordered LightSquared to file monthly progress reports and a final report due June 15, 2011. On June 15, LightSquared requested and the FCC approved an extension of the deadline to July 1, 2011. They submitted their final report on June 30, 2011, along with a separate document providing their recommendation to the FCC. The FCC opened a 30-day public comment period on the report and recommendations, with a comment deadline of July 30, 2011.

LightSquared cannot commence commercial operations of its terrestrial network until the FCC, "after consultation with NTIA [National Telecommunications and Information Administration], concludes that harmful interference concerns have been resolved and sends a letter to LightSquared stating that the process is complete."

Independent of the FCC-ordered study, the government's National Space-Based PNT Systems Engineering Forum (NPEF) conducted its own testing of the potential interference to military and civilian GPS users from LightSquared's terrestrial network. The NPEF completed its report on June 1, 2011; the unclassified public version was released July 6, 2011.

What is the Executive Branch position on this issue?

The government GPS community is working closely with LightSquared and the U.S. spectrum regulators to ensure that GPS users are protected from interference and unnecessary re-equipage. The U.S. Government continues to support the President's National Broadband Plan and facilitate its implementation consistent with the preservation of national and economic security.

Federal agencies have conducted extensive technical studies to understand the interference effects and seek potential mitigations. Their initial analysis is complete and was provided to the FCC through the National Telecommunications and Information Administration (NTIA). The results clearly demonstrate that implementing LightSquared's planned deployment for terrestrial operations poses a significant potential for harmful interference to GPS services.

Prior to the FCC Order and Authorization of January 2011, the National Coordination Office and multiple federal agencies expressed concern about potential GPS interference from LightSquared. On behalf of the Executive Branch, NTIA sent a letter to the FCC stating that the LightSquared proposal raised "significant interference concerns that warrant full evaluation" to ensure that federal agencies' use of GPS is not adversely impacted.

On July 6, 2011, the NTIA Administrator sent another letter to the FCC stating that, based on the government testing and analysis, his earlier concerns about GPS interference remain unresolved. He recommended that the FCC continue to withhold authorization for LightSquared to commence commercial operations. NTIA, in coordination with federal agencies, is still reviewing the LightSquared working group test results and will continue to consult with the FCC.

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