This page has permanently moved from PNT.gov to GPS.gov. Please update your bookmarks and links.

LightSquared and GPS

Updated August 22, 2012

Latest Developments

The due date for reply comments was March 30, 2012. Click to access the test reports, government letters, FCC announcement, FCC public notice, and more.

This page provides information about potential interference to GPS users from the LightSquared communications network.

What is LightSquared?

LightSquared Subsidiary LLC is a company seeking FCC approval to provide a wholesale, nationwide, wireless broadband network integrated with satellite coverage.

LightSquared intends to combine its existing satellite communications services with a ground-based 4G-LTE network that transmits on the same radio band as its satellites. The band is right next to the primary GPS frequency (L1).

Why is the GPS community concerned?

Illustration of Concerns with LightSquared
Source: Chris Hegarty, MITRE

The GPS community is concerned because testing has shown LightSquared's ground-based transmissions overpower the relatively weak GPS L1 signals from space.

Although LightSquared would operate in its own authorized band, the band is so close to the GPS signals that many GPS devices could pick up the stronger LightSquared signals and become overloaded or saturated.

There is also concern that millions of existing GPS users could be forced to upgrade their devices and/or accept GPS performance losses to accommodate the new network.

What is the current status of the LightSquared network?

In January 2011, the Federal Communications Commission (FCC) gave conditional approval for LightSquared to build out its ground network (referred to as an ancillary terrestrial component, ATC) by reusing its mobile satellite service (MSS) spectrum. The approval was subject to further testing and approval.

LightSquared cannot operate its terrestrial network until the FCC, "after consultation with NTIA, concludes that harmful interference concerns have been resolved and sends a letter to LightSquared stating that the process is complete." NTIA represents the President on spectrum management issues.

LightSquared, numerous federal agencies, and others spent much of 2011 testing GPS receivers in an effort to identify and mitigate the interference concerns. After the initial round of tests in early 2011 demonstrated the potential for widespread GPS disruption, LightSquared modified its signal plans, and the FCC and NTIA requested a second round of tests. These took place in late 2011, with the results raising continued interference concerns.

On February 14, 2012, the FCC announced that, based on the test results to date, it will not allow LightSquared's terrestrial operations, and it plans to withdraw LightSquared's ATC authorizations. The FCC solicited and received public comments on its plans, and is now expected to issue a final order on the matter. Learn more...

Actions: