LightSquared and GPS

NOTE: In 2016, LightSquared became Ligado Networks. This page contains information that is not current. We are retaining it for historical purposes without further updates.

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 faint 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 Jan 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 due to concerns about harmful interference to GPS users.

In Feb 2012, following extensive testing and analysis, the FCC announced it would not allow LightSquared's terrestrial operations and planned to withdraw LightSquared's ATC authorizations. The FCC solicited and received public comments on its plans, but (as of Aug 2013) has not issued a final order on the matter. Learn more

In Sep 2012, LightSquared proposed comprehensive changes designed to address the GPS community's concerns while allowing progress toward initial operation of the company's network. Among other things, LightSquared offered to permanently relinquish its upper channel adjacent to GPS in return for authority to operate at another band. In Dec 2012, the FCC relieved LightSquared of network build-out requirements established in Mar 2010. Learn more