LightSquared and GPS

Updated February 4, 2013

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?

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 due to concerns about harmful interference to GPS users. LightSquared, numerous federal agencies, and others spent much of 2011 testing GPS receivers against LightSquared's original and modified network configurations in an effort to identify and mitigate the interference concerns.

In February 2012, the FCC announced that, based on the test results and the assessment of NTIA (the agency that coordinates federal spectrum use), it would not allow LightSquared's terrestrial operations, and it planned to withdraw LightSquared's ATC authorizations. The FCC solicited and received public comments on its plans, but (as of February 2013) has not issued a final order on the matter. Learn more...

In September 2012, LightSquared submitted a comprehensive revision to its proposal 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. The FCC is seeking public comments on various aspects of LightSquared's latest proposal. Learn more...

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