LightSquared and GPS
NOTE: In 2016, LightSquared became Ligado Networks. This page contains out-of-date information that is no longer correct. We are retaining it for historical purposes without further updates.
- Jul 2014: NTIA sends letter to FCC transmitting DOT concerns about LightSquared handsets
- Jun 2014: FCC hosts workshop on GPS Protection and Receiver Performance Learn more at FCC.gov
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?
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
Select a time period to view relevant documents from that stage in the process:
- 2001 – 2010
LightSquared ATC authorizations prior to FCC waiver
- Nov 2010 – Jan 2011
LightSquared request and FCC waiver order
- Early 2011
First round of GPS interference testing
- Mid 2011
Proposed changes to LightSquared's operating plan
- Late 2011 – Early 2012
Second round of GPS interference testing
- Late 2012 – Mid 2013
Further changes to LightSquared's proposal
- Mid 2013 – Mid 2014
Assessment of LightSquared handsets
- Jun 2014: Presentations from FCC workshop on GPS protection and receiver performance
- Apr 2012: U.S. presentation from International Satellite Navigation Forum
- Jan 2012: NOAA presentation on high precision GPS testing
- Jan 2012: NOAA LightSquared update to Federal Geodetic Control Subcommittee
- Nov 2011: Panel discussion at PNT Advisory Board meeting
- May 2011: Presentation to PNT Advisory Board on initial NPEF test results
- Mar 2011: MITRE presentation from Munich Satellite Navigation Summit
Congressional Hearings & Legislation
- LightSquared-Related Legislation
- Sep 2012 Hearing on FCC Decision-Making on LightSquared Issue
- Feb 2012 Hearing on GPS Aviation Issues
- Oct 2011 Hearing on LightSquared Impacts to Small Business GPS Users
- Sep 2011 Hearing on Sustaining GPS for National Security
- Sep 2011 Hearing on LightSquared Impacts to Federal Science Activities
- Jun 2011 Hearing on GPS Reliability for Transportation
FCC Public Comment Dockets
Includes comments on LightSquared applications to modify ATC authority to reliquish its upper channel near GPS and relocate operations to another band (Nov 2012)
Includes comments on LightSquared request for public rulemaking to allow transitional use of its lower channel near GPS (Nov 2012)
Includes comments on LightSquared request for spectrum allocation change at 1675-1680 MHz (Nov 2012)
Includes comments on LightSquared's request for relief from 2010 terrestrial network build-out conditions (Oct 2012; FCC order issued Dec 2012)
Includes comments on: FCC-ordered working group report (Jun 2011); LightSquared recommendations (Jun 2011); LightSquared petition for declaratory ruling (Jan 2012); NTIA letter and test results (Feb 2012); and FCC plans to withdraw LightSquared ATC authorizations (Feb 2012)
Includes comments on LightSquared's petition for declaratory ruling (Jan 2012)
Includes comments on LightSquared waiver request (Nov 2010) and many other topics, including those listed above