Ag Community Increasingly Concerned with Threat to GPS

May 27, 2011 Bookmark and Share

Representatives from major agricultural organizations met this week in Washington to hear about potential interference with GPS systems if a pending waiver is granted.

In 2010, LightSquared, a company formerly known as SkyTerra that works on wireless broadband, asked the Federal Communications Commission (FCC) to allow it more on-land use of the electromagnetic spectrum, including an area bordering that used by GPS devices.

GPS is a collection of satellites maintained by the U.S. government but used by an extremely wide range of industries and individuals.

In recent years, precision farming has incorporated extensive use of GPS devices, providing enormous efficiencies particularly in decreased use of fertilizers and pesticides.

Early this year, LightSquared received a conditional waiver allowing part of its project to move forward and putting other parts on hold due to concerns about interference with GPS devices.

If the proposed changes are made, tests show GPS interference could occur because of what are called “out of band emissions” – meaning signal leaks from one band into another – or from “front end saturation” – meaning receivers take in signals from another band.

These problems will increase as the GPS device gets closer to a LightSquared tower and as more towers are erected. In effect, it will mean GPS devices will become less accurate and perhaps quit working altogether.

The serious concerns this has created have spurred research by the government and a number of companies. In addition to a scientific challenge, this is also a political and economic one, since the U.S. government generates revenue from users of the electromagnetic spectrum.

The release of additional research on the problem from LightSquared and federal government testers, who are working with the company and the GPS Industry Council, is anticipated in mid-June.

The briefing this week was held by the National Executive Committee for Space-Based Positioning, Navigation and Timing (PNT), which is an interagency federal organization that works on GPS issues.

Attendees included a wide range of agricultural representatives, many of whom are now working together with other major GPS users from airline operators to land surveyors. Members of Congress are also well aware of the interference issue, with more than 30 Senators led by Senate Agriculture Committee Ranking Member Pat Roberts (R-Kan.) writing the FCC on the issue last week.

To read a recent letter on GPS concerns sent to the FCC by NAWG, please visit