Out in Front: Dual Use, Single Front

April 1, 2011  - By

As it was in the beginning, now and always, and to the ages of ages — or at least into the conceivable near future: GPS was, is, and shall be a dual-use system.

Why, then, reading through the March 15 report of the Technical Working Group (TWG) to the FCC on LightSquared/GPS interference, do we find no mention at all of military receivers?

Presumably DoD and the GPS Directorate are both concerned and active on a separate front vis à vis the FCC, but what/how/when? Would it not be beneficial for the dual uses to present a united front in some way, or at least to collaborate to some extent? To observe, if nothing else, each other’s testing?

It turns out there are separate LightSquared/GPS Industry Council and government testing structures, the latter under under the National Space-Based PNT Systems Engineering Forum (NPEF), which will include military receiver tests. Several government members of the TWG are also members of the NPEF. The Executive Secretariat to the NPEF is also a core member of the TWG.

The two testing groups collaborate and try to be on the same page as to technical assumptions, test methodology, measures of effectiveness, and so on. They will observe and participate in each other’s tests as much as they can — with the exception of national security issues.

Testing of the military receivers is not a part of the TWG primarily because of classification. Any discussion of vulnerabilities of military equipment is generally classified at least at the Secret level.

Outside of the TWG, there have been direct meetings between LightSquared and the military officers leading the military receiver testing. The military have asked technical questions and LightSquared has answered them and provided examples of its hardware. LightSquared has flown technical experts to Colorado Springs to meet with HQ Air Force Space Command test leads.

“To the maximum extent possible,” said Anthony Russo, director of the U.S. National Coordination Office for Space-Based Positioning, Navigation, and Timing, “we’ll invite LightSquared to review test plans and make inputs on test methodology, but we do anticipate that some of the end results will be classified and therefore have to be conveyed separately to the FCC.”

“There is certainly good collaboration between the LightSquared-led TWG and the independent federal testing activities I directed under the NPEF charter. LightSquared has been extremely cooperative in supporting this,” he added.

In addition to classification issues, there are other reasons to do independent federal testing. LightSquared is focusing on the potential in-band overload issue, while the GPS community is concerned about any potential interference scenario — including out-of-band emission issues that LightSquared is not looking at.

Russo anticipates at least two reports will go to the FCC in June: “One from LightSquared where we make inputs, but have no official say on what they conclude; and one from me, based on NPEF results, submitted through the PNT EXCOM to the FCC. I expect the latter report to be at the Secret level, although we may be able to do a redacted version for LightSquared and the general public.”

This article is tagged with , , and posted in From the Magazine, Opinions

About the Author:

Alan Cameron is editor-in-chief and publisher of GPS World magazine, where he has worked since 2000. He also writes the monthly GNSS Design & Test e-Newsletter and the Wide Awake blog.

Comments are currently closed.