“Protect the adjacent bands to GNSS as a quiet neighborhood” is one of the core principles of RNT Foundation’s Protect, Toughen and Augment recommendations to safeguard our invaluable GPS/GNSS services.

Consequently we were very glad to see the Department of Transportation advancing its “Adjacent Band Compatibility (ABC) Study” to determine what transmissions could be allowed in these frequencies.

We were less glad to see the Federal Communications Commission (FCC) processing proposals for non-satellite (i.e. high power) broadcasts in those very frequency bands, without the results of the government study. At least the FCC asked for the public’s comment on the proposals by a company called Ligado.

Representatives of Ligado discussed their proposal this week at the 17th meeting of the U.S. National Positioning, Navigation and Timing Advisory Board. They claimed their study showed the proposed transmissions would have little to no impact on GPS users.

At this meeting Ms Karen Van Dyke from the Department of Transportation also discussed the government’s on-going ABC Study.

We were not convinced by the Ligado presentation, and thought that perhaps the government ought to devote more money and people to its independent study. It seems clear that (1) the FCC should hold all such proposals in abeyance until the ABC Study is complete, and (2) that the FCC should regard navigation signals as unique and distinct from communication signals and consider different criteria for evaluating possible interference.

Here’s  the comments we submitted to the FCC.

Thanks to everyone who helped to refine all of our drafts over the weekend!