Inside GNSS Media & Research

JUL-AUG 2018

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20 Inside GNSS J U L Y / A U G U S T 2 0 1 8 T here was a f lurry of filings Ju ly 9 just as t he w i ndow closed for public comment on Ligado Net work s' pro- posal to repurpose satellite frequen- cies for a terrestrial network — a plan with the potential to interfere with GPS receivers. The comments emerged as specu- lation swirled around a July 3 bid by EchoStar for Ligado spectrum supplier INMARSAT. e bid was rejected and, as of press time, EchoStar will have to wait six months before trying again. That doesn't mean the game is up. I NM A R SAT holds t he l icenses for L-band spectrum that Ligado has a con- tract to use. Investment analysts have been speculating that Charlie Ergen, the telecommunications powerhouse behind both EchoStar and the Dish Net- work, will use Dish to try again to buy INMARSAT. His objective likely has to do with spectrum and not corporate synergies, surmised a bevy of industry watchers. Experts at Quality Analytics suggested Ergen could be trying to protect the value of his firms' current spectrum holdings from being driven south by a sudden inf lux into the market of L-Band fre- quencies. A deal for INMARSAT could also give Ergen more leverage with Liga- do. Ligado has long been suspected of being more interested in selling its fre- quencies than building a network and Ergen tried to gain control of Ligado's L-Band spectrum during the bankruptcy of its predecessor firm LightSquared. Final Pitch Meanwhile Ligado's plans remain mired at the Federal Communications Com- mission (FCC) where the argument con- tinues over whether the proposed ground network will cause widespread interfer- ence to GPS. In its July 9 comments Ligado assert- ed it had addressed those concerns. Ligado underscored that a month ear- lier it asked the FCC to cap at 9.8 dBW (10 Watts) the power at its proposed ter- restrial base stations operating in the 1526-1536 MHz band ("Lower Down- link Band".) This, the firm said, was a reduction of more than 99.3% from the nominal 32 dBW EIRP maximum set forth in its earlier applications to build a ground-based network. The change, the company wrote in the May 31 request, is "consistent with" the Department of Transportation's (DOT's) Globa l Positioning System Adjacent Band Compatibility Assess- ment (ABC Assessment) and "benefits not only certified aviation devices, but all GPS receivers." "e (power reduction) Amendment assures protection for certified avia- tion GPS receivers as well as all other GPS receivers," the company wrote in its July 9 comments. "is conclusion is supported by the certified aviation recommendations of the DOT Report, Ligado's coexistence agreements with major GPS manufacturers and thou- sands of hours of empirical testing, all of which evidence that all other classes of GPS devices will not be adversely affected by Ligado's revised operational parameters." It is wor t h not i ng t he ca ref u l ly worded assertion that "all other classes" of GPS devices will not be adversely affected — as opposed to saying all GPS receivers will be unaffected. Lidago's own tests indicate there could be issues. So, to ea se opposit ion t he f i r m offered in its filing to repair or replace any impacted government receivers. It is unclear what will be available for the millions of non-government users. Among those seemingly le out are sev- eral million commercial and hobbyist drone pilots now operating in the U.S. The smaller drones favored by these groups do not use certif ied aviation receivers. Ligado Fight Comes Down to Choice of Interference Standard DEE ANN DIVIS Dee Ann Divis has covered GNSS and the aerospace industry since the early 1990s, writing for Jane's International Defense Review, the Los Angeles Times, AeroSpace Daily and other publications. She was the science and technology editor at United Press International for five years, leaving for a year to attend the Massachusetts Institute of Technology as a Knight Science Journalism Fellow. WASHINGTON VIEW

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