A coalition of aviation, satellite communications and weather information users is still concerned about the threat of harmful interference from Ligado’s proposed ancillary terrestrial component (ATC) service despite Ligado’s pledge to protect GPS aviation and other GPS devices.
The letter from the coalition (PDF) was signed by 27 national organizations and companies, including the National Weather Association, Iridium, Gogo Business Aviation, Lockheed Martin and the National Emergency Number Association (NENA).
They said the record makes clear that interference will be particularly impactful to government and commercial entities that rely on GPS and satellite communication services for aviation safety and other critical services. Groups that receive and depend on real-time weather and related environmental information from National Oceanic and Atmospheric Administration (NOAA) satellites will be affected, they say.
“Whether the interference is to public safety communications, systems relied on by planes, helicopters, drones, ships or weather buoys, interference with SATCOM systems must not be permitted,” the coalition told the FCC.
Ligado has 40 MHz of licensed spectrum in the nationwide block of 1500 MHz to 1700 MHz spectrum and it wants to provide terrestrial service using spectrum that was originally allocated for satellite operations. In May, it proposed a modification that has to do with limiting power in the 1526-1536 MHz band; that amendment was the result of lengthy consultations with the FAA and Department of Transportation and is intended to protect GPS users.
While a lot of entities are now backing Ligado, it’s still getting pushback from the coalition. Separately, Iridium said Ligado’s amendment doesn’t resolve the interference concerns that Iridium has raised in response to Ligado’s proposed operations in the 1627.5- 1637.5 MHz band. Nor does the amendment address the concerns of the many groups that receive real-time weather and related environmental information from NOAA satellites who have expressed concerns, Iridium said.
“In short, Ligado’s latest filing—and the eight years of filings before it—does not meaningfully address the harmful interference that its proposed terrestrial service will cause to numerous parties,” Iridium told the commission (PDF). “As a result, Ligado’s application should be rejected.”
Ligado has said it plans to invest up to $800 million in its satellite and terrestrial network capabilities. If approved, the company would focus on targeted deployments that deliver highly secure and ultrareliable communications over custom private networks, serving industrial IoT and emerging 5G markets, in areas such as rail, trucking, utilities, public safety and oil and gas.
Last month, the Helicopter Association International (HAI) and 10 other aviation-related associations said they were concerned that Ligado’s proposed network will pose interference issues for aviation. They pressed for thorough assessment and testing to address their issues and insisted that empirical data, obtained from credible industry-accepted standards, be obtained.
For its part, Ligado, in its July 19 filing (PDF), ticked off a number of concerns raised by various stakeholders and concludes that they’ve been resolved. It also said recent filings by satellite communications and weather parties simply rehash arguments that Ligado already addressed.
And when it comes to some of the aviation concerns? Ligado noted that pilots should not rely on GPS devices when they’re near obstacles—they should be using their own eyesight to see their surroundings.
Ligado said it has worked with other stakeholders to ensure the FCC’s record is complete and the time is right to move forward.
“Ligado’s proposed operations will protect certified aviation GPS devices, all other GPS devices, and will not create harmful interference to other services operating near Ligado’s spectrum,” the company told the FCC. “The Commission now has a record to approve the Modification Applications as amended.”