Weather Critics of Ligado's TLPS Plans Still See Red Flags

Titley said that whenever challenged by dozens of people in the weather community who raise concerns, Ligado says that "you weather guys don't understand the physics.” Titley said he was "very leery" of believing Ligado's proposed protection zones, calling them part of "the camel's nose under the tent" that would allow it to operate in that frequency band though addressing any interference issues that might come up afterward would be very difficult to deal with.

While the satellite firm has made clear that uplinks from thousands of ground-based sensors won't face interference from Ligado's TLPS plans, "the real impact is not going to change if you can't get the data down" because of lost access to or degraded data from NOAA satellites, said Bill Mahoney, a commissioner on the American Meteorological Society's Weather, Water and Climate Enterprise Commission. Mahoney said the weather community is concerned about the lack of details or specific designs for any kind of terrestrial system for distributing data from federal earth stations, especially such issues as who would bear such possible expenses as dedicated fiber optic lines.

Multiple weather interests questioned the reliability of a cloud-based content distribution network (CDN) as proposed by Ligado compared with getting the weather data directly from NOAA's Geostationary Operational Environmental Satellite (GOES) system. Data reliability and timeliness is why some Microcom Design customers opt for getting ground stations, said Brett Betsill, president of the maker of hardware and software for accessing GOES data. The National Interagency Fire Center in Idaho accesses NOAA data via the Internet, NOAA's low-rate information transmission system and a direct readout ground station, since LRIT can have a 20-30 second latency and Internet "is even larger than that," Betsill told us. "Ninety-nine percent of the time, the Internet is just fine," but shouldn't be relied on for delivery of data in public safety or life-threatening situations, he said. Pointing to severe weather events like hurricanes, Titley said, "One of the things you lose completely is Internet access and cellular phone access. [A CDN] is not going to work when people need it -- that's what people have been trying to tell Ligado.”

A hardened system that would transmit GOES data at low latency and high reliability is possible, Titley said, "But who is going to come up with the billions of dollars? There is no path that has the resources to make this work. We see no investment by Ligado to build a network that would run at that reliability.”

While the GOES data collection system uplinks in the 401-402 MHz band, it transponds to 1679-1680 MHz, and any interference to the downlink would mean the data would be lost since it is not otherwise stored or used by the satellite, one space industry engineer told us. The engineer said protection zones broadly have to consider anomalous propagation effects -- such as interference from hundreds of kilometers away -- that can happen when a receiver sits near a water body, the engineer said. Ligado has proposed use of protection zones as a way of protecting earth stations of federal users of NOAA data.

A cloud-based CDN "can be designed to meet and exceed the latency and reliability requirements of the existing NOAA systems," Ligado said Monday, adding that a fiber optic system eliminates any delay due to latency. "The cloud-based system we are proposing is widely used today by many sophisticated commercial entities -- from sensitive and time-demanding financial institutions to high-value video content -- and is perfectly suited for critical uses. As for cost, the FCC should require the auction winner to fund this solution.”

Pointing to concerns about protection zones, Ligado said the FCC should issue an NPRM, calling it "the best way to be sure issues like this are fully explored and addressed." The NPRM process "is intended to identify issues like this one and establish guidelines to ensure compatibility across all spectrum bands, including through the use of protection zones," the company said "The FCC has used this same approach in other settings, including recently with sensitive Navy radar tracking stations. We expect a similar process would ensure that NOAA’s operations are protected.

Some of the firm's critics in the weather sphere "may not understand all the ins and outs" of spectrum use, with many of them concerned about lack of NOAA data affecting their weather-related businesses, said Al Wissman, NOAA branch chief-data management and continuation of operations, in an interview. But, he added, "You want to make sure you don't throw the baby out with the bath water -- let's make sure it's the right [spectrum] and not the stuff used for critical infrastructure." Pointing to a redesign of the just-launched GOES-R satellites to accommodate the sale of the 1695-1710 MHz band as part of the AWS-3 auction, Wissman said the agency has "a very narrow band in that overall spectrum we get to work with -- we are very sensitive to losing that or having to share some of that because of the lack of ability to be able to do our job.”

NOAA hopes to see federal funding to undertake a study of who are the nonfederal users of the agency's GOES data and what applications use that data, Wissman said. NOAA also wants to study what means exist for mitigating interference particularly related to ionosphere reflection, where the cause of interference might be large distances away, potentially negating any benefits of protection zones, he said.