Inside GNSS Media & Research

JUL-AUG 2019

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20 Inside GNSS J U L Y / A U G U S T 2 0 1 9 WASHINGTON VIEW high-level, policy body with represen- tatives from nine different agencies that coordinates GPS-related mat- ters to ensure the system addresses national priorities as well as military requirements. Parkinson presented an analysis to the board showing what it would take to protect the most sensi- tive GPS receivers under the cur- rent Ligado plan. Ligado has made some changes since 2015 including announcing in 2018 that it was cut- ting its initial transmitter power to 10 watts. Based on that information, and test results from the Department of Transportation's Adjacent Band Compatibility (ABC) Assessment, Parkinson looked at the impact to the receivers used for high precision, high productivity applications such as precision agriculture, robotics, machine control, scientific applica- tions—including sensitive weather probes—as well as commercial tim- ing, survey and mapping. (Parkinson called the ABC tests "the only credible set to allow calculations." Released in May 2018 the study showed the power levels that could be tolerated by 80 representative GPS receivers. It can be found at https://www.transportation. gov/pnt/global-positioning-system- gps-adjacent-band-compatibility-as- sessment) During his presentation Parkinson noted that configuration of the Ligado network, which is critical to deter- mining interference, remains unclear. ough asked more than once Ligado Executive Vice President Valerie Green provided little insight into how the network would be laid out when she spoke to the Board's November 2017 meeting. Inside GNSS did reach out to Ligado for more information about its network, and any other details or comment the firm might offer for this story, but did not get a response. At 10 watts Parkinson said that the towers for the network would have to be spaced 12 miles apart to protect the high precision GPS receivers in 90 per- cent of the covered region. at is he assumed receivers would be impacted in some 10 percent of the covered region. Conversely, if Ligado wanted to place the towers closer together the power would have to be reduced to get the same level of protection for GPS users. For example, he said, if the tow- ers were spaced 200 meters apart then the initial transmitter power level of the signal would have to drop to less than a milliwatt. "What about other classes of GPS receivers? e story is slightly bet- ter but nonetheless not very good," Parkinson said. e only type of receiver that makes it, he said, is in cell phones, which don't have the same accuracy requirements. "So the conclusion is inescapable, in my opinion," Parkinson said. "It just further strengthens our previous recommendation. Reject the 10 watt proposal. It does not meet the ExCom's goal of protecting existing and evolv- ing uses of space-based PNT service. It's not even close." Section 7 e newest and most interesting development in the Ligado contro- versy is the company's June 25 request for a decision under Section 7 of the Communications Act. Added to the Act in 1983, Section 7 has two mandates: 1) It directs that the Commission determine whether a proposed new technology or service is in the public interest within a year aer a petition or application is filed. 2) It puts the burden to demonstrate that such a proposal is not in the public interest on any person or party opposing a new technology or service. $2 Billion Lawsuit Over Ligado Frequencies Discontinued A judge has discontinued a $2 billion lawsuit alleging "massive fraud" in a deal that laid the foundation for LightSquared and its successor firm Ligado Networks. Harbinger Capital Partners, LightSquared's key backer, is alleging that Apollo Global Management LLC, knew or should have known that a terrestrial network built on the frequencies at the heart of the deal would interfere with GPS receivers. Those frequencies were held by SkyTerra, which Apollo Capital sold to Harbinger. Harbinger said Apollo and affiliated parties learned in 2001 after private tests were done, that voice and data signals on those frequencies would overload GPS receivers. They also knew about additional tests done by DIRECTV in 2007 that confirmed the findings. Harbinger alleges that those results were concealed, however, when Apollo sold it on a plan to buy SkyTerra and use its frequencies to support a ground network as well as satellite communications. "We believe the suit lacks merit and we intend to defend ourselves vigorously," said a spokesperson for Apollo Global Management in a written statement shortly after the suit was filed in December 2017. Though Ligado was not part of the suit the issues raised before the court could make it very hard for the Federal Communications Commission to grant Ligado a modification to its license for those frequencies," said Tim Farrar, a technology consultant specializing in the satellite industry who has followed Ligado closely. Nothing has come of the suit, however—at least not yet. After a series of mutually agreed to but repeated stays, the court discontinued the matter without prejudice on June 25.

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