Ligado Recon Petitions Have Backers, Critics

the FCC approval, but contended the commission wrongly characterized it as endorsing the plan. It said it backed petitions for reconsideration of the approval that would substitute the 1 dB standard of GPS interference protection instead of "the impracticable 'performance-based' metric" the FCC went with. The recon petitions don't bring up new evidence that would justify reconsideration, Ligado consultant Roberson and Associates said. The various recon arguments -- including that 1 dB standard is more appropriate and that the GPS compatibility tests don't show GPS devices can operate without harm -- lack factual basis and are contrary to evidence presented in the order, it said. The Brattle Group, also a Ligado consultant, said the FCC “appropriately weighed the benefits and costs” of the license modifications. “The 23 MHz guard band, reduced power levels, and other conditions imposed on Ligado’s ATC network operations will drive down the potential cost of allowing low-power terrestrial deployment nearly to zero, as there appear to be limited interference concerns,” Brattle said: “Any potential remaining costs decline with time as they are mitigated and the stock of GPS devices turns over.” Aviation consultant JHW Unmanned Solutions countered arguments the modifications pose a threat to air safety. The FCC’s order “appropriately accepted the analyses of the Federal Aviation Administration, the expert Federal agency on issues regarding potential interference with aviation GPS devices and, more broadly, aviation safety,” the firm said: "Petitioners advance no legitimate challenge to the Order’s comprehensive analysis of these issues nor do they provide any new information.” Backers and opponents of Ligado's terrestrial wireless plans "seem to be talking past each other," with each side seemingly convinced it's in the right and puzzled by the opposition, the Resilient Navigation and Timing Foundation blogged Monday, citing letters from FCC Chairman Ajit Pai to House Armed Services Committee members (see 2005270045). The problem is "fundamental disconnects" in interpreting data, and there should be an independent expert evaluation of test results and a cost-benefit analysis, it said. Ligado said the FCC "fully consulted" with NTIA, considered its views and correctly rejected the proposed 1 dB standard, evaluating harmful interference by measuring actual performance.