The Federal Communications Commission is moving forward with a proposal that mobile network operators must aim to provide the location of wireless 911 callers within three meters of the handset, for 80% of wireless 911 calls in the top 25 markets by April 2021 and the top 50 markets by April 2023.
The proposal calls for a higher level of accuracy than industry players had suggested, but not as accurate as some public safety representatives wanted; and some commissioners felt that it didn’t go far enough. The FCC’s proposed rulemaking says that the metric will “more accurately identify the floor level for most 911 calls, reduce emergency response times, and save lives.”
“Originally, the wireless industry proposed that our vertical location accuracy metric should be plus or minus 5 meters,” FCC Chairman Ajit Pai noted. “But based on the results of the tests that have been conducted to date as well as the input of public safety officials, I believe that a more stringent proposal is justified, and I have every expectation that our proposal will give our nation’s first responders the information they need to save lives.”
The FCC’s proposal, which received support from the three Republican members of the commission, comes after vertical location testing last fall. CTIA coordinates the test bed for the vertical (or z-axis) testing and the development of a z-axis accuracy metric, with testing conducted with two companies: NextNav and Polaris Wireless. Both rely on barometric pressure sensor information from mobile handsets to determine a caller’s estimated altitude.
Vertical axis testing took place late last year in the Atlanta, Chicago, and San Francisco regions (including rural areas). While the testing wasn’t quite comprehensive – Polaris’ solution couldn’t support iOS devices during the testing, and NextNav’s proprietary network wasn’t available in every test location – the final report from the testing found that the performance of the solutions “varied significantly depending on the specific approach to dealing with mobile device barometric pressure sensor biases and other error sources.”
The “single most important message of the testing,” according to the State Z Test report, was that active calibration – or continuous/ background calibration for each device – is “essential to achieve consistent and reasonable Z-axis estimation measurements for indoor wireless 9-1-1 calls due to mobile wireless handset biases that significantly affect the accuracy of barometric pressure-based estimation systems.” (The full test report is available here.)
Still, the test results were fairly in line with the expectations that the FCC sets out in the new proposed rulemaking.
“The test results showed that in 80% of NextNav test calls, vertical location was identified to a range of 1.8 meters or less, while 80% of Polaris test calls yielded a vertical accuracy range of 4.8 meters or less,” the rulemaking noted, while adding that Polaris’ performance “could likely be significantly improved should a more robust handset barometric sensor calibration approach [than that used in the test bed] be applied.”
Commissioner Michael O’Rielly noted the test results in his statement, saying that he supports the use of proven technologies in realistic timeframes — which he felt the current proposal does. “Currently, two vendors appear capable of providing vertical location accuracy results within three meters in some scenarios with a consistency that would comply with our rules,” O’Rielly said. “Early test bed results, however, do not support a two-meter z-axis metric, which was supported by some in the record. I plan on following this issue closely and will want to see that there is solid evidence to ensure that the metric the Commission eventually picks is feasible in the applicable timeframes.”
O’Rielly also indicated concerns about the potential privacy issues related to better location information and how it is stored and used. “This location accuracy proceeding,” he said, “is about providing first responders with life-saving information, not a vehicle to aggregate location information that can be provided to others.”
Commissioner Jessica Rosenworcel dissented from the FCC’s three-meter vertical accuracy proposal, arguing that the FCC’s rules governing 911 location technology are “behind the times” and “not ambitious enough.”
“The truth is a 3-meter policy does not provide public safety with precise floor location. As the text of the rulemaking acknowledges, it does not yield floor-level accuracy. I think that’s a problem,” Rosenworcel said. She went on to add, “I appreciate that this rulemaking has evolved since it was first put forward. It now includes a discrete question about floor levels. It also asks questions about privacy. But on the most fundamental level, it is organized around standards that unquestionably fall short of what first responders require to keep us safe.”
Commissioner Geoffrey Starks dissented in part and supported in part, saying that the proposal “still leaves about a 10-foot margin of error, which can send first responders to the floor above or below you. I’m concurring in part because this [proposal does not set out a clear path or propose a plan to get to a greater level of accuracy than 3-meters. Only floor level accuracy will give first responders the right tools to go to the right floor, the first time, every time. We need a plan to get there and that plan has to get it done as quickly as possible. The days where first responders don’t know what floor of a tall building a call for help is coming from must become history.”
Looking for more information on the latest developments in wireless technology related to public safety? Check out RCR Wireless News’ editorial report.
