Released: September 10, 2018
PS Docket No. 07-114
Comments: October 1, 2018
Reply Comments: October 11, 2018
The Public Safety and Homeland Security Bureau (Bureau) seeks comment on the vertical accuracy (z-axis) test bed report (Report), submitted by CTIA on behalf of the nationwide wireless carriers (AT&T Mobility, Sprint, T-Mobile USA, and Verizon) (the Carriers), and on the Carriers’ proposal for a z-axis accuracy metric submitted with the Report. The Carriers submitted the Report and their z-axis proposal to the Commission on August 3, 2018, pursuant to the Commission’s 2015 Wireless E911 Location Accuracy Fourth Report & Order, which required the Carriers to establish a test bed process to develop a proposed z-axis accuracy metric and to submit the proposed metric to the Commission for approval.
The Report, prepared by 9-1-1 Location Technologies Test Bed, LLC, the test bed administrator, describes the testing process used to assess vertical location solutions (the Report refers to this testing process as “Stage Z”) and provides the results of the testing. The Report states that two technology vendors, NextNav LLC (NextNav) and Polaris Wireless, Inc. (Polaris), participated in Stage Z to test technologies “that rely on barometric pressure sensor information from mobile wireless handsets to determine an estimated altitude of an indoor wireless 9-1-1 call.” The Report contains more detailed information on test procedures, data collected, and location accuracy test results for NextNav and Polaris. The Report also identifies issues that could be addressed by additional testing, and recommends further focus on three issues: (1) examining barometric sensor performance in a larger and more diverse sample of mobile devices; (2) developing production architectures for commercial implementation of z-axis solutions; and (3) assessing the feasibility of converting z-axis data to floor-level identification.
In their cover letter submitting the Report, the Carriers propose a z-axis accuracy metric of +/- 5 meters for 80 percent of fixes from mobile devices capable of delivering barometric pressure sensor-based altitude estimates. The Carriers contend that “Stage Z testing did not demonstrate that more accurate results can be consistently achieved across all testing regions, morphologies, weather conditions, and devices by the August 3rd, 2018 filing deadline.”
By this Public Notice, the Bureau solicits public comment on the Report and on the Carriers’ proposed z-axis accuracy metric. The purpose of the Public Notice is to gather information that will inform the Bureau’s recommendations to the Commission concerning next steps in the development of the z-axis accuracy metric contemplated by the Wireless E911 Location Accuracy Fourth Report & Order.