Public Safety Forward to CSRIC Report

The following is the Public Safety Forward from the CSRIC Indoor Location Test Bed Report.  The full report is available here.

The Public Safety representatives on WG3 agree that the Test Bed objectives of conducting an unbiased test to verify location accuracy in various structure types and morphologies were fulfilled with the Test Bed. The results demonstrate the current capabilities and limitations of location based technologies participating in the Test Bed. While the location positioning platforms tested provided a relatively high level of yield, as well as improved accuracy performance, the results clearly indicate additional development is required to ensure the positional coordinates provided on an emergency caller sheltered indoors result in an “actionable location” for emergency response, especially in urban and dense urban environments. An actionable location can vary based on the type of emergency incident and requiredresponse, but an essential element, in addition to location accuracy, is the ability to provide high reliability and consistency of data (often captured as a low “uncertainty” metric), such that both telecommunicators and first responders have confidence in the underlying information.

Public Safety desires reliable and consistent caller location information to a specific dispatch-able building (and floor in multi-story environments). Lacking the specific building and floor, the desire would be for the smallest possible search ring, but still with the underlying requirement for confidence in the reliability and consistency of the data. In high building density environments (such as dense urban and urban morphologies), even a small search ring may still encompass multiple adjacent buildings, while in less dense environments (particularly rural), a somewhat larger search ring may still be sufficient to identify a single structure. Further, floor level vertical accuracy is valuable in large multi-story structures common in urban and dense urban morphologies, but is of lesser importance in rural morphologies and single family structures.

Horizontal positional accuracy within 50 meters can provide a meaningful indoor location, particularly in rural or suburban environments, but as the results of the Test Bed demonstrate, even this accuracy within heavily urbanized areas or downtown settings may still result in positions outside the actual building where the emergency call originated. Horizontal positional fixes that substantially exceed 50 meter accuracy, provides only general location information. Tighter performance is required, particularly in urban and dense urban environments to narrow the search ring to a single building or a more reasonable number of adjacent buildings. The test bed results show significant promise with respect to high yield, relatively high confidence factors and reliability for the technologies tested. Additional work is required that incorporates emerging technologies into future, long term test bed processes.

The current results involving emerging technologies demonstrate the ability to achieve improved search rings in the horizontal dimension (often identifying the target building, or those immediately adjacent). Substantial progress in the vertical dimension (67th percentile of 2.9 meters, or approximate floor level accuracy) was also demonstrated by one emerging technology through the use of locally calibrated barometric pressure sensors in the handset. The availability of such functionality would be an important factor in locating indoor callers in urban and dense urban multistory buildings. Public safety recognizes that additional work remains before actionable altitude measurements can be broadly provided and utilized to aid first responders, including standardization, commercial availability, and deployment of such technologies. Public Safety expects that the standardization, commercial availability and deployment of such technologies are priorities for all stakeholders. The incorporation of accurate vertical dimension (Z axis) coordinates into public safety GIS systems would further assist in refining the caller’s location and in some cases may well assist in eliminating adjacent properties as the call origination point.

The processes and procedures used to coordinate and establish the Test Bed should be used as a baseline for recommended future indoor accuracy studies. It is imperative the processes used are repeatable and technology neutral, thus allowing future test bed initiatives to follow the same processes regardless of the type of technology represented in the test. However, Public Safety acknowledges that wide-spread indoor accuracy testing is not practical, considering the challenges with building access, logistics and time required to perform and analyze the test results as encountered in the current Test Bed. A process of small-scale test beds and statistical sampling mutually designed and agreed upon by Public Safety, location determining equipment vendors and wireless carriers will most likely provide the best vehicle for future studies.


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