Three-dimensional (3D) location has launched a second revolution in public-safety applications, promising an even greater impact than the launch of GPS technology decades before. It is worth examining how this technology works and what public-safety agencies should look for when considering the move to 3D location technology.
We are finally seeing the inclusion of the vertical, or Z axis, on technology road maps, enabling fully realized, 3D location tracking. Various location technologies in use are able to locate a target with floor-level — less than 3 meters — accuracy, the baseline for any public-safety application.
Imagine a scenario where a fire breaks out in a high-rise office building in the downtown area of a major U.S. city. Calls start to come in to the 9-1-1 system from people in the building, observers on the street and loved ones who have heard news reports. The public-safety agency needs a way to categorize these callers, identify the ones who are most in danger and locate the source of the fire in the building to extinguish it as quickly as possible. Which 3D location technology will help them best achieve these goals?
Device-based technologies work only on a specific operating system, such as Apple or Android. Device-based location services such as advanced mobile location (AML) typically use hybrid solutions that can incorporate GPS data, Wi-Fi access point locations, Bluetooth beacons, network-derived information and other sources. The algorithms that are used to calculate location are complex but well within reach of the computational power of smartphones. For this to become the universal solution, however, the industry would need to agree on a location format such as Presence Information Data Format Location Object (PIDF-LO), Internet Engineering Task Force (IETF) RFC 5491, and a standardized delivery interface.
Network-based technologies are device agnostic and do not have the limitations of platform-specific solutions. However, they require the deployment of specialized hardware within cellular network equipment and sometimes throughout the area being covered, which is both time consuming and costly, decreasing the appeal for budget-conscious public-safety agencies. In addition, some hardware solutions require specific changes to devices operating on these networks.
Hybrid technologies are software based and combine the best of device and network-based 3D location solutions. Because they incorporate inputs from a variety of sources using multiple location techniques, they are adaptable in diverse environments. For example, hybrid technologies incorporate Wi-Fi signals to increase accuracy. In our fire example, where the building’s Wi-Fi may be inoperable, the hybrid solution compensates by incorporating cellular signals and device sensors. Hybrid solutions typically produce the most accurate vertical location measurement and are in high demand from public-safety agencies.
Editor’s Note: The full version of this article, including five factors to consider when selecting Z-axis technology, will run in the February print issue of MissionCritical Communications magazine.
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