911 — How high are you?

Altitude is not reported on 911 calls. If you're in high-rise, public safety has no way of knowing what floor you're on. That could be the difference that saves your life.

911 — How high are you?
Credit: Stephen Lawson

Reaching 911 can mean the difference between life and death. But just connecting to the 911 center is only half the battle. Determining your location is the other half.

Despite the cool technology we see on TV and in the movies, when you make a 911 call from a cell phone, in actuality you are the proverbial needle in the haystack—and that haystack is in a dark room, and 911 has no flashlight.

+ Also on Network World: Why smartphones struggle with 911 +

Each year in the U.S., citizens make about 240 million 911 calls, with an estimated 192 million of them originating from cellular phones. With 911 Public Safety Answer Points (PSAPs) reporting inadequate location on these calls, it is no surprise that this presents a unique problem for public safety officials. 

In an emergency, the most critical piece of information is the location. Both the proper routing of the caller and the dispatch resources needed are determined by this crucial data. The problem that plagues even the most modern centers is that this information is often anecdotal in nature and challenging to validate. For example, plotting the ‘X and Y’ coordinates—longitude and latitude—on a map is possible, but the accuracy level of the coordinates will vary significantly based on the call and the carrier.

Furthermore, a third dimension known as "Z," or altitude, is absent from every call today because the cell phone cannot measure or report this information to public safety centers.

Therefore, location reporting remains two-dimensional. We correlate left and right, forward and back, or east and west, north and south—especially when dealing with maps. While this logic has worked in the past, the lack of a Z indicator for altitude creates an additional problem. How do dispatchers accurately direct fire or police when the cell phone caller is in a high-rise building? 

Try this as an exercise:

Cut and paste the global GPS coordinates of 25.1972° N, 55.2744° E into Google. Hitting Enter, you should be magically transported to Dubai. Here, you will be at the base of the tallest building in the world, the magnificent Burj Kalifa with 160 stories of commercial businesses, offices and even luxurious residences towering above the Arabian dessert.

The Burj provides an excellent example of how altitude has a significant value. If during an emergency, only the X and Y coordinates, are given, there would be 160 identical locations located at 25.1972° N, 55.2744° E. Certainly a challenge for any first responder to decipher.

Notwithstanding the actual office location on a particular floor, if the floor number is not correct, you might as well be in a different building, altogether.

The problem comes down to the lack of information flowing from the caller’s phone to the PSAP and those who need it: the police dispatchers. With calls originating from high-rise buildings, PSAPs desperately need altitude information to dispatch emergency service efficiently. However, this data just doesn’t exist on any call today.

Euler Diagram

What does exist is a mathematical technique called trilateration. The information from each cell tower is collected and used to create a Euler diagram. The examination of multiple data points will then produce a very accurate reading of location. Beacons and Wi-Fi access points installed in buildings can create additional references that can create a remarkable resource providing reliable X, Y and even Z information to first responders. The databases already exist today with Google, Apple and Skyhook all maintaining their versions. However, creating these databases is not a simple task, and the revenue model for the database administrators has yet to be determined.

Getting the data — The chain of care

Collection of the data: This is certainly the easiest step, as this problem is likely solved already. Many smart devices have been collecting and storing information about the carrier networks they see, cross-referencing Wi-Fi BSS ID tags and, if the GPS signal is valid, latitude and longitude information for years.

The cellular chain of care Mark J. Fletcher, ENP

Transportation of the data: Assuming data points are available, a way of passing that information along needs to exist. With the help of our new friend the internet and LTE data connections being fairly ubiquitous, our digitally connected world solves the first two challenges.

Termination and use of the data: Once we get data where it’s needed, applications need to be able to read it, process it and request additional information, if necessary.

The Federal Communications Commission acknowledged the problem and attempted to address their segment of the chain they are most directly responsible for, the data transport network. In the FCC 4th Report and Order, published in February 2015, the following requirements were passed, affecting national Commercial Mobile Radio Service (CMRS) providers—more commonly known to you and me as cellular carriers.

Horizontal location

All CMRS providers must provide (1) dispatchable location, or (2) x/y location within 50 meters, for the following percentages of wireless 911 calls within the following timeframes:

[Jan. 29, 2017]: 40 percent of all wireless 911 calls

[Jan. 29, 2018]: 50 percent of all wireless 911 calls

[Jan. 29, 2020]: 70 percent of all wireless 911 calls

[Jan. 29, 2021]: 80 percent of all wireless 911 calls

To deal with the issue of multi-story buildings, the FCC Report and Order also makes an initial attempt to addresses vertical location by 2018.

Vertical location

All CMRS providers must also meet the following requirements for provision of vertical location information with wireless 911 calls, within the following timeframes:

[Jan. 29, 2018]: All CMRS providers must make uncompensated barometric data available to PSAPs from any handset that has the capability to deliver barometric sensor data.

[Jan. 29, 2018]: Nationwide CMRS providers must use an independently administered and transparent test bed process to develop a proposed z-axis accuracy metric, and must submit the proposed metric to the Commission for approval.

Clouding the issue somewhat is the next clause that talks about how widespread this technology must be deployed. In addition to six years being a lifetime in the IT business, limiting this to the top 25 markets places a pretty small fence around the technology and its availability to the American public and their 192 million cellular emergency calls a year.

 [Jan. 29, 2021]: Within six years: Nationwide CMRS provides must deploy either:

[D]ispatchable location, or

[Z]-axis technology that achieves the Commission-approved z-axis metric, in each of the top 25 Cellular Market Areas (CMAs)

And an additional two years to double that penetration:

[Jan. 29, 2023]: Nationwide CMRS providers must deploy dispatchable location or z-axis technology in accordance with the above benchmarks in each of the top 50 CMAs. 

Adding dispatchable location reference points

Where does dispatchable location information need to be used?

The National Emergency Address Database (NEAD) must be populated with a total number of dispatchable location reference points in the CMA equal to 25 percent of the CMA population.

Where z-axis technology is used: CMRS providers must deploy z-axis technology to cover 80 percent of the CMA population.

Non-nationwide carriers that serve any of the top 25 or 50 CMAs will have an additional year to meet these benchmarks.

Doing the math

HBO’s John Oliver blasted the carriers in a recent This Week Tonight Episode. Oliver jokingly pointed out that in five years' time, we’ll find you 80 percent of the time. In reality, unless you’re at ground level and outside in an open field, guaranteed accuracy will be applicable only in the top 50 markets. So, don't hold your breath. Literally.

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