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Use existing functionality in Smartphones to locate emergency callers

Published November 03, 2016

To accurately locate emergency callers from mobile phones – is increasingly urgent across the globe as mobile phones are ubiquitous in many countries.

How does it usually work today?

When you call an emergency number the dispatcher/telecommunicator is asking you where the emergency is located. This is a crucial piece of information for carry out any form of emergency action to respond to your situation.

At the same time/or during the call is recieved by the PSAP (Public Safety Answering Point) the wireless carriers will also provide with a location information from the callers phone number. The accuracy of the returned location data varies a lot due to a number factors, to name a few.

- Density of cellular towers where you are currently are calling from

- Technology deployed by the carriers in terms of LBS (Location-Based Services)

- Laws and legislation, whom can enforce better caller accuracy from the carriers

(Graphics shows Enhanced 9-1-1)

New Technology

When new technology emerging it usually creates gap between the old and new which sometimes is hard to bridge with existing solutions. A key success factor for emergency services is to be able to use new technology to improve public safety which can be a challenging task due to number of reasons. Using modern web technology such as HTML5 can bridge this gap at some level.

One example of HTML5 is the Geolocation functionality. This is feature enable any website to access the same location data as with native apps. This means that the built in web browser is enough to share a precise location only by visiting a website and approve this information to be shared with the website.

Using a web solution to identify a caller location will of course not cover all scenarios since the caller sill need to be connected to the Internet and have access to a Web browser. But as the citizen are getting more and more connected with smartphones this will become lesser of a problem.

The trend is clearly pointing in this direction. In October 2016 the mobile and tablet internet usage exceeds desktop for the first time worldwide according to the StatCounter Global Stats.

About 70% of 911 calls are placed from wireless phones, and that percentage is growing (FCC)

Caller Location Technology

Automatic Location Identification (ALI)

ALI will automatically query database(s) to find any addresses connected to a phone number. If you are outdoors using a mobile phone this information might not be relevant to determine your current location, though it can be used for other purposes but not to determine the actual caller location.

Network based

This is the most common way of locating a wireless caller is done by the carriers. The accuracy of the caller varies a lot depending on the deployed technology in the network, handset capabilities and rules and legislation in the specific country.


Advanced Mobile Locator will send a single location update to the PSAP via SMS (Google/Android can also use Internet) when calling 112 automatically. The location is directly derived from the handset which makes it a great improvement when a location is available on the handset.

To make AML available in countries a joint effort is required from Google, Carriers and PSAPs to have this impmenented. Currently this solution only works with Android OS and specific countries where this feature has been activated. As of to date Estonia and the United Kingdom has fully rolled out this feature, but more EU countries are in progress of rolling it out.

112 Apps

Emergency apps can provide the location data with great accuracy, but ofcourse it needs to be downloaded installed and configured before you end up in an emergency. Other aspects when using app solutions is that they might be bound to a local/nation wide PSAPs which can cause discrapency where your location data is sent when you are outside this geographically boundaries. Meaning your call ends up in one PSAP and location data in another PSAP. This is something EENA has addressed in the document (PEMEA) Pan-European Mobile Emergency Application.

HTML5 Geolocation

With high penetration of Smartphones users with modern web browsers that supports the HTML5 Geolocation functionality makes this it this a viable way of acquiring a high precision handset derived location data only by visiting a website. Since the process can be initiated by the PSAP, the location data will be exchanged directly between the caller and PSAP which makes this an effective solution when it works.

So what to use?

To summarize all the different ways of locating a wireless caller there are no perfect solution today that will cover all cases 100% with the caller privacy intact. I believe that mixing different solutions to different scenarios will have a big positive impact to emergency services moving forward.

HTML5 Geolocation in depth

The Geolocation functionality is a subset of the HTML version 5 standard released in 2014 by the W3C which has representatives from vendor such as Google, Apple, Microsoft (world wide web consortium) to make the web more accessible and feature rich experience. But a working draft of the Geolocation implementation has been around in web browsers since 2009. Also the HTML5 also supports functionality such as video and audio in the web browser.

The Geolocation functionality exposes a set of methods that can be invoked by standard web technology in browsers that supports HTML5. Sometimes it can even be used on a laptop/desktop connected to a Wi-Fi in a densely populated area to acquire a location using the nearby Wi-Fi base stations to calculate a location.

To mitigate privacy concerns, all requests that are made to the HTML5 Geolocation functionality requires a consent between the user and the website for accessing any location data available to the browser. This is process is initiated by the website but handled by the browser which basically is asking the user to permit or deny to share this information with the website.

What information can be derived from HTML5 Geolocation?

The geographic coordinate reference system used by the attributes in this interface is the World Geodetic System (2d) [WGS84].

  • The latitude and longitude in decimal degrees.
  • The accuracy and altitudeAccuracy (95% confidence level).
  • The altitude height of the position, specified in meters (optional)
  • The accuracy level of the latitude and longitude coordinates. (optional)
  • The altitudeAccuracy attribute is specified in meters. (optional)

  • The heading attribute denotes the direction of travel specified in degrees
  • The speed is device’s current velocity and is specified in m/s. (optional)

What are the benefits for citizen and emergency services

The benefits of having a HTML5 Geolocation based solution is that it the technology are well tested and it is already in place in almost every Smartphone with GPS. With high penetration of Smartphone users and web browsers that support (>90%) this feature this is a viable solution to have available for emergency services.


Own the process and data

As an emergency service you have full control when and how to use it, since the process can be initiated and owned by the emergency service you always know what location data belongs to who. With user consent the location data can be exchanged directly between the smartphone and the emergency service without any involvement from the carriers. This makes it a global solution out of the box for the citizens.

When a successful location has been acquired, the accuracy it can be as low as 3 meters which makes a huge difference in terms of used resources and outcome of an emergency. In sparsly populated areas such as rural areas, mountains, woods, lakes and archipelago it can have an even greater impact compared to a network based solution using cellid which will most likely end up with a ~2km radius (refer to AML case study)

EENA AML case study

Examples of the use of HTML5 Geolocation

A list of success stories where HTML5 technology has been used can be long, but here are some examples of where it has made a difference in public safety.

Emergency services

  • A drifting boat with engine failure during harsh weather condition was successfully located and people where rescued. The rescue mission was successful due shortened lead-time to find the location of the incident which also leads to optimal use of resources.

  • A person who was lost in the woods could be guided back to the car only by giving instructions via phone. This was achieved by having the smartphone sending multiple locations points to determine current heading while walking.

Commercial use case

  • Google uses geolocation to determine your location to make your searches more relevant and contextual

  • H&M uses this technology in its core service design to easy find a retail store nearby

  • Twitter and Facebook also support this feature to match published content to a specific location

Try it yourself

Give your browser a spin on our test page


Johan Sandén

CTO & Co-Founder
Communications of CARL


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