Finding your place

By Dominic Li, TruePosition

Dominic Li on the challenge of emergency communications in the mobile age.

“Currently, more than 70 percent of mobile phone calls take place indoors. By nature, mobile phones can be virtually anywhere, in any type of environment”
-Dominic Li

As mobile phones continue to grow as the dominant form of communication, the number of wireless calls to 911 has increased exponentially. A critical component of processing these wireless 911 calls is the ability to locate callers quickly and accurately. The debate continues as to which wireless location technology is best-suited for locating 911 callers. This debate is receiving global attention as nations around the world are looking to mimic the US Enhanced 911 (E911) system, and deploy their own emergency call location systems.

In order to be effective for E911, wireless location technology must meet several performance requirements - high accuracy, high reliability, ability to work with any phone, and ability to work in any environment. First responders need reliable access to accurate location data at the first request in order to find the person in need quickly. Furthermore, every wireless 911 call needs to be located regardless of the type or age of the mobile phone the caller is using or where that person is, including indoors, in cities, in vehicles - all places where many 911 calls originate.

The Global Positioning System (GPS) is decidedly the most widely known location technology, fuelled by consumer demand for location-based services like navigation and social networking. GPS relies on satellites to calculate the accurate location of a device or mobile phone.

In ideal scenarios, GPS locates mobile phones with very high accuracy - typically within 50 meters. It requires an open line of sight from the mobile phone to the satellites, and performs at its best in outdoor rural and suburban areas. Conversely, GPS performs inadequately or fails to work in environments where the line of sight is obstructed, such as indoors, in cities with tall buildings, and even sometimes inside of a vehicle.

Currently, more than 70 percent of mobile phone calls take place indoors. By nature, mobile phones can be virtually anywhere, in any type of environment. An E911 system that relies on GPS does not afford every caller the same opportunity to be located and rescued. Furthermore, callers whose phones are not equipped with a GPS chip will not be located at all.

A more suitable location technology for E911 is Uplink Time Difference of Arrival (U-TDOA). U-TDOA is a network-based technology that requires no additional upgrades to mobile phones. It relies on a technique that measures the time it takes the signal from the mobile phone to reach multiple location measurement units (LMUs) within the cell towers, and then uses the differences in those times to calculate an accurate location.

U-TDOA is uniquely suited for E911 because it is able to consistently locate any mobile phone, anytime, anywhere there is wireless connectivity, with a high level of accuracy (typically within 50 meters) and reliability. When a U-TDOA system is in place to locate wireless E911 calls, it does not matter where the person is calling from - at home, on a city street, or even lost in the woods. It also does not matter which type of phone the person is using, so regardless of the make or model of phone - GPS chip or not - if a person dials 911, emergency responders will be able to locate the victim quickly and accurately.

U-TDOA systems have been in place for E911 in the United States for the better part of the past decade, delivering accurate location information quickly to first responders for more than five million 911 calls every month. The U-TDOA system in the United States has produced many successes and the reason is clear: U-TDOA meets all of the requirements for mission-critical situations: it works with any phone, works in any environment, and it works very accurately and reliably. In short, it is the location technology that is ideally suited for emergency grade situations such as E911.

As Vice President of Marketing and Portfolio Management, Dominic Li oversees the development and execution of TruePosition's portfolio and marketing strategies, as well as the management of the corporate brand. Li brings more than a dozen years of experience in the telecommunications and technology fields. Prior to joining TruePosition, he managed the portfolio development, and marketing functions at Sprint Enterprise Mobility and was previously Vice President with British Telecom.