Wireless Systems Design

E-911 Technology Serves 5 Million Calls A Month

Car crashes. Outdoor accidents. Street crime. Dangerous emergencies happen every day. Cell phones, though, enable quick response. Phase-II Enhanced-911 (E-911) technology required by the Federal Communications Commission makes it easy for EMS personnel to arrive on the scene when the caller is unsure of the precise location. In fact, technology from TruePosition Inc. locates an average of 5 million 911 callers per month—that’s 165,000 calls a day.

“TruePostion recognizes the importance of delivering fast, consistent, and accurate location information to emergency responders for all 911 calls and is proud to play a significant part in helping to save lives every day,” said Stephen Stuut, CEO of TruePosition.

The company’s uplink time difference of arrival (U-TDOA) technology is deployed nationwide in AT&T’s and T-Mobile’s networks as well as in geographies served by several Tier II and Tier III operators. U-TDOA triangulates caller locations via cell towers, comparing the times at which a cell signal reaches multiple location measurement units (LMUs) installed at the operator’s basestations. The network layout and deployment density of LMUs and base transceiver stations determines accuracy.

U-TDOA is based in the network, not on any additional chips or software. It encompasses indoor, in-vehicle, urban, suburban, and rural environments, challenged only in extreme rural conditions where cell sites are arranged in a “string of pearls” configuration. In such scenarios, angle-of-arrival (AOA) technology computes locations based on the signal’s angle of arrival at two basestations to supplement U-TDOA.

The FCC requires accuracy of 100 m for 67% of calls and 300 m for 95% of calls. According to TruePosition, its U-TDOA technology provides a yield of 98% or better and accuracy of less than 50 m. It determines location at the start of the call, mid-call, or when the phone is idle. It also locates voice calls and SMS messaging. And while that performance is impressive, the company is expanding its research, opening a new R&D center in Westborough, Mass., last month.

“We view Boston as an excellent area to establish our new R&D facility because of the current pool of high-tech talent and the positive entrepreneurial climate,” Stuut said. “We expect to further increase our presence in the high-tech community in the Boston area.” In fact, the 9000-square-foot facility will focus on the company’s next-generation Location Platform, incorporating hardware, software, and services for determining mobile-phone location.

TruePosition Inc.


TAGS: Mobile
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