Alerts & Notifications

Study Suggests New Approach for Targeting WEA Alerts

Johns Hopkins University says existing technologies that identify the location of a mobile device could be used to make delivery of Wireless Emergency Alerts more accurate.

by Rick Wimberly / November 15, 2015

Ability to geo-target alerts through Wireless Emergency Alerts (WEA) appears to have improved in the last couple of years, but the quest continues for more precision. Several vendors are offering solutions they think will help. Now, Johns Hopkins University is offering a path to improvement. Through a study commissioned by the Department of Homeland Security, the university’s Applied Physics Laboratory (JHU/APL) is suggesting a concept called Arbitrary-Size Location-Aware Targeting or ASLAT.  Hardly a snappy name, but an interesting concept.

Through ASLAT, alerts would be sent through the mobile device network, the same as WEA. But, unlike WEA, delivery of the alerts would be determined by a blend of geographic location capabilities being used for other purposes. WEA messages are currently delivered via a special broadcast signal from cell towers. If a device is within range of a designated tower, it should receive the alert. Success stories abound of lives saved by WEA using the current method, but some public safety practitioners have expressed concern that the method lacks adequate geographic precision.

In its report (found here), JHU/APL said “significant improvement in geotargeting accuracy can be achieved by ASLAT compared to current WEA geotargeting capabilities.” Simply put, alerts would be sent to a larger area than desired, but GPS (global positioning system) capabilities being used for other purposes would narrow delivery to only the desired area. These GPS capabilities include the ones you’re familiar with that help Siri and Google Maps give you driving directions.  

Converting from the current system to ASLAT would not be simple. First, cell carriers and their government partners (FEMA and FCC) would have to agree that benefits for conversion would outweigh the money and time spent to build a new system. The partners would also need to get comfortable with JHU/APL’s findings that ASLAT alerts would not eat up a lot of precious bandwidth or battery power. Plus, ASLAT alerts may not be quite as fast as current WEA alerts. According to JHU/APL, its approach would create a bit of latency as a device figures out whether the alert would should be delivered to the device. (For example, delays may make ASLAT unsuitable for earthquake alerts.)

On the other hand, JHU/APL says ASLAT could convey more information and give recipients an option to receive alerts in areas of interest outside their current location. That, plus better accuracy.

Whether the effort will be tackled is unseen. Public safety practitioners should speak up about whether the obstacles to implement are outweighed by the benefits of more precise delivery. Perhaps a forum will be provided to collect practitioner opinions. Maybe that forum would come from the advisory committee that a long-debated bill on the Integrated Public Alert and Warning System (IPAWS) would set up (assuming the bill is ever finally approved and signed into law.) Meantime, share your thoughts with us and we’ll try to get them to the right people.