How does Apple’s GPS report a location to 911

Having supported a 911 dispatch center in the past, I can tell you this is a difficult problem. Your location may be approximated based on your position between cellular towers. Depending on the agency, GPS may or may not be involved. A general statement would be if circumstances allow and a land line is available, use the land line to telephone 911 instead of a cellular telephone.

Like sberman, I also managed the changeover of our enhanced 9-1-1 dispatch center to begin accepting cellular 9-1-1 calls. The process is extreme, and it would depend on the phase of wireless call taking the dispatch center is currently using. Phase 1 just allows the calls to go to the dispatch center. Phase 2 provides the Caller ID information with the call, and Phase 3 gives them the approximate location of the caller, and each cellular carrier can have a different way to present that to the dispatch center. While all of this happens in the background, and the caller, and the dispatcher have no idea which method is used. It actually has nothing to do with the handset, they all can report the information to the cellular network, it is now the network compiles the information and reports it to the dispatch center.

I think it's a testament to how great these forums are that this question got such knowledgeable answers from you and sberman. Not only two answers to a relatively obscure question in less than 15 minutes (the first in less than five) but answers based on actual experience.

Are you then referring to using the Fall Detection feature for the Apple Watch? There is no feature for that on the iPhone. If you experience a detected fall and your iPhone is nearby, it will be used to contact emergency services for your location. If you are unable to speak, and your emergency services is configured for location services for 9-1-1, then they will be able to locate you from the phone. Being in a home, location data can be approximate, however when I look at Find My on my iPhone for my location, it is relatively spot on for my house. Worse I've seen is a few feet into my front yard. I think it would get emergency services there.

Thanks Idris. That was one of my greatest project experiences at the department while I was in a senior leadership position. That also really got me more interested in mobile communications and tracking. I appreciate your kind words, and the ability to add my experience to that of sberman's.

IdrisSeabright, I also appreciate your kind words and thoughts. I worked with the Los Angeles Police Department when they retired their vintage 1970s home-grown computer aided dispatch system for 911 calls and held a competition among off-the-shelf vendors to choose a commercially available system to replace it. Los Angeles had passed a bond measure to improve their 911 system and build two new dispatch centers. I was on this project for five years. I learned a lot about 911 and what's involved in dispatching, and I believe the LAPD learned a lot about computing, what's involved in maintaining software, writing requirements, the merits of deploying commercial versus home-grown software, etc.