I just saw this YouTube video warning about the inaccuracy of cell-phones in relating their location to 9-11 dispatchers:

while it's true that modern cellphones can relay locations back to your 911 dispatcher, they are often too broad and can have emergency crew searching for minutes on end, wasting precious time"

Do cell-phones relay your position back to emergency services?

  • Is your question about the U.S. specifically?
    – Myridium
    Oct 24, 2016 at 6:06
  • No, it's not. I added this but it was removed.
    – UTF-8
    Oct 24, 2016 at 9:08
  • @Oddthinking's edit says "The claim was about the USA. Answers have already provided links that should satisfy your curiosity about other countries." - The claim in the linked video is indeed about the U.S., but it's not up to others to decide what question it is you're asking. Furthermore, the answers here say nothing at all about what happens outside the U.S.
    – Myridium
    Oct 24, 2016 at 9:13
  • I don't have the rep to rollback the edit, unfortunately.
    – Myridium
    Oct 24, 2016 at 9:15
  • @Myridium: I explained that the claim was about the USA. ("911 dispatcher" is a US term!) Questions that are not about a notable claim are off-topic.You are correct - the other questions don't directly mention other countries. I was thinking of the reference to the Wikipedia article that I read based on the link in Mark's answer, which covers other regions. [Please take care not to rollback edits on a whim. Edit wars aren't helpful.]
    – Oddthinking
    Oct 24, 2016 at 9:30

2 Answers 2


This is Enhanced 911 (easier-to-understand Wikipedia article): cell-phone network operators are required to transmit the location of a cellphone with a given level of accuracy to a 911 call center. It does not specifically require the use of GPS, but the accuracy requirements are such that GPS is generally used.

Excerpting the WIkipedia page:

The U.S. Federal Communications Commission (FCC) has several requirements applicable to wireless or mobile telephones:

[...] 95% of a network operator's in-service phones must be E911 compliant ("location capable") by December 31, 2005. (Numerous carriers missed this deadline, and were fined by the FCC.)

Wireless network operators must provide the latitude and longitude of callers within 300 meters, within six minutes of a request by a PSAP. [...]

In 1996, the U.S. Federal Communications Commission (FCC) issued an order requiring wireless carriers to determine and transmit the location of callers who dial 9-1-1. The FCC set up a phased program: Phase I involved sending the location of the receiving antenna for 9-1-1 calls, while Phase II sends the location of the calling telephone. Carriers were allowed to choose to implement 'handset based' location by Global Positioning System (GPS) or similar technology in each phone, or 'network based' location by means of triangulation between cell towers. The order set technical and accuracy requirements: carriers using 'handset based' technology must report handset location within 50 meters for 67% of calls, and within 150 meters for 90% of calls; carriers using 'network based' technology must report location within 100 meters for 67% of calls and 300 meters for 90% of calls.

  • Your answer covers less than 10% (just a rough Google estimate) of the human population with cell phones. The U.S. is not the only place with "emergency services" you know. What about elsewhere?
    – Myridium
    Oct 24, 2016 at 6:04
  • 3
    @Myridium, the question specifies 911 as the emergency number, and my answer covers at least 75% of the population who live in countries where 911 is the emergency number.
    – Mark
    Oct 24, 2016 at 18:21

Aside from GPS it is possible to deduce the approximate location of a cellphone by triangulation from the cell towers it is in contact with, indeed even knowing the location of the tower that received the call gives you some idea of the location. This, in itself is not very precise but for example in the case of a road accident may be enough as there are obviously a limited number of roads in a given area especially if you can say if you are on a major or minor road and give any landmarks, even saying I passed a town 10 miles back heading north will help.

also smartphones may use all sorts of other information to guess their location, especially if they are searching for WiFi connection as other devices witch have shared their location can be an indicator.

  • 2
    I know about triangulation. But the question is not about it. Is specifically is about the smartphone relaying its location to the emergency service. || Yes, smartphones have several ways of finding approximate locations. However, the question is not whether they have this information or can easily get it if asked to but whether they relay (and if necessary determine this information beforehand) it to the emergency service without the user telling the smartphone to do so (e.g. by copying the location an app got from the system's location service and sending a text message to the emer.service).
    – UTF-8
    Oct 20, 2016 at 22:23
  • 2
    While it's possible to triangulate a radio, you haven't shown any evidence that this does happen with cellphones, in relation to calling emergency services
    – Sklivvz
    Oct 21, 2016 at 0:04

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