911 Wireless Location Accuracy

BIG PICTURE
FindMeSAR is a backup option that a 911 dispatcher can consider using when other methods of locating a wireless caller fail.

LOCATING A WIRELESS CALLER
There are various ways that a 911 dispatcher can get the location for a wireless caller. The caller might provide a street address or the caller might describe landmarks they can see. Also in the USA any wireless carrier that handles a call to 911 is required to make "Phase 2" coordinates for the caller and an accuracy value available to the 911 dispatcher within 30 seconds. But note that there are large exemptions to that requirement.

PROBLEM
Some wireless callers to 911 cannot describe their location for various reasons. What if the carrier handling that call has exempted the call from the "Phase 2" location requirements? Or what if the carrier provides "Phase 2" coordinates but the accuracy value is 3,000 meters and the caller is on foot in the forest? Or what if the "Phase 2" coordinates are never available for some unexplained reason? Another source of problems are coordinates provided by the caller that turn out to be wrong by a mile or more.

SOLUTION

TIPS
To get the best GPS data, the user should be outside with a reasonable view of the sky or at least next to a window. Also, FindMeSAR is intended for cell phones and tablets. If you open FindMeSAR with a desktop or laptop browser then the results are unpredictable.

ELIMINATE USER ERROR
First, the FindMeSAR browser app does not display cached (i.e. old) coordinates. It only displays fresh coordinates. By reading the coordinate and accuracy value displayed on the screen there is no possibility that the caller will give 911 any kind of 'saved' coordinate or just a coordinate without also providing the equally important accuracy value.

Note! You should never use an app that displays coordinates but does not display the related accuracy value. After all, if the undisclosed accuracy value is 3,000 meters, then what good are the coordinates?

Second, FindMeSAR does *not* get just a single coordinate for the user. Instead, it gets a continuous stream of coordinate data. Usually the accuracy value will start out quite high but within 30 seconds will be under 10 meters.

During that process, FindMeSAR monitors the GPS datastream and displays appropriate messages if coordinates with good accuracy are not displayed in a reasonable time. For example, one message that might appear prompts Android users to change a setting on their phone in order to obtain much more accurate coordinates.

LOST PERSON SELF RESCUE
Sometimes a person who is lost can rescue themselves if they simply have a good map that shows their current location.

FindMeSAR includes a "Display map" button that will show the user's current location on a USA map. The map is displayed by GISsurfer which is a general purpose web map that is also produced by Mappingsupport. When the map opens a small red circle will follow the user and continue to show their position as the user travels. After the map opens the user can change the basemap if that would be useful.

In the USA and Canada the user can display a detailed topographic map by tapping the basemap button (next to the Menu button) and selecting "ESRI scanned topo USA" or "Canada Toporama".

Note! The GISsurfer map will only open if the cell phone is online.

For more information about the map please see the GISsurfer homepage.

YOU CAN TEST THE ACCURACY
Go outside and start FindMeSAR on your cell phone. After the accuracy drops to 10 meters or lower then you can check the location accuracy of the coordinates that are displayed by tapping the "Display map" button. After the map opens, tap the basemap button (next to the "Menu" button). Select the aerial "Esri aerial clarity". Check to see if the geolocation symbol does a reasonably good job of showing your location on the aerial.

WORKS OFFLINE!
The first time you open FindMeSAR a copy of this web app is automatically saved in a special part of your phone's memory called the application cache. This is *not* the same thing as the cache that your browser routinely uses. You can then open FindMeSAR when your phone or tablet is offline and it will work fine.

FindMeSAR also remembers which coordinate format you were looking at when you previously stopped using it. That same coordinate format will be displayed right away the next time you open this browser app.

You can add the FindMeSAR icon to your home screen and/or add a bookmark in your browser. Then to open this webpage when you are online or offline, simply tap the icon or bookmark.

If you open FindMeSAR when you are online then any updates are automatically saved on your phone.

iOS Safari users: To delete FindMeSAR from the Safari application cache do Settings ==> Safari ==> Advanced ==> Website data ==> Edit. Select findmesar.com. Delete.

Chrome for Android users: Below are some general instructions. If this does not work for you then try a google search: Chrome for Android clear application cache (your phone model).
Settings ==> Apps (or Applications) ==> FindMeSAR ==> Clear cache and app data.

WORKS WORLDWIDE
The FindMeSAR browser app can be used anywhere. If you know someone in a different country, invite them to give it a try. Remember, for the most accurate GPS coordinates the user needs to be outside with a reasonable view of the sky.

OPEN SOURCE JAVASCRIPT
FindMeSAR is open source written in a simple coding style using javascript. Any software developer can look at the code and confirm that nothing strange is going on.

Here is documentation for the
browser geolocation API.

OTHER FINDME BROWSER APPS
FindMePro is a research app that is intended to help the user discover how different settings on their cell phone affect the location accuracy of the coordinates that their phone produces. This is another public service project from MappingSuppport.

The following link starts FindMePro. For more information please see the "About" button.
Open FindMePro

ABOUT THE DEVELOPER
In early 2016 Joseph learned that all too often 911 call centers do not have accurate location coordinates for a caller that is using a cell phone. He then developed FindMeSAR as a public service anyone can use to provide a nearly foolproof way to give coordinates to 911 that have high location accuracy. This should help achieve the goal of less search and more rescue.

Joseph is also the developer of GISsurfer, PropertyLineMaps and various other projects related to online mapping. For information about these other projects and contact information please visit
https://mappingsupport.com.

DONATE
Donations are gratefully accepted.
Donate

DISCLAIMER
By using the FindMeSAR software you agree that you are doing so entirely at your own risk. You further agree that you will not make any kind of claim or file any lawsuit against the developer of this software.

PRIVACY POLICY
The FindMeSAR software does not retain your location data and does not share your location data with anyone.

Reminder: In the USA any wireless carrier that handles a call to 911 is required to make reasonably good coordinates for the caller available to the 911 dispatcher within 30 seconds. Often times this technology works fine. And often times a wireless caller to 911 can provide a street address or otherwise sufficiently describe their location. FindMeSAR is intended to be a backup option for when other location methods fail.

Voice and data at the same time

This part discusses whether a cell phone caller can talk to 911 and run FindMeSAR at the same time. In other words, can the caller do voice and data at the same time? There are several possibilities depending on the circumstances.

1. If a caller previously opened FindMeSAR on their phone then this browser app is already installed on their phone. The caller should be able to talk to 911 (or anyone else) and run the app at the same time. Since this browser app is already installed on the phone no internet data is required. The phone is simply making a voice call and running a browser app already installed on the phone. The issue of voice and data at the same time is not present.

2. The 911 dispatcher could ask the caller if there is a second cell phone available. If so, the second cell phone could browse to findmesar.com while the first cell phone continues the call with the 911 dispatcher.

3. 4G phones with VoLTE (Voice over LTE) technology typically can do voice and data at the same time. However, this might depend on the carrier than handles the wireless 911 call. Remember, all carriers are required to handle all 911 calls. Thus a Verizon phone that calls 911 might have that call handled by a tower for carrier xyz. Does that xyz tower have to have VoLTE technology in order for the caller to do voice and data at the same time? If anyone knows the answer (no guessing please) I would appreciate hearing from you.
Contact Joseph

4. If a caller (a) does not already have FindMeSAR on their cell phone, and (b) a second cell phone is not available and (c) the cell phone cannot do voice and data at the same time, then the 911 dispatcher will need to tell the caller to hang up, browse to findmesar.com, tap the “Next format” button to go to a certain colored screen, wait briefly for the accuracy value to get down to 10 meters or so and then call 911 back. Yes, dispatchers never want to stop a call. But doing so might be the only way to quickly get good quality coordinates for someone who needs help.

There is another issue related to situation #4. When a 911 call ends for any reason, then the caller’s phone is apparently ‘locked up’ for 5 minutes. Apparently the idea is to make it easy for the 911 dispatcher to call back. The user might be able to pull down a ‘notification’ screen and then cancel this 5 minute timer. Otherwise the user will have to wait 5 minutes before browsing to findmesar.com.