Mountain Bike Reviews Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter · #1 ·
I am a software developer working with online maps and location technology. Earlier this year I became interested in what happens when someone with a cell phone calls 911. In particular I wanted to know the details of how the 911 dispatcher learns the *location* of the caller. What kind of digital magic happens behind the scenes?

Much of what I learned came from reviewing documents on the FCC’s website. On one hand I learned that the FCC requires a wireless carrier handling a 911 call to produce coordinates for the caller’s location. Sounds good, right? On the other hand I learned that many carriers have exempted themselves from this requirement over large portions of the area they serve. I also learned that the coordinate accuracy most of us easily get on our smartphones (or handheld GPS) is often 10 times more accurate - or more - than the coordinates produced by the wireless carrier handling a 911 call.

Recently I finished a report that shares what I learned. That report consists of:
1. A list of tips for calling 911 with a cell phone.
2. Background information so you understand the big picture.
3. Detailed information to support each tip.
For those wishing to dig into the source material for themselves, the report includes links to various documents on the FCC website.

I posted a copy of this report on my server at
https://mappingsupport.com/p/sar/call-911-with-a-cell-phone.pdf

Here are the tips. I am happy to answer questions.

--- Tip #1 ---
If you need to call 911 and your cell phone shows ‘no service’, then you should call 911 anyway and let it ring 45-60 seconds before hanging up.

--- Tip #2 ---
You should give the 911 dispatcher your location by providing (1) a street address, or (2) a verbal description the dispatcher understands, or (3) your latitude longitude coordinates expressed as decimal degrees.

--- Tip #3 ---
FindMeSAR is a browser app that was developed as a public service specifically to provide an easy and ‘no cost’ way for anyone with a smartphone to display their coordinates and accuracy value while their phone is either online or offline. This is not a commercial product of any kind. It is a volunteer project just to try and help people when they need help.

--- Tip #4 ---
When you call 911 with a cell phone the wireless carrier handling the call might not produce *any* coordinates for your location.

--- Tip #5 ---
Even if the wireless carrier handling your 911 call does produce coordinates for your location, the coordinates you can obtain from your smartphone are either (1) more accurate or (2) a lot more accurate than the coordinates produced by the wireless carrier.

--- Tip #6 ---
If (1) your phone is not within range of a cell tower and (2) your phone does not have a current copy of the satellite ‘assistance’ data, then it will take 15 to 20 minutes before your phone will produce coordinates for your location.

--- Tip #7 ---
No one is monitoring the wireless carriers to see whether or not they are in compliance with the standards and requirements that the FCC has adopted regarding wireless calls to 911 and coordinate data for the caller’s location.

--- Tip #8 ---
If you have an android phone then to get the most accurate coordinates set the location mode (or method) to “GPS only”.

--- Tip #9 ---
If you have an Android phone then there is a free and easy way to find out if your phone can produce more accurate coordinates by using data from both the USA satellites (GPS) and the Russian satellites (GLONASS).

--- Tip #10 ---
Phones that have no service plan at all can still (1) call 911 and (2) run an app that displays coordinates and accuracy on the phone’s screen.

--- Tip #11 ---
If at all possible, make a voice call to 911 instead of texting.

--- Tip #12 ---
If you do text to 911, then the dispatcher is most likely not going to have *any* location data for you unless you include it in your text.

--- Tip #13 ---
After you contact 911 take steps to make your phone’s battery last as long as possible.

Joseph
 

·
Registered
Joined
·
9,742 Posts
In google maps on Android you can touch and hold a spot and the coords will appear in a search box at the top. You can copy and paste them: Tap the coords, then touch and hold to select, extend selection appropriately, copy...
 

·
Cycologist
Joined
·
7,585 Posts
--- Tip #3 ---
FindMeSAR is a browser app that was developed as a public service specifically to provide an easy and ‘no cost’ way for anyone with a smartphone to display their coordinates and accuracy value while their phone is either online or offline. This is not a commercial product of any kind. It is a volunteer project just to try and help people when they need help.

Joseph
bookmarked, thanks
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #7 ·
Thank you for the kind words.

Here is a followup idea to help find people that have called 911 and are not able to give a street address or adequately describe their location.

As explained in the report I posted, when someone with a cell phone calls 911 the wireless carrier is supposed to make reasonably good coordinates available to the dispatcher. Often times that system works fine. But also many times this system does not work well and either the wireless carrier never produces “phase 2” coordinates or do so but the accuracy of the coordinates is terrible.

There are 6,000+ 911 call centers in the USA. These are known as PSAPs (Public Safety Answering Point. The problem of wireless carriers not providing accurate coordinates for wireless callers is going to vary from one PSAP to the next.

Now here is the idea. When a 911 dispatcher has a problem getting an accurate location for a wireless caller, the dispatcher can ask the caller to:
1. Browse to findmesar.com
2. Tap the "Next format" button until the yellow screen appears. This screen shows the caller's location in decimal degrees which is the same format the wireless carriers use to send location data to 911 call centers.
3. Wait a few seconds for the accuracy to get to 30 meters or smaller.
4. Tap "Stop"
5. Read off the coordinates, accuracy, timestamp and (optionally) elevation.

No, this will not work in every case. FindMeSAR does not work on flip phones. And the first time someone tries to use this app their browser has to be online. Unless the phone is on wi-fi, this means the phone has to have a data plan.

Yes, FindMeSAR will work in many cases and the person who called 911 for help will be able to very quickly read accurate coordinates to the dispatcher. Here is a short report from a SAR team in New Mexico that used FindMeSAR to locate lost hikers. The story seems to indicate that “phase 2” coordinates from the wireless carrier were also available but they were not accurate. Atalaya Search and Rescue

Also FindMeSAR has been reviewed and added to the APCO app page at AppComm. APCO is an international organization for public safety communication professionals.

If you know someone who works in public safety (dispatcher, police, fire fighter, SAR, etc) please consider asking them to take a look at this idea of your local PSAP using FindMeSAR as a backup plan to help locate wireless callers.

Finally, I will point out again that FindMeSAR is not any kind of commercial product. Over the years I have traveled in the backcountry a fair bit on foot, skis and horseback. Fortunately I have never needed to call for help but I know people that have not been as lucky. This volunteer project is part of my way to 'pay it forward' and also show appreciation for all those involved in SAR and other emergency response.

Joseph
 

·
Rent this space for $
Joined
·
3,641 Posts
Interesting info, thanks.

I've wondered about utilizing 911 through texting. Is this actually a viable means of contact for most systems? I get that location services would be non-existent but do all 911 centers have the capability to field messages sent through text? I've never seen this brought up before.

Also, more specifically for mountain bikers, the free Pinkbike.com created "Trailforks App" for which I am a regional administrator, is a user generated trail mapping system where you download specific regions of maps to your phone thus allowing you realtime GPS location services as you ride the trail regardless of cell service availability. Obviously you would need service for the Emergency feature to make contact but with the touch of a button on the app, you are immediately on a page with your Lat/Lon coordinates and a button that will dial 911 when touched.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #9 ·
At the present time most 911 call centers (PSAPs) can *not* receive texts. Slowly that will change.

Even PSAPs that can receive texts always want you to make a voice call if possible. There are a bunch of good reasons for this. Dispatcher can get more info more quickly. Wireless carrier might produce accurate coordinates. Cell towers will make data records that can be mined by experts to narrow a search area.

If the "Trailforks App" does not already include the coordinate accuracy value on its 'panic' page, then I highly recommend that feature be added. SAR teams might tend to be skeptical of user-supplied coordinates that do not include the accuracy value.
 

·
Rent this space for $
Joined
·
3,641 Posts
Thanks for the text info.

EPE is included.

The first pic is selecting the menu while on a map page.

Screenshot_20161230-094356[1].jpg

This is after selecting the "Emergency" button.

Screenshot_20161230-094410[1].jpg
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #11 ·
I respectfully suggest the accuracy value in that app be in the same font as the coordinates. That will make it much easier to read in poor light and/or with bad eyesight.
 

·
Registered
Joined
·
9,742 Posts
^^^hardly any trails in my area in that app. OSMs shows zobs more, almost all of them. Can you not use OSM for the mapping?

And, it shows my current position correctly but says it's "near" a point that's about 5 miles away.
 

·
Rent this space for $
Joined
·
3,641 Posts
^^^hardly any trails in my area in that app. OSMs shows zobs more, almost all of them. Can you not use OSM for the mapping?

And, it shows my current position correctly but says it's "near" a point that's about 5 miles away.
For clarification, which app are you referring?
 

·
Registered
Joined
·
11,036 Posts
This is great information that everyone should know. I'm in the UK though so I'll need to try and find out what the situation is over here.

There was a very sad case in Edinburgh about five years ago. A young girl was walking home along the canal path and realised she was being followed. She made several calls to the police asking for help. Although the calls were recorded, they were not put through to the police. She was raped and murdered in the city centre, just yards from busy streets, because her mobile provider did not put her 999 calls through.
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #15 ·
This is great information that everyone should know. I'm in the UK though so I'll need to try and find out what the situation is over here
In the UK when someone uses an Android phone to call 999 some wireless carriers (most carriers?) make use of Google's "Emergency Location Service". This service is already built-in to Andoid.

This "Emergency Location Service" gets coordinates from the caller's phone and sends those coordinates to the 999 call taker. These coordinates come from the phone's location services and are the same coordinates the phone routinely uses for location-aware apps.

In the USA, the Federal Communication Commission (FCC) prohibits the use of the highly accurate coordinates that can automatically be obtained by Android's "Emergency Location Service" for the reason that most phones produce coordinates by using data from both USA satellites (GPS) and Russian satellites (GLONASS). More satellites = more data = better accuracy.

Instead, in the USA wireless carriers attempt to produce less accurate coordinates for the 911 wireless caller by using (1) just the USA satellites or (2) cell tower triangulation.

This is one of the main reasons why I recommend that everyone have an app (FindMeSAR or some other app) on their phone that can display their coordinates and accuracy value. In the USA, coordinates provided by a wireless caller are almost always going to be either more accurate or a lot more accurate than coordinates provided by the wireless carrier.

To read more about this along with some links, please see p.4 of the report I posted. A link to the report is in the first post of this thread.
 

·
Registered
Joined
·
9,742 Posts
A bit OT for this threads, but OSM has virtually all the trails around me far and wide. Why not use that for the base map instead of Goggle maps or whatever they're using?
 

·
Rent this space for $
Joined
·
3,641 Posts
It's not cookie cutter and clutter. They're building a user sourced system of mountain bike trails across the world that allows someone from out of an area to go to that area and by downloading a large region, that person can access any and all the ridable trails and related information. We users can then go and offer reports on trail conditions as we experience them and trail builders/organizations can actually track and schedule maintenance on said trails.
 

·
Registered
Joined
·
9,742 Posts
That's all good, but use a base map that actually shows trails. Do all that other good stuff on top of that. IMO. Around here, Trailfoks doesn't show a hundredth, maybe not a thousandth of the rideable trails.

The "near: info on the emergency info page isn't much use in an emergency if it doesn't call out something closer than 5 miles. Also, it might be helpful if the lat and long could be cut and pasted, say into a text.
 
1 - 20 of 20 Posts
Top