Nov 18, 2013 at 9:27 am #1309956
USA cell phone callers expect that when we call 911 for an emergency, first responders can find us, even if we can't tell them where we are.
Don't count on it.
For example, 911 call centers receive accurate locations for only 19% of California 911 calls made from T-Mobile cell phones.
The causes are complex, and solutions are expensive. Below I provide a simplified explanation.
Bottom line: Today, your 911 call probably will not include an accurate location. And this problem won't be fixed soon.
The FCC requires cell phone companies to provide 911 call centers with caller locations accurate to 50 to 300 meters ("Phase II locations") – outdoors – unless you are in certain counties chosen by the cell phone companies.
Several technologies can provide sufficiently accurate locations, including GPS built into the phone, cell tower triangulation, and a few complex methods using cell towers or TV stations.
If the cell phone company can't provide an accurate location, they provide a "Phase I" location, i.e. the location of the cell tower handling your call. Since some cell towers cover over 100 square miles, these locations are not very useful for 911 call centers.
In order to provide accurate 911 call locations, most cell phone systems require cell phones to send GPS locations, so every new cell phone includes a GPS receiver.
Since 2008, the percentage of cell phone 911 calls with accurate locations has dropped or barely changed for most cell phone systems. Here's a chart from five areas in California; similar problems have been reported in other states.
In particular, accurate locations for calls from AT&T and T-Mobile phones have dropped significantly and continue to decline. Only Verizon provides accurate locations for just over half of 911 calls; other companies are worse.
The causes are complex, and each side in the argument makes certain claims and refutes claims from the other side.
In brief, some causes might be:
– Over-reliance on GPS. GPS positions are not available inside buildings (where an increasing percentage of 911 calls are made), and 911 positions are not immediately available to 911 call centers (due to the time required to generate a GPS position).
– 911 call centers don't "re-bid" (ask again 30 seconds later) for location information. Cell phone companies claim that 99% of 911 calls contain accurate information, eventually. However, many 911 calls don't last long enough for a re-bid, and some 911 call centers can't or won't re-bid.
– The FCC permits cell phone companies to exclude counties, or portions of counties, only where wireless carriers determine that providing location accuracy is limited, or technologically impossible, because of either heavy forestation or the inability to triangulate a caller's location. After 30 minutes of digging, I could not find those reports for Verizon, AT&T, or Sprint; I've linked to T-Mobile's exclusion report below.
Today, November 18, 2013, the FCC, 911 call center representatives, and cell phone company representatives are in a workshop to try to fix the problem. Expect a lot of finger-pointing and no real solutions, since probably everybody involved needs to spend more money to solve the problem: adding better location technologies, upgrading 911 call centers, etc.
Today, your 911 call probably will not include an accurate location. And this problem won't be fixed soon.
FCC 911 Wireless Services
FCC Workshop On E911 Phase II Location Accuracy, November 18, 2013
Wikipedia has a good overview of different 911 location technologies:
News reports on 911 location problems:
AT&T's public response to these problems:
T-Mobile list of excluded counties:
http://apps.fcc.gov/ecfs/document/view?id=7021747627Nov 18, 2013 at 9:50 am #2045799
@hknewmanLocale: Western US
After finishing a Point Reyes backpack in late 2010, I turned on my cell phone driving towards Fairfax CA and was shocked with a "no service" in the northern part of the Bay Area. Maybe coverage has improved since then, maybe not.
During my most recent overnight, a traditional pack weight buddy had a newer iPad (none retinal display) with a Trimble brand GPS/map program. Though we were out of cell phone range, the iPad GPS was fairly accurate (refracting a bit when we were under tree cover as GPS are apt to do regardless).
The key thing is we were out of cell phone range, so any 911 call regardless would have involved a runner descending a couple miles of frozen sleet, maybe more … trying to get cell phone service to tell the operator we were at a known point (the San Mateo Lookout). Also we all had iPhones w/ different providers … ATT, Verizon, etc.. with no bars in the true wilderness. One of those risks everyone undertakes voluntarily….Nov 18, 2013 at 10:12 am #2045806
Good article, Rex.
–B.G.–Nov 18, 2013 at 12:45 pm #2045866
John S.BPL Member
Good Morning America talked about this today. They said gps doesn't work good enough for location inside a building or even inside a car.Nov 18, 2013 at 1:35 pm #2045887
I wonder what happened to self-reliant wilderness travel? Has it been subsumed (or utterly displaced) by the cradle-to-grave nanny state?
For the record, we do not carry a GPS, a PLB, a SPOT or any mobile phone. We do carry a topo map and a compass – and we rely on them and ourselves. Just like all walkers of previous generations.
CheersNov 18, 2013 at 1:37 pm #2045888
"They said gps doesn't work good enough for location inside a building or even inside a car."
That is fairly accurate, but there are some gray areas. I spent many years helping customers with permanent GPS installations, so I know.
Most buildings have enough metallic 'crap' in the attic or on the roof that it blocks the signals. A case in point is that much fiberglass attic insulation is backed with aluminum foil. A few buildings are constructed with thin, modern materials that are transparent to the signals. Some buildings have a central atrium with a transparent skylight, so you can get a GPS fix in the center, but not so much toward the outside. Some residences are constructed out of stucco, but that is formed over a metallic mesh, so it blocks signals. GPS can sneak in through a wide window, but that is very unpredictable. In a TEMPEST-rated building, you will get zero signal inside. I've seen people try to install a GPS antenna inside a TEMPEST building, and they will pull out their hair trying. Don't ask me how I know this.
Cars are unpredictable as well, due to the shape. Some cars have a mostly vertical windshield, and others have a very windswept windshield. If you can get the GPS antenna far enough forward underneath the windshield that it can look up and see most of the sky, then that mostly works. But, if it looks up and sees mostly the metal roof of the car, then that doesn't work. Additionally, the GPS view out the side windows is very unpredictable. A few cars have a metallic glazing on the windshield glass, and I think that is a electrical conductor for windshield defrosting and deicing. That metal also tends to block the GPS signal. In contrast, if you can get an external GPS antenna outside the metal chassis of the car, then that tends to work good. Some newer cars have a bunch of cell phone and GPS navigation electronics in them. Most of the time, they put the GPS antenna either outside next to the rear window, or else inside on the rear window package shelf (where it can get a good view straight up). Some cars have an OnTrac system, and it generally puts the GPS antenna back there near the rear window, but it puts the control head in the inside rear view mirror.
So, there are no absolute rules for any of this. You need to stick a handheld GPS receiver in the building or car and test it.
–B.G.–Nov 18, 2013 at 1:43 pm #2045892
"I wonder what happened to self-reliant wilderness travel?"
You underestimate the power of a modern marketing department. They do not need to prove the effectiveness of GPS, a PLB, a SPOT, or any mobile phone. All they have to do is to advertise a solution, whether the problem really exists or not. Then they let the world beat a pathway to their door.
Mark me as a cynic.
On the other hand, Roger, some day you will arrive at a certain age when your body isn't as reliable as it used to be. You will be in the outback when your knee buckles and you are incapacitated. Without any means of calling for emergency help, the drop bears may get you.
–B.G.–Nov 18, 2013 at 3:01 pm #2045922
The best answer is "all of the above." Get a decent GPS/cellphone, but don't forget the map and compass, and the basics of the ten (or is it fourteen or so?) essentials. Get first aid training, carry basic stuff, and stay current. Get your bod in decent shape, etc.etc.
The PLB people have got to be grateful for wives and relatives who press for the purchase and use of their devices. It is clear that they can make a difference in some cases, but they are ideally an addition to the basics that have operated for centuries. I wonder if there are any objective studies that indicate to what extend the PLB gadgets have actually improved the situation?Nov 18, 2013 at 3:17 pm #2045929
@drusillaLocale: Wild Wild West
Well, it's kind of easy to look the stats up. Thousands of lives have been saved with PLB use. Both of my Fathers use them religiously as one flies a plane and the other is a lifetime man of the sea on ships and boats fishing and traveling and neither of them would go out without the PLB's they use. I spent 48 hours stalled in high seas once in some very rough weather and we still did not call for help as we felt we could fix the engines that failed and eventually did. When I started traveling on foot and over landing in remote areas my fathers insisted that I carry a PLB, I use an ACR, and yep it's a pain to carry, expensive to buy and I consider it a "luxury item" but it gives both my family and myself some peace of mind. I am considering switching to a smaller ACR soon.Nov 18, 2013 at 3:30 pm #2045936
"For the record, we do not carry a GPS, a PLB, a SPOT or any mobile phone. We do carry a topo map and a compass – and we rely on them and ourselves. Just like all walkers of previous generations."
With you most of the way here. I carried nothing but a map and compass until I was in my early 60's, at which point I finally caved and started carrying a PLB, primarily for my wife's peace of mind. That said, I suspect I will go to my grave without using either a GPS or a sat phone. My one temptation is an altimeter for use up here in the Cascades, where we get a lot of whiteouts. Been thinking on it for years now, and still haven't got one…..Nov 18, 2013 at 4:02 pm #2045946
Stephen BarberBPL Member
"I carried nothing but a map and compass until I was in my early 60's, at which point I finally caved and started carrying a PLB, primarily for my wife's peace of mind."
Ditto. And in southern California mountains, just about any time of year, if I break a leg or whatever, I think a smokey fire will get attention and help faster than my PLB.Nov 18, 2013 at 4:17 pm #2045953
"My one temptation is an altimeter for use up here in the Cascades, where we get a lot of whiteouts."
But even if you have an altimeter, when you get in a whiteout you are still in a whiteout. The altimeter can tell you approximately where you are on the slope, but you still have to use your topo map to figure out the route.
In contrast, if you use a GPS receiver, you can lay a path of "electronic breadcrumbs" from the trailhead all the way up a peak. Then, if something like a whiteout happens and you are forced to retreat, all you have to do is to follow the breadcrumbs in the track log right back in the reverse direction, and you don't need the other items so much unless you burn your GPS battery up or the satellites fall out of the sky. Besides, if you like the barometric altimeter function, some GPS receivers have that built-in. Otherwise, you can deal with the "GPS altimeter" which is not perfect.
Personally, if I get into a whiteout, I lose all instinctive sense of direction.
–B.G.–Nov 18, 2013 at 7:47 pm #2046031
> an altimeter for use up here in the Cascades, where we get a lot of whiteouts
Buy one! A serious aid to navigation, on a par with a compass in the mountains. Mine is in my watch.
CheersNov 18, 2013 at 9:35 pm #2046061
I'm not encouraging anyone to take a cell phone, inReach SE, PLB, or even a map and compass (*) into the wilderness. That's an individual decision, and I respect whatever decision you carefully consider. Especially if you have all the facts.
Which is one of the reasons I started this thread. Many people believe cell phones work everywhere, and that a call to 911 will result in a helicopter dropping from the sky in a few minutes. Reality is quite different, and I was shocked at how bad 911 call location delivery has become. Especially troubling is the contrast between the sharp drop for AT&T, versus gradual improvement for Verizon. Important parts of the story are still missing.
So, given that you have a cell phone, and call 911, what can you do to improve your chances of being found and helped?
– Be prepared to tell 911 operators your location to the best of your ability.
– Make your call from an open area with a good view of most of the sky. Give GPS a chance!
– Stay on the line with 911 until they hang up. Longer calls are more likely to to get located properly.
– Still lost? Ask the 911 operator to run a "re-bid" after a couple of minutes on the call. It's worth a try.
(*) Humans tramped in the wilderness for hundreds of thousands of years, eventually populating most of the world, without a map and compass. Many people still do.Nov 18, 2013 at 9:53 pm #2046067
Here's the Good Morning America clip on 911 location problems that John mentioned:
Light on details, long on consequences.
— RexNov 18, 2013 at 9:56 pm #2046068
"Especially troubling is the contrast between the sharp drop for AT&T, versus gradual improvement for Verizon."
Rex, I can't give you an instant answer. Some of the large cellular companies are known for "rolling their own networks" with their own staff, and they have only themselves to kick around if it doesn't work right. Other large cellular companies are known for "farming it out" to small contractors who may be unlikely to use all of the most sophisticated pieces and parts to get it done. So, there can be a big difference in the service you get in one place versus another place. As I stated previously, carrying the traffic is where they make the bucks, so their investments often track that, and taking care of the unfunded mandates from the FCC often slides around on the "to do" list.
In early June, I was in a large national park trying to make a cell phone call, and it would never go through (service unavailable). Everybody else with a different service provider was making their calls OK. As soon as I left the park, mine worked. Go figure.
–B.G.–Nov 19, 2013 at 2:00 pm #2046241
> – Be prepared to tell 911 operators your location to the best of your ability.
Sadly, that may not work.
We had a case here in Australia not too long ago when a kid fell, was injured, and tried to call for help. He was on the side of a 'mountain' in the middle of the bush. The operator kept asking him for the nearest cross-roads and simply would not accept that there were no roads anywhere nearby. The battery ran out and the kid died.
SighNov 20, 2013 at 1:11 am #2046418
eric chanBPL Member
a rescue today around vancouver thats very relevant to cell phone location accuracy …
i started a thread about it in general …Nov 20, 2013 at 4:35 pm #2046649
"But even if you have an altimeter, when you get in a whiteout you are still in a whiteout. The altimeter can tell you approximately where you are on the slope, but you still have to use your topo map to figure out the route."
I had assumed folks would understand that a topo map and compass would already be in use. Apparently I was wrong. ;0)
So far I haven't felt the need for a GPS unit, convenient as it may be until the batteries go(not unheard of when you are laying down a continuous trail of bread crumbs, I'm told), you're in heavy forest(not unknown up here in the Cascades), or you drop it at an inconvenient spot. Something about teaching an old dogs new tricks? Especially when the old ones have worked well enough for 40 some years and counting.Nov 21, 2013 at 4:51 am #2046802
wiiawiwb wiiawiwbBPL Member
I'll begin by saying that I am worried to death about the current crop of young cell-phone users. They have an attachment to their cell phones akin to newly-born babies attached to their mothers. Virtually inseparable. On the trail, their cell phones are out and they are talking, texting or taking pictures.
I am highly confident that these techies believe their phones will rescue them the same way Tooter Turtle was saved every time by Mr. Wizard. Drizzle, drazzle, drozzle, drome; time for this to come home. Poof, they're back in their warm and cozy living room. All is well. Only a noddypeak believes that.
Many inexperienced hikers bring only their cell phone and have no compass or understand how to use one in conjunction with a map. I belong to a SAR group and it's head shaking how many people haven't even a rudimentary grasp of wilderness navigation. Needless to say they also don't know a thing about wilderness survival other than what they saw Bear Grylls do.
Those folks need to learn how to use a map and compass and practice it. They shouldn't put themselves in a position where they need to be extracted. Granted, things outside your control can go wrong. An animal attack, a heart attack, a broken leg or ankle. Having a PLB, rather than a cell phone, will bail you out. I call that smart.
I don't see anything wrong with taking advantage of technology. If you take a winter tent into the back country, you are relying on modern technology. If you wear the latest and greatest materials, you are relying on modern technology. That's not a bad thing.
What is bad, is not knowing what to do if technology fails you.Nov 21, 2013 at 3:25 pm #2046986
"Buy one! A serious aid to navigation, on a par with a compass in the mountains. Mine is in my watch."
You knocked me off the fence. Sigh…another piece of gear, albeit not very shiny
and won't be gathering dust in the closet. Do you have any recommendations for a reliable device?Nov 21, 2013 at 10:23 pm #2047088
Before we went walking in Europe I never bothered with a altimeter. Around the Blue Mts we were either on the plateau or in a canyon – and we did not need an altimeter to tell the difference!
But in the European Alps – a very different story. I used the altimeter more often than the compass – both in conjunction with a topo map of course. 'I am at 1627 m, so I am here on this spur.'
What sort? Ah well, that's where personal preference strikes. Small rant: the marketing guys seem to think if a watch has an altimeter in it its must also have a compass – and the compass components are super bulky. Add to which the in-watch compasses are extremely unreliable: tilt one and North moves 10 – 20 degrees. Yes, I have MEASURED that. In fact, my testing of one watch at BGT resulted in the watch being withdrawn for 3 months and re-engineered!
What I would like is a small watch with altimeter (and therefore barometer) and virtually nothing else. OK, Dual time is useful: Time2 is set to European time, while Time1 is set to Australian. However, the marketing guys seem convinced that they MUST load the watch up with (mostly useless) features and make it big enough to use as a tent stake hammer. Something to do with the machismo of having 1 kg of plastic electronics on your wrist. Oh yes, I had better add: the watch bands are mostly built like Hummers. Severely irritating.
So I cut the watch bband off (or pop the pins and remove it), and hang the watch around my neck beside or in place of my compass.
What brand or model? I dunno – they change every year. As small and as cheap as you can get.
So I wandered around in eBay to see what's available. Search string "+watch +altimeter" and sort on price. Oohhh – new models which would suit me fine! While we do not like eBay URLS for listings, just pointing out what is available is OK once or twice. Try http://www.ebay.com.au/itm/Outdoor-Digital-Altimeter-Compass-Barometer-6-in-1-Thermometer-Weather-Watch-LCD-/171124508614?pt=AU_Gadgets&hash=item27d7d0c7c6 for instance ($10), but that unit is available from many vendors. Pick one which looks honest (ROTFLMAO). The Fishing unit ($20?) also looks interesting – with mini-carabiner even! Neither of these are wristband watches – good.
Or you can pay $300+ for a Rolex or whatever…
CheersNov 22, 2013 at 6:55 am #2047116
Andy FBPL Member
"I'll begin by saying that I am worried to death about the current crop of young cell-phone users. They have an attachment to their cell phones akin to newly-born babies attached to their mothers. Virtually inseparable. On the trail, their cell phones are out and they are talking, texting or taking pictures."
We are the Borg. Lower your shields and surrender your ships. We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile.Nov 22, 2013 at 3:56 pm #2047258
"So I wandered around in eBay to see what's available. Search string "+watch +altimeter" and sort on price. Oohhh – new models which would suit me fine! While we do not like eBay URLS for listings, just pointing out what is available is OK once or twice"
Many thanks for pointing me in the right direction. That piece gives me a pretty good idea of the parameters involved. Like yourself, I'm not particularly enamored
of eBay, not that the rest of the cyber world is awash in honest sellers, nor do I much care for bells and whistles. So, it is nice to know that there is at least one relatively simple unit on offer. If I don't find something else a little closer to home, I may just return and gamble $10 on the eBay trinket. Worse come to worst, I can put Paypal's dispute resolution pledge to the test. ;-]
Edited: $300 isn't gonna happen.Nov 22, 2013 at 6:25 pm #2047291
Eric BlumensaadtBPL Member
@danepackerLocale: Mojave Desert
Over Thanksgiving I'll see my son-in-law, Dr. Douglas Sicker, who was the Chief Technologist for both the FCC and the Commerce Dep't. in 2011 & 2012 respectively.
If anyone (that I know) has an answer he would
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