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New app developed to locate people in areas with no phone signal
Researchers of the Universidad de Alicante (UA) have developed new technology that makes it possible to locate people who have suffered an accident in remote locations without a phone signal and where a speedy rescue is essential to save lives. The system can also be used in emergency situations that arise as a result of earthquakes, floods or forest fires, where mobile phone infrastructure is often rendered useless.
"We have designed an application (app) that can be incorporated to any Smartphone and that, without a signal, emits a Wifi signal which in turn acts as a distress beacon over a distance of several kilometers", explains the creator of the technology and professor at the UA's Department of Physics, Systems Engineering and Theory of the Signal of the Higher Polytechnic School, José Ángel Berná. This signal contains the location (coordinates) of the person who has suffered the accident or disappeared and is using the Smartphone emitter, along with a short message that "can be altered depending on the situation, with examples such as 'I am injured', 'I am disorientated' or 'I need help'", specifies Berná.
In order to detect the distress signal, the researcher has also created a light (half a kilo), portable receptor device which rescue teams or mountain shelters could use. This device has a small antenna and connects to the Smartphone of the search party. When an accident occurs, the victim only has to activate the mobile phone app, which will in turn emit the distress signal periodically – for hours or even days, even if he or she is unconscious – indicating the coordinates of its location.
The Network of Valencian Universities for the promotion of Research, Development and Innovation, RUVID, is a non-profit private organisation that was born in December 2001 through a partnership agreement between the five public universities from the Valencian Region.
(Score: 3, Interesting) by Knowledge Troll on Friday December 29 2017, @03:25PM (10 children)
First of all I think everyone is familiar with the fact that WiFi signals simply don't travel very far. This is because it is always on 2.4ghz or 5.8ghz with power levels of a few hundred milliwatts and the nature of microwave RF communication. You can do things to make this communication distance longer such as using a directional antenna but there is no evidence I saw of that and in fact the statement that the receiving device has a "small antenna" would indicate in fact it is omni directional. Possibly they are using a more sensitive receiver than a typical WiFi router but considering the cost of the device at $600 I doubt it is anything exotic.
This means being able to receive the signal is going to require line of site to the transmitter with the small exception that the signal may possibly make it out of a structure but if that is true it won't be received at the full distance of a few kilometers. What won't happen is receiving anything if there is something like a hill between the receiver and the transmitter.
But wait! The search and rescue team could just go up to high spots, such as the top of the hills or mountains, and get line of site to a large area. This is true and it would work even better if a helicopter was used as then massive amounts of area could be scanned. Ah but the article mentions specifically this is supposed to be used instead of helicopters so tops of hills it is despite the fact that a few hours of helicopter time at a couple hundred dollars per hour most likely costs less than all the time investment from all the staff or volunteers doing a more intensive search. Ho hum.
So what we have here is a system that realistically could help search and rescue teams find a missing person when the phone is transmitting but what it won't do is help them identify when a person has gone missing or needs emergency assistance because they must already be looking for this person because of the limitations of the signal. This is actually significant because there must exist a time period when the system is transmitting the beacon signal and when the search and rescue team is looking for it.
When a person goes missing there is not usually an immediate response because someone has to realize they are missing first. This can cause many days of delay before a search party is formed. Presumably the person who is lost or injured or otherwise needs immediate help has activated the transmitter as soon as they realize it which will be ahead of when anyone is looking for them. Most smart phones can't run for many days even when they aren't constantly transmitting a WiFi signal at full power.
It gets even worse though - I checked my cell phone battery (it's a Samsung Galaxy series I actually do achieve about 4 days between charges with my usage patterns, which don't include WiFi use on the phone) and it is rated at 10.7 watt-hours but lets just call it 11. Remember that several hundred milliwatts power output for the WiFi signal from the phone? In an ideal theoretical sense the absolute maximum transmit time for the WiFi hardware alone (not including any other power usage on the phone at all) would be around 44 hours assuming 250 milliwatts output. The radio won't run with full duty cycle but this doesn't account for other power usage of the phone. Does your phone run for 2 days normally? It will be less when running this app, possibly a lot less.
But wait! We can put the phone into low power mode and eek out maybe another couple days which is long enough for the rescue team to have a good chance at finding you. Except low power mode does stuff like reduce radio power output because they are a massive power draw. Oh so lets just stop all the apps so the CPU is chewing up less processor time and eek out even more run time from this phone battery. Great, now your life depends on your installed piece of shit phone apps not trying to be helpful and autostart itself back up so you can get your tweets and Facebook status updates. Great fucking plan.
If you are lost in the wild and want this app to help save your life I hope you have a car handy or some other massive power source for the scale of a smart phone and the charger to go with it. Otherwise expect your phone to die before anyone can find you.
I find it extremely interesting when airplanes crash into the ground but that doesn't mean I want to see it happen with any kind of regular occurrence. In fact "interesting" sounds like the kind of polite thing you tell someone to not hurt their feelings when their experiment doesn't meet their expectations and you don't want to let them down hard.
This whole thing looks suspect as fuck and like physics just doesn't agree with the people who came up with it.
(Score: 3, Informative) by pTamok on Friday December 29 2017, @04:54PM (2 children)
You might not need a helicopter if a tethered balloon would work (or even an untethered one, if the equipment is cheap enough) - these days, you could use a drone.
The point is, if you can easily get line-of-sight , then the phone tells you where it is GPS-wise - you don't need to be running a detailed search from a helicopter. The phone doesn’t need to be transmitting continuously, either - it could have a duty cycle of 'squawking' every minute or so.
If the phone is putting out a predictable signal RF-wise, there are techniques that can be used to recognise the signal below the noise floor (which is how GPS operates routinely [gps-inside.com]), increasing the range at which the signal can be detected.
If you are doing serious wilderness travel, you might want to invest in a PLB EPIRB [wikipedia.org].
(Score: 2) by frojack on Friday December 29 2017, @07:55PM (1 child)
For Pete sake, just send a Stingray up in an airplane looking for a regular cell phone connection beacon instead of dicking around with wifi.
One loop route over Spain at 30,000 feet ought to do it. (At last a valid use for a Stingray!)
(If I'm in the bush I'm going to be turning off wifi and bluetooth anyway just to save power). I'll also drop to 3G or even 2G if the phone supports it).
No, you are mistaken. I've always had this sig.
(Score: 1) by pTamok on Saturday December 30 2017, @12:03AM
That might work, but the WiFi approach has some merits: not least, if you are out in the bush with no phone signal, it makes sense to switch your phone into 'airplane' mode to stop it wasting power by sending full-power phone transmissions to look for non-existent base stations. This depletes your battery faster than when you are in a well-covered area. Much faster. Having a well-designed Wi-Fi app that turns Wi-Fi on and off every few minutes then sleeps until the next chirp will have a lower battery drain.
As some people point out, this adds to the burden of equipment that SAR groups would need to carry, which is not ideal.
(Score: 2) by urza9814 on Friday December 29 2017, @06:16PM (6 children)
I think the biggest concern is that you have no idea if anyone is actually using this app, so it's just one more thing that the search party might have to look for. They could be transmitting on wifi, they could be transmitting on ham bands, or FRS emergency bands, or...? Someone better be building an SDR device that can track all of those!
But if you use it in specific areas it could work...ie, you make it clear with signs/outreach that a certain national park or popular hiking spot is using this wifi system, and that hikers should install this app before they come. Then, you install a couple high gain antennas on the nearby high points. With the right antenna setup you can reach over a hundred miles with unamplified wifi...of course you've only got a good antenna on one side here, and you might not have line of sight, but if you do it right you should be able to cover at least a couple square miles per antenna. Or as pTamok posted below, use drones or balloons to scan as required.
As for battery life...that's easy enough to solve, you don't need a freakin car, you just need a battery bank. I often have a 10 amp-hour battery in my pocket beside my phone...it's a bit smaller than the phone itself, and that capacity is around three times the phone's internal battery. And I've seen some newer ones that can fit 15 amp-hours in a pocket. If you aren't using the phone for anything while hiking, leave it at home so you don't break it. But if you do plan on using it, you'd almost certainly want to bring a battery anyway, so that should easily triple the phone's runtime.
Finally...your phone is constantly sending out radio pings anyway. I don't see why periodic transmissions on wifi would drain it faster than the existing periodic transmissions on 3G/LTE. So if it normally lasts a day or two in your pocket, stick a battery in the other pocket and it might be able to transmit like this for a week.
Seems like the best system you can get without a purpose-made device...and those already exist for anyone who wants one, but I'd bet most hikers don't bother. And those aren't necessarily better -- some transmit your exact GPS location to a network of satellites, but others can only give an approximate area and rely on a separate radio beacon to guide rescue workers to you once they arrive. And those are usually designed to last 24 hours, so depending on what kind you get, that secondary beacon might not last long enough either. And at that point you might still benefit from this as a secondary emergency beacon that you can keep powered off until you hear helicopters...
(Score: 2) by Knowledge Troll on Friday December 29 2017, @06:21PM (2 children)
Amp-hour isn't the measure of stored energy, watt-hours is. Runtime will be based on watt-hours not amp-hours. You can roughly estimate the watt-hours given the battery voltage and amp-hour rating but it's nicer if the manufacturer reports it to you because that simple estimate is based on a static battery where it's operation is quite dynamic.
(Score: 2) by urza9814 on Friday December 29 2017, @06:45PM (1 child)
True, but I've never seen one that actually reports the capacity in watt-hours, they always use amp-hours at a given voltage (5V in this case). And it's not just USB battery packs either...from AAs to phone lithium cells, every battery I've ever seen reports the capacity as amp-hours at a voltage.
(Score: 0) by Anonymous Coward on Friday December 29 2017, @08:29PM
It's usually not at 5V, even when the labelling seems to claim that. Assuming it's not a complete fabrication to start with, it's generally the sum of the rated capacities of the Li-ion cells in the battery bank, and thus should be multiplied by 3.7V; the amp-hours at 5V would naively be calculated as 3.7/5, or roughly 75%, of this figure, but allowing for the inefficiency of the boost converter, you might actually get 60%.
(Score: 2) by frojack on Friday December 29 2017, @07:59PM (2 children)
Presumably someone going into the bush might happen to mention it, don't you think? You took the trouble to install it, why wouldn't you let people know?
But mere availability in any app store will have the entire country swamped with false alarms. It will become useless.
No, you are mistaken. I've always had this sig.
(Score: 2) by frojack on Friday December 29 2017, @08:05PM
Also, people going into the back country away from any other source of help already know about PLBs and
https://www.rei.com/learn/expert-advice/personal-locator-beacons.html [rei.com]
No, you are mistaken. I've always had this sig.
(Score: 2) by urza9814 on Friday December 29 2017, @08:20PM
Right, but that means the person you told needs to first notice that you're missing, then give that information to rescue personnel, then they've gotta get the equipment to track it, and that takes time while your battery is draining. The faster they start looking for it, the better -- ideally before they know anyone is even missing if they can set up permanent receivers.
Much like the existing satellite beacons -- the satellites are always there, always listening, so as soon as you activate it the rescue team immediately knows your location. They aren't waiting around for someone to say "Hey, this guy went missing and by the way he's carrying a beacon".