Emergency Scenarios With No Signal

[etimmy22]

Ive looked all day and cant find an answer. If you are stranded in a remote area with absolutely no coverage can you use gps to send your coordinates to rescuers? If so, how is it done? If not, why cant it be done?

 

[dylanthecat]

Won't work. GPS is a receive only service. No transmitter. The vultures will eat you.

 

[etimmy22]

Ok. Why arent phones able to transmit? Curious because you can buy those locator beacons for like $200.

 

[tonydelite]

Ok. Why arent phones able to transmit? Curious because you can buy those locator beacons for like $200.

.

As was said before, GPS is a one-way service. Emergency locator beacons can use GPS for positioning, but use radio waves to send out the distress beacon to the SARSAT system. The cheaper ones use radio only, and rely on radio triangulation for location.

To add all of this to a phone would add several hundred dollars in cost, and increase the size of the phone dramatically. It could be done, but no one wants to pay $1000 for a cell phone that is the size of a brick.

If you're really worried about this, then you should probably buy your own emergency locator beacon.

EDIT: I forgot to add, if every cell phone had the ability to send a distress beacon to the SARSAT system, search and rescue teams would be completely overloaded with the amount of false alarms they got. It takes a lot of money, resources and manpower to deploy a search and rescue team.

 

[ilikemoneygreen]

This may be just an idea, but try thinking about taking the transmitter out of the equation. Try thinking of the device as it is right now. What if gps company just gave the rescuers the coordinates? lol i know if i was lost in the mountain and was using GPS i would hope one of my family members would go "oh hey rescuer, hes got gps, can you call the company and get his location?" The phone recieves the gps signal...but its not like the company loses the data once it is transmitted.
Same thing for serial killers... i bet if they couldnt triangulate a suspects location one night becuase he was out of range, i hope they would have the ability to get a warrent and get those gps coords.

 

[tonydelite]

GPS doesn't work like that. If you do not have a cellular signal, there is no way anyone else could access your coordinates.

GPS satellites are constantly sending out positioning information. a GPS device looks at this information, and determines its own position by triangulating the data between 4 or more satellites. The more satellites it can see, the more accurate the information is. This process is completely invisible to the satellites themselves... they are not aware of any receivers. As far as they are concerned, they are just mindlessly spitting information into the void. There would be no way to remotely read someone's coordinates on a GPS only device, which is exactly what your phone would be if it had absolutely no cellular signal whatsoever.

If you were lost in the mountains with only a GPS receiver, no one but you would know where you are.

 

[ilikemoneygreen]

GPS doesn't work like that. If you do not have a cellular signal, there is no way anyone else could access your coordinates.

GPS satellites are constantly sending out positioning information. a GPS device looks at this information, and determines its own position by triangulating the data between 4 or more satellites. The more satellites it can see, the more accurate the information is. This process is completely invisible to the satellites themselves... they are not aware of any receivers. As far as they are concerned, they are just mindlessly spitting information into the void. There would be no way to remotely read someone's coordinates on a GPS only device, which is exactly what your phone would be if it had absolutely no cellular signal whatsoever.

I disagree but will have to do more reseach into this to back up my disaprroval. I know how gps works, but i also think this information can be tracked. "mindlessly spitting information" haha, i am completly disaproving with that. You mean to tell me their is no device id? nothing? how do i get my own coordinates then and not someone else's?

 

[tonydelite]

You mean to tell me their is no device id? nothing? how do i get my own coordinates then and not someone else's?

Correct.

You get your own coordinates because your device is figuring it out. The coordinates are not "sent" to you. Your GPS looks at the sky, sees the satellites, and figures out its own position relative to where the satellites are.

You can easily look this up on Wikipedia or any number of websites if you don't believe me.

 

[dylanthecat]

Tony is correct. Works just like AM or FM radio. The transmitters mindlessly spit (I like that) information out without caring who receives it. Your GPS receiver does the math and tells you where it thinks you are.

So if no one knows where you are, but you have a GPS, are you still technically lost?

 

[takeshi]

EDIT: I forgot to add, if every cell phone had the ability to send a distress beacon to the SARSAT system, search and rescue teams would be completely overloaded with the amount of false alarms they got. It takes a lot of money, resources and manpower to deploy a search and rescue team.

They're already getting ridiculous calls as it is from people who are ill-prepared but think they can rely on the distress beacon to save them from lack of experience, ignorance, stupidity etc. I recall reading a recent article about people using such systems and wasting emergency services resources for trivial items.

This may be just an idea, but try thinking about taking the transmitter out of the equation.

You can't take it out of the equation. It's an essential part for you're talking about. Your location is determined locally on your device. No one else knows your location unless it is transmitted somehow.

What if gps company just gave the rescuers the coordinates?

How are they getting your coordinates? Carrier pigeon? Magic?

The phone recieves the gps signal...but its not like the company loses the data once it is transmitted.

How is it transmitted with no cellular coverage?

i hope they would have the ability to get a warrent and get those gps coords.

There's nothing to obtain via warrant if the coordinates are not transmitted back.

I disagree but will have to do more reseach into this to back up my disaprroval. I know how gps works, but i also think this information can be tracked.

You really should read more on GPS. Again, your location can be tracked if it transmitted. Without cellular coverage and no other method of transmitting your device isn't going to provide your location to anyone.

You mean to tell me their is no device id? nothing? how do i get my own coordinates then and not someone else's?

How is the device ID relevant for calculating your position? In a very basic sense, your receiver is triangulating your position using the GPS satellite signals (there's a bit more to it but the details aren't really germane to this discussion). You obtain your coordinates because your GPS receiver calculates them. You don't get anyone else's because you don't have access to their GPS receivers from your own device and your receiver has no way to determine the coordinates for a location unless your receiver is at that location. If a device ID communicated back to "the GPS company" was required then stand-alone GPS units would be useless as they (you guessed it) don't transmit anything.