Optimal use of available GPS devices when stranded

Two scenarios are to be explored.

• Do you have mobile coverage? Yes?

Then just find out your gps coordinates, send them to your rescuer. And stay put. In case your location changes, resend them (sounds lame but essential). Since you are asking about battery life, it's okay to switch off your GPS (given the device[mobile/watch] provides that option) to save your battery(assuming you have passed on the coordinates already). Also, keep your mobile network on to contact the rescuer (again, sounds lame, but essential).

• No mobile coverage?

Your best bet is to use the GPS to find your way out. GPS only shows where you are located on earth. It doesn't give you any more information. In case you are using a mobile, there are apps(ex: maps.me) which allow you to have offline maps which can be used in mobile network-less regions (these maps need to be downloaded upfront using mobile network). In this case, you'll have to use this information to navigate out of your situation using the GPS. (GPS does not require mobile connectivity). Also, note that GPS does consume your battery based on the update interval. It's best to switch off your mobile network (since you have it not anyway) so that your device doesn't keep on searching for a network(which eats up your battery) and navigate out.

The reason I've added this answer is because there's an inherent assumption that mobile coverage is present in one or two of the answers and the comments provided for the same.

Another point to be noted. In case you are waiting for rescue and have no mobile coverage, GPS has zero value. You might as well switch the whole thing off :P

posted over 9 years ago

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Ricketyship‭

291 reputation 30 52 37 0

Use the GPS to determine your position and then text or email that to your rescuers. That will be the end of the GPS's contribution to the rescue process.

Staying put is generally best (saves your energy and ensures you don't move into an area they have searched and think you are not in) but that place should be safe and you should be discoverable in it. Ideally you would find that place and then send your co-ordinates.

posted over 9 years ago

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Kate Gregory‭

321 reputation 5 88 35 0

Take the batteries out and use them to start fires. You won't even need to encode your lat/lon in smoke signals, that feature is built in.

follow up (edited again - note that the question does not say the person is lost, just trying to get rescued) My answer sounds flippant, but seriously, if you can't move or send info out, it's useless. Maybe MacGyver could turn the GPS into a transmitter, but can you? You can use the batteries & wires to makes sparks, or maybe use the screen as a signaling mirror. Or, if it has an illuminated screen, use that as a signal at night. Other than that, your GPS is as useful as a brick.

posted over 9 years ago

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Pepi‭

161 reputation 0 34 16 0

Always mark or keep track of your starting point co-ords, or finish co-ord. Turn off the unit to save power and check once in a while to see if # are getting closer, you will find out fast if you are headed in the right direction. #'s will get closer. Play with it in your backyard and learn the capabilities of these new machines, awesome!!! Never rely on this tech though, learn the old fashion way first. They sure can help you to learn how to use a compass and topo map though!!

posted over 9 years ago

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user114556‭

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If you're not using the device to find your way, it is useless as far as the GPS functionality is concerned, no matter whether it's switched on or off.

If I know they are looking for me, would they pick up the signal, if I switch it on for short periods every now and again?

What signal? The GPS signal is sent by satellites, GPS devices receive this signal, they don't send out anything. A phone might send out a GSM/UMTS/LTE/whatever signal when trying to contact a base station, but that has nothing to do with GPS, and I'm not sure whether rescue services can use those signals to detect a phone; typically they use information from the base station to find the location of phones, but in your situation there would not be a base station in reach.

posted over 9 years ago

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Michael Borgwardt‭

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