On Thu, 19 Jan 2012 16:55:05 +0000, Gordon H
<Gordo...@g3snx.demon.co.uk.invalid> wrote:
>>An excellent idea, finally a good use for a smart phone, simple to use
>>but very effective. We all appreciate any of us can have an accident, but
>>too many people go out unprepared There is no way of really stopping that
>>but at least it should be easier to find them, perhaps not 100% of the
>>time but it all helps to save time and resources.
>>
>Does a smart phone work at the bottom of a gully?
>Straightforward question, ie - does it use satellite communication or
>normal mobile phone networks.
Feel free to try my links while you are out and about.
http://www.4theweb.co.uk/test/locate.htm Lat long
As far as positioning is concerned mobile phones use both satellites
and the phone network. Outdoors, you should be able to see some
satellites though it might struggle in thick woodland.
Of course if you have a smartphone there are plenty of apps that will
tell you where you are. The biggest problem is getting a good enough
Internet connection to pull in maps and so forth. The SARLOC app has
the advantage of using very little bandwidth to transmit your location
without transcription errors that you might get if you tried to copy
co-ordinates into a text message. Basically it works just like the
example above except that it stores the data so the SAR team can see
it (mine doesn't, but could very easily with a few extra lines of
code).
I guess they send a URL like
http://www.4theweb.co.uk/test/locate.htm?name=userid and store the
location in a database or textfile with an id of 'userid' (which
would be different for each person lost)
But all methods need /some/ signal and that can be very variable. the
govt would be better off spending money on that infrastructure, rather
than messing around with fast trains for fat bottomed business people.