Comments on: Get “My Location” sans GPS http://liftlab.com/think/nova/2007/12/01/get-my-location-sans-gps/ mind/tech bazar from outer space Sat, 22 Nov 2008 13:44:21 +0000 http://wordpress.org/?v=wordpress-mu-1.2.1 By: Juan http://liftlab.com/think/nova/2007/12/01/get-my-location-sans-gps/#comment-493683 Juan Thu, 04 Sep 2008 20:36:50 +0000 http://liftlab.com/think/nova/2007/12/01/get-my-location-sans-gps/#comment-493683 Hi everyone. A few days ago, I was surfing the web and I found out a project that works over most mobile phones which lets you know where your friends are in real time and update your status in twitter. It´s called Dimdix. On their website they say you don´t need a GPS system to detect your location. Does anyone know how this works? I´m using a Motorola L7 and amazingly it detected my location. I cannot stop thinking of all the things I could do with it. If anyone wants to take a look you can go <a href="http://www.dimdix.com" rel="nofollow">here</a> Thanks, Regards, Juan Hi everyone.

A few days ago, I was surfing the web and I found out a project that works over most mobile phones which lets you know where your friends are in real time and update your status in twitter. It´s called Dimdix.

On their website they say you don´t need a GPS system to detect your location. Does anyone know how this works?

I´m using a Motorola L7 and amazingly it detected my location.

I cannot stop thinking of all the things I could do with it.

If anyone wants to take a look you can go here

Thanks,

Regards,

Juan

]]> By: Jean-Marc Liotier http://liftlab.com/think/nova/2007/12/01/get-my-location-sans-gps/#comment-448575 Jean-Marc Liotier Sat, 01 Dec 2007 15:52:32 +0000 http://liftlab.com/think/nova/2007/12/01/get-my-location-sans-gps/#comment-448575 > This uncertainty is claimed to be around one-quarter to three > miles of a user’s location. Actually cellID can provides even higher accuracies in dense environments or much worse ones in desert ones. Here is an extract of the "cell of origin" article from Wikipedia which is coherent with what I learnt about cellID methods a few years ago : "Crude COO positioning considers the location of the base station to be the location of the caller. This is not very accurate, as the majority of mobile network cells are projected from an antenna with a spread of 120o (i.e. three mounted on a mast to give complete coverage) giving a signal coverage area with the base station at one corner, rather than the centre. Omnidirectional cells may be used in rural locations (which typically have large ranges and hence uncertain locations for phones within them) and in cities (where they may have ranges of a few hundred metres). The underlying issue is that mobile phone networks are optimised for capacity and call handling rather than locating phones. Most commercially implemented systems rely on 'enhanced' COO. In the GSM system this relies on the fact that the phones constantly measure the signal strength from the closest 6 base stations and lock on to the strongest signal (the reality is slightly more complex than this and includes parameters that each individual network can optimise, including signal quality and variabilty. Most networks endeavour to optimise for minimum power consumption, but the overall effect approximates to each phone locking onto the strongest signal). All networks generate 'splash maps' predicting signal coverage when planning and managing their networks. These maps can be processed to analyse the area which will be dominated by each base station and to approximate each area by a circle (the actual area of coverage may not be exactly where predicted... and in any case will be an irregular shape, rather than a circle)." > This uncertainty is claimed to be around one-quarter to three
> miles of a user’s location.

Actually cellID can provides even higher accuracies in dense environments or much worse ones in desert ones. Here is an extract of the “cell of origin” article from Wikipedia which is coherent with what I learnt about cellID methods a few years ago :

“Crude COO positioning considers the location of the base station to be the location of the caller. This is not very accurate, as the majority of mobile network cells are projected from an antenna with a spread of 120o (i.e. three mounted on a mast to give complete coverage) giving a signal coverage area with the base station at one corner, rather than the centre. Omnidirectional cells may be used in rural locations (which typically have large ranges and hence uncertain locations for phones within them) and in cities (where they may have ranges of a few hundred metres). The underlying issue is that mobile phone networks are optimised for capacity and call handling rather than locating phones.

Most commercially implemented systems rely on ‘enhanced’ COO. In the GSM system this relies on the fact that the phones constantly measure the signal strength from the closest 6 base stations and lock on to the strongest signal (the reality is slightly more complex than this and includes parameters that each individual network can optimise, including signal quality and variabilty. Most networks endeavour to optimise for minimum power consumption, but the overall effect approximates to each phone locking onto the strongest signal).

All networks generate ’splash maps’ predicting signal coverage when planning and managing their networks. These maps can be processed to analyse the area which will be dominated by each base station and to approximate each area by a circle (the actual area of coverage may not be exactly where predicted… and in any case will be an irregular shape, rather than a circle).”

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