There are a number of reasons for using mobile phone locator devices, and some of these are more legitimate than others. One good reason of course is simply that you have lost your phone. Another very understandable reason is concern about the safety of the owner of the phone. This could include parents keeping track of a son or daughter who is out late at night, or employers or relatives of a traveler visiting a remote and dangerous location.
In these situations, the owner has probably consented to allow a tracking device to be installed on his or her mobile. On the other hand, it has been known for such procedures to be undertaken without permission, for instance by a wife who does not trust her husband, or an employer checking up on an elusive employee. It must be emphasized that tracking someone’s cell phone location without that person’s knowledge is a criminal offense.
Assuming that your reasons for wanting to use a mobile phone locator device are legal and above board, how does it actually work? One way is through triangulation, based on the fact that wherever a mobile is at any given moment, it sends a signal to the nearest cell phone tower or “pings” it. A tracking application will attempt to detect two other towers in the vicinity, and lines drawn through the three towers will create a triangle within which the phone will be located. This is a fairly rough and ready approach, and it would not work in a remote area where there is not good coverage. A similar method is via WiFi, as mobiles will also send an automatic signal to a WiFi hot spot. If the hot spot has its own IP address, the phone can be located quite easily. However if it is a shared address and the other owner lives a long way away, obviously this will not work.
The most accurate mobile phone locator methods work by devices installed on the phone itself. These can be either hardware or software devices. Obviously, if you are doing this without the owner’s knowledge, hardware is the easier way to go, but there is always the risk that the owner could spot it, or that it could become accidentally dislodged.
The most commonly used method is via a GPS tracking device installed on the mobile. This can be extremely accurate, but there are several points to bear in mind. A GPS device needs to have nothing between it and the sky, so it will not work for phones that are indoors. Another proviso is that some GPS tracking applications are developed for use in a single time zone, so if mobiles are taken to a different time zone, this makes it difficult to interpret the information that is sent back. If the tracking is required for someone who is traveling the world, it is essential to check not only that the system is one that will adapt to time zones, but also that the application will work either with a global roaming SIM, or on the local SIM in that country.
There are several free GPS mobile phone locator services which you can download. For instance the Google Latitude software can be installed direct from the Google Latitude site, and can be used on non-GPS enabled phones as well. To stop you worrying about your children or friends, and gain peace of mind, this is the easiest way to go.