One of the most important capabilities of modern cell phones is that they almost always can identify their location. Because of that, they can give directions, show places of interest and provide recommendations. In this article we will discuss ways in which cell-phones are currently being tracked and take a look at how cellphones are able to identify location.
GPS is short for Global Positioning System. GPS was first created by the government in 1960s and was allowed for civilian use in 1980s. GPS devices work by connecting to satellites and getting signals from them. Nowadays almost every smartphone, including iPhones and Androids, has a GPS location sensor built in.
Regular GPS location sensor works well outside, but may have trouble connecting to required three satellites to identify location, especially in metropolitan areas such as New York, Chicago or Downtown Los Angeles.
Another reason for GPS not being very helpful in urban areas is that after finding the satellites a phone needs to download the information about where the GPS satellites are going to be in the next four hours. Depending on the signal strength, this might take a long time, yet full GPS service starts only when this information is downloaded to the phone.
This is where Assisted GPS or A-GPS comes to help. Cellphone service providers can now send the data about satellite locations over a Wi-Fi or regular cellular network, which is a lot faster than a satellite connection. This may result in GPS starting time going down from 45 seconds to about 15 seconds.
While Assisted GPS is much faster than regular GPS, it still requires a time period to download the information about future satellite locations and thus might take unpredictably long. Synthetic GPS uses computing power of a smartphone processing chip to forecast the location of satellites in advance. With data stored in the phone itself, it can take 2 seconds or less for such a phone to get fully started with a GPS.
Most modern phones operate on GSM networks. A GSM network is a cell network, meaning that in order to operate a GSM phone needs to connect to a cell. There are five kinds of GSM cells. They are defined by the position of antennas they are using. All antennas in a GSM network have unique numbers assigned to them. Cellphone carriers can identify which cell a phone is using and how far it is from another cell. Knowing all this information, a carrier is able to tell a phone’s location. This method of location identification works extremely well in high-density urban areas, because such areas usually have a lot of cells and a lot of antennas in close proximity to each other.