Category:Navigation

Summary

Global positioning system also known as GPS is a technology that utilizes radio signals produced by satellites. Since a mobile phone already works like a two-way radio when communicating with cell towers, the GPS capability simply extends the radio signal reach to space satellites. [1] Smartphones already have GPS resources that authorize Emergency Response Teams to locate its location through a 911call.

GPS is based on a Java-based platform that has permission to the service provider’s database. Location tracking and giving directions to and from destinations are some of the more common uses for this technology. [1] The device receive can be included inside the phone or accessed through wireless (i.e. Bluetooth) connection. In order for the navigation-related information to be transmitted, users must have a calling plan that supports the transmission of maps and supporting data. [1]

How it works

The GPS navigational systems are supported by a network of 27 satellites. At any given time, a minimum of four satellites signals is accessible to any one point on the Earth. [2] Since the cell phone mimics a two way radio, it transmits radio waves to the satellites. A process referred to trilateration is able to pinpoint the exact location of the mobile phone. Trilateration is a series of three satellites simultaneously attempting to pinpoint the mobile’s phone location. A fourth satellite receives data from the previous three satellites and determines the match.

Distance calculations are made on how long it takes the radio signals to travel back and forth between the receiver (mobile phone) and satellite. [2] The mapping capabilities are displayed on the phone’s screen via the cellular provider’s database. [2]

In order for a GPS device to work, there must be a clear line of sight between the receiver (mobile phone) and the sky. [3] There are occasions when this is not possible; therefore, the mobile phone would not receive signal information or will transmit and receive inaccurate signal information to and from the satellites. Using your mobile phone inside a building, beneath trees, or nearby a tall building may cause these problems to occur. [3]

Enhanced technology has allowed for assisted GPS. Assisted GPS leverages the cellular network through the use of cell towers. These servers are able to process incoming data at much higher rates than GPS receivers, so information is transmitted quicker, and is typically more accurate than what a mobile phone can relay on its own. [3]

There are two ways to leverage your mobile phone as a navigation device. One is by using server-based navigation, meaning that the map data for your route is sent to your phone as needed. The other is to download an all-inclusive application that stores entire maps on your device. [6]

Server-based navigation

Mobile phone service providers, (i.e. ATT, Sprint, and Verizon) can  provide GPS and traffic information for their customers for a daily or monthly fee. This allows the mapping data not to be stored on the phone but accessed wirelessly from the provider’s network on an as needed basis. Another server-based solution, Google Maps, provides similar functionality for free, but only for users of Android devices. [6] Compatibility limitations restrict iPhones to Google’s static maps only, without turn-by turn directions. [6] With the Google and iPhone exception, server-based navigation provides menus and features similar to those of navigation apps or portable systems, including spoken and onscreen turn-by-turn directions, traffic info, and a point-of-interest menu of destinations like restaurants, gas stations, and stores. [6] This allows the user full access to automatically updated databases for mapping without leveraging the capacity of the phone’s memory. However, this approach does consume bandwidth.

GPS-capable smart phones and apps

Smart phones have GPS receivers and mapping software, allowing users to download an app that gives them all the functions and features of a dedicated GPS unit. [6]

Popular Navigation Apps

Fun Facts

Navigation was primarily leveraged for Airplanes and ships but the growing use of the mobile phone has extended the use of this function.

Listed below are a few facts regarding the use of navigation:

10 Fun Facts [8]

1. Every GPS satellite orbits the earth at-least once every 12 hours. Estimate flight distance is 12,500 averaging 7,000 miles per hour

2. It takes 4 satellites to identify your exact location, rare cases three satellites maybe used.

3. President Ronald Reagan orders the military to produce GPS for civilian purposes following a disaster in 1983. Flight 007 for Korean Air Lines was shot down for violated Soviet Airspace in which 269 passengers died.

4. NavStar starting point was the name given to the U.S. military global positioning system.

5. Each GPS satellite has atomic clocks and time signals are sent alongside the location tracking data. GPS receiving devices can determine the current time in 1/100 billion seconds. These signals are used to synchronize the time on your cell phone.

6. Ground antennas spread throughout the world are used to adjustment the past of the satellite and the time they sync to the mobile phone.

7. GPS is owned and placed under the control of the Department of Defense.

8. By 2000, civilian GPS had removed a feature called “choice is available” (Selective Availability –SA). This move caused a random approximation error of up to 328 fee thus leading to a reduction in accuracy (Intentional accuracy difference for military advantage). Selective Availability feature was deactivated on 01/05/2000.

9. During the Gulf War in 1991, many U.S. soldiers were equipped with GPS devices and functions of the Selective Availability turned off during the war to give an edge to American military might.

10. GPS works on a session system. This system was further upgraded with the addition of a new satellite resulting in an accuracy increase the system became more useful.

Android versus IPhone

Both phones successfully run Google Maps, it has been stated that the Android's mapping feature was a bit faster than the iPhone's. Neither phone’s GPS was a standout from the consumer’s testimony; however, there was one feature that solidified the iPhone vs. Droid debate. The turn-by-turn directions offered by the Android were clearly the favorite among consumer testimonies.