How Mobile GPS Enables Location Based Services

Thinking of using mobile GPS to find your friends on your new smartphone? Think again. The global positioning system (GPS) is under strain. Why? Mobile device consumers, the military, and businesses demand greater accuracy and reliability. GPS also has a direct impact on location-based services.

In 2009, the U.S. House of representatives asked the GAO (Government Accounting Office) to study how long GPS service would last. Its report concluded that the Air Force, responsible for maintaining 24 GPS satellites is struggling to maintain service levels.

Starting in 2010 until the end of FY 2014, military and civilian users may experience service level drops approaching 80% of capacity. The timing is bad. Four out of five mobile phones, according to the NPD group in the 4th quarter of 2009, had GPS capabilities.

Potential problems?

• Canceled international flights or re-routing
• Lost accuracy in enhanced 911 response to emergency calls, especially in urban and mountain areas
• Increased civilian “collateral damage” in areas of war
• Lost or inaccurate signal levels for professional surveyors and others requiring pinpoint location accuracy
• Reduced coverage for location-based services via cell phones in large cities, mountainous areas and heavily forested areas of the country.

Moreover, the three major suppliers of GPS mapping databases–Navteq, owned by Nokia, Tele Atlas, part of TomTom and Google–agreed in a 2010 International CES panel that personal navigation devices (PND’s) are not disappearing. They’ll continue competing with mobile phone navigation further straining satellite performance. Meanwhile, Garmin dropped out of the navigation database software business as PND prices dropped below $100.

In the past, phone-based navigation was mainly used by pedestrians, but Google changed the game when it introduced turn-by-turn travel with Google maps.

But if you thought that its future is navigation, think again. Location-based services and social networking will dominate mobile GPS as smartphones increase, further reducing satellite performance. What will be the impact on geotagging and our 4G wireless world?

Mobile GPS: How the System Works

Most people take the system for granted as they watch their vehicle screens light up with colorful maps or mobile phones display their locations. Behind the scenes, however, a complex system is working overtime to deliver latitude and longitude information to wireless devices.

A few snippets of info about our global system. 

• At least 24 active satellites circle the Earth, although today there are more than 30, including a couple of spares. Their orbits spread out so no matter where you are, you’ll have at least six of them in your line of sight.
• Each satellite goes around the world once every 12 hours. The satellites are above us 12,500 miles (20,000 km) and move at roughly 7,000 miles per hour (11,000 km per hour). They have small boosters so they can adjust their path when needed.

  

• The first full constellation of 24 satellites went up in 1994. The first of those 24 satellites launched in 1989.
• To get a reliable position, your mobile GPS receiver needs to combine the signals from at least four satellites, although in some special cases, three is enough.
• The system went public due to a tragedy. In 1983, the Soviets shot down a Korean Air Lines flight after it entered Soviet airspace due to a navigation error. The incident killed all 269 passengers. This disaster resulted in President Ronald Reagan ordering the Unites States military to make the Global Positioning System available for civilian use when completed to avoid a repeat of similar air disasters
• NAVSTAR is the US military name for the Global Positioning System.
• Besides navigation, the system also determines time.
• Every satellite has multiple atomic clocks. Signals between the satellites include the time stamp. With the help of these signals, a receiver determines current time within 100 billionths of a second, helping carriers synchronize base stations in cell phone networks.

Imagine early explorers sailing across the oceans searching for unknown worlds with only the stars to guide them. Next time you use your mobile GPS device, look up at the sky. The future awaits.

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