Posts Tagged ‘how does gps work’

How does GPS work?

27th
Jan

Some interesting GPS trivia

  • GPS refers to the U.S. Department of Defense’s GNSS (Global Navigation Satellite System), also known as NAVSTAR. There are other GNSS around the world including the Russian GLONASS, the Chinese Compass and the planned EU Galileo system however NAVSTAR is the only fully-functioning GNSS at this time.
  • The first GPS satellite was launched in 1978.
  • A full constellation of 24 satellites was achieved in 1994.
  • Each satellite is built to last about 10 years. Replacements are constantly being built and launched into orbit.
  • A GPS satellite weighs approximately 2,000 pounds and is about 17 feet across with the solar panels extended.
  • GPS satellites transmit two low power radio signals, designated L1 and L2. Civilian GPS uses the L1 frequency of 1575.42 MHz in the UHF band. The signals travel by line of sight, meaning they will pass through clouds, glass and plastic but will not go through most solid objects such as buildings and mountains or under water (which is why Garmin haven’t released a GPS unit for submarines!).
  • A GPS signal contains three different bits of information – a pseudorandom code, ephemeris data and almanac data. This information identifies the satellite, its current status, date and time as well where it should be at any given time.
  • Transmitter power is only 50 watts or less.
  • It takes between 65 and 85 milliseconds for a signal to come from a GPS satellite to a receiver on earth.

GPS is a complicated subject so let’s get right back to the basics of GPS; what is it and how it works. As an example in demonstrating how GPS technology is being used, we will look at how it is helping the ground transportation sector to route vehicles more efficiently.

Making an informed choice about GPS systems

If you’re looking to invest in a GPS system you don’t necessarily need to know exactly how it works, just like you don’t have to know how a car works to drive one. You just get in and shift it into drive.

But understanding how GPS works can help you to make a better decision when it comes to choosing the best GPS system. Unfortunately many people who buy GPS systems don’t know much about them. They end up making the mistake of getting something that is overkill, with features they’ll never need and a price tag to match. In some ways it’s like buying a car without knowing that the more liters a vehicle’s engine has affects its power and fuel consumption – if you didn’t need the extra power why pay for a fuel guzzler? Then again buying a Prius when you need to tow a 240-foot super-yacht could be disastrous.

In a similar way, different GPS systems work in different ways, some are better suited to specific environments, some are free, and others have ongoing charges. By understanding some of the science behind GPS and how it works you can make sure you get the best GPS navigation system for your needs, or the needs of your business.

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