GPS Gadgets: How Do They Guide Us?
October 20, 2008
You may wonder why GPS gadgets cost as much as they do. Learning about the technology behind them may help make the cost a little easier to accept. More often than not, we are seeing GPS systems being automatically included in PDAs and cell phones as well as the newest car models. This author isn’t an engineer or scientist, so this article is a summary of how GPS systems operate. Complete technical details can be retrieved in other articles posted on the Internet.
The ABCs of GPS
Did you know that there are approximately 2500 satellites currently orbiting the globe? Rather a significant percentage of them are GPS system satellites. Only about 36 actually are operative – the others are retired GPS satellites. A low-power signal is transmitted by the satellites which can be picked up by the GPS system in your car or cell phone. In order to determine an exact position, the GPS system evaluates its distance from three of these satellites.
You may be curious to know what a GPS satellite looks like. Photos can be found on the net, but essentially they are around 17 feet across with soloar panels that are spread on either side. They run on solar power and as additional insurance have backup batteries installed. They are designed to be functional for a minimum of ten years and weigh approximately 2,000 pounds. There is a “senior” satellite that has been in operation since 1978. That one goes around telling all the junior GPS satellites how challenging it was in his day and how easy the younger ones have it. Just a little satellite humor there.
But Seriously
So what devices qualify as GPS receivers? If a device is capable of receiving the signals output by GPS satellites, it can be regarded as a GPS receiver. There was in all probability a GPS receiver on that cruise ship you were on last summer, another in the taxicab you needed to the airport last week and then there’s that Navigon 7100 GPS that your boss just bought for his auto. Portable GPS systems for public use are averaging around $300, give or take a few dollars. A price tag of $300 isn’t that out of line when you consider that you didn’t have to pay for all those gps satellites to be built and launched into space, nor do you have to pay a fee to use the signals from them.
The US government is responsible for paying the costs involved in manufacturing and launching satellites into orbit.|Our government here in the US has resolved to take on the costs involved in creating this network of GPS satellites. Your primary job is to turn on your GPS system and enjoy the easier travel that it brings you. So now you should have a fairly good understanding of what goes on behind the scenes when you switch on your GPS system.
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