Determining How GPS Units Guide Us
Whenever we have some understanding of a technology such as GPS systems and how they function, it helps us value that technology and understand its cost. More often than not, we are seeing GPS units being automatically embedded in PDAs and cell phones as well as the newest car models. This article will explain in words that the average person can understand how GPS systems work. Full technical details can be found in other articles published on the Internet.
GPS 101
Encircling our planet right now, you will find about 2500 satellites. Many of these are GPS system satellites. Only around 36 actually are operative – the others are retired GPS satellites. These satellites transmit a consistent low-power signal which is picked up by GPS receivers such as the unit in your car. By accurately measuring the distance from three of these satellites, the GPS system can compute its exact position on earth.
GPS systems satellites are about seventeen feet across when their solar power panels are fully expanded. Yep, they work on solar power and also have backup batteries installed for use when solar isn’t available. They are built to last ten years (knock on wood). The longest working satellite is from 1978. His task is to tell the newer satellites how tough it was in his time and how much better the new models have it. Just kidding!
But Seriously
So what is a GPS receiver? Any electronic device that is able to receive signals sent by the GPS satellites is a GPS receiver. There was probably 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 purchased for his car. Portable GPS systems for public use are averaging out around $300, give or take a few dollars. Considering you didn’t have to invest anything to design, build and launch the satellite into space, $300 is a very conservative price.
It’s the US government who bears the price for constructing the satellites and launching them into space. So you can sit back and relax in your car, knowing that this network of satellites will promptly and dependably direct you to your destination. So the next time you power on your GPS system, you should feel that you have a functioning knowledge of how GPS works.