A feature-rich cellphone allows MMS, SMS, calls, Internet access, FM radio, and also a GPS unit. This is the best example of an integrated circuit (IC) that allows same radio signals to provide you with different data on a single device. We offer an overview of radio signals for GPS and more.
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The Radio World for Communication and Broadcast – Choosing Right Medium for the Right Place
Before we look at Radio World and GPS, lets understand the need for a medium for communication. Almost everything that is transported requires a medium. For physical goods, you need some vehicle. For communication, broadcasting, and navigation, the mediums involved may include vacuum (for the satellites in earth's orbit), different levels of atmosphere (air), water, and land. Communication and broadcasting is possible only when you have the right technology in the right place.
A simple example – you can easily communicate with your friend on the earth's surface, but if you and your friend were in the vacuum of space, you won't be able to hear your friend no matter how hard you try. The reason, of course, is because on earth air acts as a medium to carry signals from your friend's throat to your ears. Then biology is involved– intercepting the sound and converting the signal to impulses to send to the brain to interpret. This is not much different from the various technologies employed in the radio world today.
Among the most common mediums for communication and some broadcasting are copper and lead wires.There are also several types of wireless systems, with almost all of them being dependent on radio signals. The other medium is light signals. Light signals (photons) are one of the fastest mediums that can carry data to anywhere in the entire universe, but our scientists have not yet found a method to utilize them in other than fiber-optics. If only they could, the world would have uninterrupted communication: no GPS signal blackouts, no disturbance in your wireless music, and no area where your cellphone signals won't work!
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The Radio World and GPS – An Introduction
So what does the above has to do with Radio signals and GPS? Radio signals are short electromagnetic waves that are used to carry data about just anything from one place to another. Once the data is received by your unit, it is interpreted to display something or play some sound to you. In a manner similar to the way human hearing works, the GPS receivers collect radio waves using an antenna that are sent or conducted to a separate processing chip for interpretation.
Basically, when we refer to "wireless," we are speaking of radio signals. WiFi, WLAN, Bluetooth, and almost every other wireless device depends on radio signals to receive and send data.
For wired ones, you do not need radio signals. The copper wire (in twisted pair) or the center lead (in coaxial cable) serve as good conductors that offer less resistance to the data being carried. Except for very short distances, the way transmission modes work are the same.
For very short distances, like from your computer to your printer, the data need not be changed into an analog (waveform) format. But for longer ranges, the data is transformed into analog format, superimposed on the radio signals, and are released.This is how AM and FM radio work.
For these broadcasts, any device capable of receiving and interpreting the data can strip out the data from the radio signal and convert it back to digital format for further processing.
The same process is employed in GPS also. The GNSS satellites convert data into analog signals before superimposing them on radio signals. Converting into analog form implies a signal that shows +y for ones and -y for zeros. The end of transmission (EoT) is indicated by x=y=0. These radio signals cross the vacuum and different atmospheric layers to reach your GPS unit. Once your GPS antenna receives the radio waves, it sends it to the GPS receiver which filters the additional noise gathered during the travel of radio signals and then, you get the final output on your GPS display.
The only disadvantage of radio signals is that they lose strength over long distances and that they cannot penetrate solid substances. This is why you experience incorrect GPS observations or no signals. Still, radio world and GPS technology has advanced to handle weak signal GPS to offer you a lower probability of errors.
This series on GPS aims to offer you details on the essentials of GPS. It covers the GPS signal strength, measuring GPS accuracy, and factors that affect the GPS accuracy. Check these articles and feel free to ask further information on essentials of GPS.