Jaeheon Shim
Hi! I'm Jaeheon Shim, a computer programmer and technology enthusiast who lives in Columbus, Indiana. I like contributing to open-source development projects on GitHub, working on my own web-based applications, and writing articles on my blog Learn The Technology. In my free time, I manage CAMEO's public website and provide free tech assistance to friends and family :).

Technology Tuesday Week 1: How does GPS work?

Welcome to the first ever Technology Tuesday Article! Thanks to everyone who submitted questions in such short notice. For those of you who have no idea what this is, you’d better read my article on Technology Tuesday.

Let’s get started!

Q:

My password is ************* (Actual text censored). Is this a secure password?

John Daves

A:

Well, according to howsecureismypassword.net, it would take a computer 3 million years to crack your password. So yeah. I’d say it’s pretty secure.

However…

The whole point of a password is that it is secret. By submitting your question, you literally just told an internet stranger your password. I’m not saying that I am a hacker or anything, but your password is no longer secure. I won’t tell anyone it, but what’s going to stop someone from torturing it out of me? I am sorry, but your password is no longer secure.


Q:

How do satellites work? How does this relate to GPS’s?

Anonymous

A:

Great question! I’m wondering why I haven’t written an article about satellites earlier. I’ll answer both parts of your question.

First, satellites are anything that orbits around a large body, in this case, Earth. The moon is a satellite. However, since you mentioned GPS I assume you mean the type of satellite that is artificial and makes satellite TV work.

Satellites are put into space to overcome the geographical boundaries that Earth has. For example, it is much more effective to capture large pictures of Earth from a satellite, rather than sending an airplane into the sky. We use satellites to provide many services that could otherwise not be provided from the ground. One of these services is GPS, or the Global Positioning System.

The Global Positioning System – commonly referred to by the acronym “GPS” – is a network of 24 satellites that orbit Earth at an altitude of about 20,000 feet. The GPS was originally designed and deployed by the US military for navigation, but it can now be used by anyone on Earth. They exist so that a device anywhere on Earth can calculate its precise location quickly and energy-efficiently.

These satellites broadcast a signal every interval, at the speed of light. On Earth, you are always receiving 3 out of 24 satellite’s signals. These signals transmit information about your location and the current time at regular intervals. But how can this calculate the position of thousands of people at once? By using the process known as triangulation.

http://www.physics.org/article-questions.asp?id=55

Let’s say that you are standing somewhere on Earth with three satellite signals within the reach of your GPS device. A common misconception is that the satellites calculate your position. This is not true. If you think about it, a satellite is probably used by millions of people at once to calculate their position. If a satellite’s computer had to calculate everyone’s location individually, it would probably overheat and become a flaming shooting star (Not really). Instead, your GPS calculates your position using the signals it receives from the satellites.

So how does this work? Referencing the picture above, if you know how far you are from satellite A (meaning you receive a signal from it), you know you must be somewhere on the red circle. Repeat this with the signals from the other two satellites, and your precise location will be where the circles intersect. It is as simple as that.

Of course, GPS is not a solution for situations where high precision is required. While a good GPS can potentially calculate your location down to about a feet, you really can’t get more precise than that because signal strengths will vary, and there are many factors involved. For example, the atomic clocks on the satellites will vary relative to Earth time.


Q:

How does a computer turn on?

Ben Genter

A:

When you press the power switch on a computer, a signal is sent to the motherboard which powers up the computer. Nothing I say could possibly add to this.

Just joking.

While you might just see a loading screen when you turn on your computer, a lot is happening behind the scenes once you press that power button.

POST

First, the computer goes through a process called the Power On Self Test. This process checks to make sure that everything on the computer is ok. For example, it checks if all the RAM is operational, if the CPU fans are running, and is the computer getting enough power. If an error is found, either a message is displayed on your monitor, or a sequence of beeps is emitted from the motherboard to help tech geeks diagnose your problem.

MBR (Master Boot Record)

Then, your computer searches memory mediums currently attached to it to find any bootstrap loaders. These are small programs located on your hard drive’s Master Boot Record (Basically the first sector of the first cylinder… Different for flash memory) This loads your operating system (Such as Windows/Linux) into memory. This makes it so that the operating system can quickly be referenced, rather than having to reference it from a slow hard drive.

Once the small program (bootstrap loader) completes its work, it turns over control of the PC to the operating system. Then, the user is ready to use the computer.


Q:

How reliable is this website? As in, what sources are used in writing articles. Also, are all sources cited?

Anonymous

A:

Not related to technology, but I’ll make an exception.

You ask if this website is reliable. I do my best to make sure all the information on this website is reliable and contains true fact. I can guarantee that all of the self experience articles (Such as tutorials) are completely true (Except for some occasional errors in code). However, for news topics opinions can vary, and knowledge can change.

As for the sources I use, almost all of the articles are written with my own knowledge. I cite images used from other sources when necessary, and sometimes use reliable sources for external data. When information from other websites is used, I will always provide the correct link to it.


Well, that seems to be all for this week. Huge thanks to everyone who submitted questions, and if you missed out on the opportunity to submit one this week, you can always submit one for next week. I really like learning what aspects of technology my audience is interested about, so keep the questions coming!

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