Global Positioning Systems

How it Works, 2D vs 3D, and Social and Ethical Concerns

How It Works:

  1. The satellites, once launched, orbit in space around the globe.
  2. The gps receiver sends out a radio wave to three or more satellites, and measures the distance to each by recording the time taken to reach each satellite.
  3. The receiver measures the distance to each satellite by recording the time taken to reach each satellite.
  4. The distance to each is a radius that the gps receiver is located on somewhere.
  5. By overlapping three, the point of intersection is the precise location of the GPS receiver.
  6. To make this more user friendly, the location is then displayed on a map installed into the GPS receiver.

2D vs. 3D

2D:

  • uses a circle based on a given radius, determined by how far away the satellite is from the receiver
  • the point of intersection of three or more circles will give a precise location of the receiver on a two dimensional plane.
  • only works on one plane--longitude and latitude

3D:

  • uses a globe shape based on a given radius, determined by how far away the satellite is from the receiver
  • the point of intersection of three or more globes will give a precise location of where on the globe the receiver is located.
  • work on multiple planes--longitude and latitude and depth

Social And Ethical Concerns

  • Security: GPS receivers can easily be hacked, and locations stored such as the owners home can be discovered.
  • Privacy: GPS receivers are track-able by others, including the government. (example- find my iPhone). Also, satellites store the location of GPS receivers on databases that show the current and past locations of the receiver.
  • Authenticity/Reliability: Maps on the receiver are not constantly updated, meaning as the landscape changes, data on the map may become incorrect
  • People and Machines: easier to use and more specific than a human description of a location. creates the concern for internet use in the car, as now these systems can access the internet to play Pandora, check Facebook, and answer incoming phone calls.

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