Global Positioning Systems
How it Works, 2D vs 3D, and Social and Ethical Concerns
How It Works:
- The satellites, once launched, orbit in space around the globe.
- 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.
- The receiver measures the distance to each satellite by recording the time taken to reach each satellite.
- The distance to each is a radius that the gps receiver is located on somewhere.
- By overlapping three, the point of intersection is the precise location of the GPS receiver.
- To make this more user friendly, the location is then displayed on a map installed into the GPS receiver.
2D vs. 3D
- 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
- 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.