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National Geodetic Survey Quiz Show Questions |
| What do the letters in GPS stand for? | Global Positioning System |
| Who defines the official shoreline of the United States? | The National Geodetic Survey of NOAA. |
| What does GPS do? | Tells you where you are. Gives users their approximate position. Lots of uses for GPS in safety and navigation for ships, planes, trains, cars and hikers. |
| Why is shoreline so important? | For safe navigation and property ownership. |
| How good a job does GPS do? | Small GPS can tell you your location to about 100 ft (the infield of a baseball diamond). With a little more work and equipment, you can know your location to about 10 ft (a car). With more work, you can know where you are to about 1 cm (person's fingernail). |
| How is the shoreline determined? | From aerial photography (photogrammetry). |
| Does GPS have other uses? | Yes! Telling time (time transfer), motion (velocity), and can be used to help with weather and space weather (estimating water vapor and ionosphere). |
| What is the name of the computer program you used to "draw" the shoreline? | SocetSet or Softcopy |
| GPS sounds like science fiction. When can I get my own GPS? | GPS systems are available and in common use now. Small GPS systems can be purchased in outdoor equipment, electronic and department stores. Soon, every car will have one. |
| Where is the NOAA airplane that collects the aerial photography working right now? | Hawaii (April/May 2000) |
| Basically, how does GPS work? | There are many (28 now) satellites in orbit around the Earth such that several can be "seen" at any instant from anywhere on the globe. These satellites broadcast a signal telling each satellite's location and the time the signal was sent. On the ground, a person has a receiver to gather and interpret the signals from the satellite, and also to keep track of time. The receiver takes the difference between the time it got the signal and the time it was sent and multiplies that difference by the speed that the signal travels (the speed of light). This gives a distance to the satellite. Knowing the location of several satellites (in practice, 4 or more) and the distances to those satellites gives a unique location, in other words, the receiver's location. |
| Aside from navigation and safety, does GPS have other uses? | Almost anything where you would need to know the location of an object can make use of GPS; particularly in cases where the location is some- what isolated from known reference points. Certainly, GPS can be used for surveying, like finding property lines or city boundaries, but also for similar tasks like mapping the right-of-way of a pipeline or road or waterway, or more special cases like following a trail to recording the location of a valuable or dangerous material or the nesting sites of birds. There are many scientific uses too. |
| What are some scientific uses of GPS? | As mentioned, GPS is being used to measure water vapor in the atmosphere, and to monitor the ionosphere. Most commonly, GPS is used to measure the motion of objects that move too slowly to measure with other tools. This includes things like the flow of a glacier, or the motion of a buoy or research ship in the ocean; the bulging of a volcano as magma flows into the mountain from below, the effects of an earthquake, or even the motion and shape of the continents themselves. |
