Brief History of GPS
How GPS Works:
http://www.youtube.com/user/airforcespacecommand#p/u/38/fpPwMu3foGg
What is GPS?
The Global Positioning System (GPS) is a global navigation satellite system that provides location and time information in all weather, anywhere on the Earth where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government at the Air Force Base in Colorado Springs, Colorado and is freely accessed by anyone with a GPS receiver. The GPS project was started in 1973 to overcome the limitations of previous navigation systems. It was created and realized by the United States Department of Defense and became fully operational in 1994 (http://www.gps.gov).
How can we use GPS?
A GPS receiver picks up the GPS satellite system and calculates its position by precisely timing the signals sent by GPS satellites high above the Earth in space. Each satellite is constantly transmitting message that include the time the message was transmitted, the precise orbital information, and the general system health and rough orbits of all GPS satellites. The receiver will decode these messages from the satellite to determine the transit time of each message and the distance to each satellite. These distances along with the satellites’ locations are used with the aid of trilateration (the process of determining absolute or relative locations of points by measurement of distances, using the geometry of spheres) to compute the position of the receiver with an error only being +/- 1 meter. This position is then usually displayed on the GPS receiver or hand held unit, with a moving map to show you your position and can even tell you your elevation (http://www.gps.gov).
GPS and the Environment
Data collection systems provide decision makers with descriptive information and accurate positional data about items that are spread across many kilometers of terrain. By connecting position information with other types of data, it is possible to analyze many environmental problems from a new perspective. Position data collected through GPS can be imported into geographic information system (GIS) software or Google Earth, allowing spatial aspects to be analyzed with other information to create a far more complete understanding of a particular situation than might be possible through conventional means (http://www.gps.gov).
Environmental Benefits
- GPS data collection systems complemented with GIS packages provides a way for a comprehensive analysis of environmental concerns.
- Environmental patterns and trends can be usefully recognized with GPS/GIS data collection systems, and maps can be easily created.
- GPS data can be quickly analyzed
- Accurate tracking of environmental disasters such as fires and oil spills can be conducted more efficiently.
- Precise positional data from GPS can assist scientists in crustal and seismic monitoring.
- Monitoring and preservation of endangered species can be facilitated through GPS tracking and mapping.
racking and mapping.
Location/Navigation
GPS can be used to find and precisely record locations of objects of organisms.
In the ‘real world’: GPS is used for navigation more and more frequently. Shuttles, buses, taxis and other aspects of the transportation industry use GPS universally. Emergency service vehicles are equipped with GPS to help their operators quickly locate where they’re needed. More and more cars are equipped with GPS for navigation, and GPS has become an essential aspect of our mobile phones. Hikers and other outdoor enthusiasts use GPS to navigate or locate a specific features, and fishermen or scuba divers might use GPS to find a ship wreck. ‘Geocaching’ is a modern outdoor activity growing in popularity. Participants use GPS units to find cached “treasures” sign a log book, and share their experiences with others (www.geocaching.com).
Scientists use GPS to record and to find data collection points. Often they do not have the resources to continually monitor their study subject and recruit volunteers from the public to help. Providing GPS locations ensures that the many people collecting data are consistently collecting it from the same location. For example, Seward Park, in Seatlle, WA, has a population of hemlock trees that are suffering from root disease. Researchers are attempting to monitor the population in order to protect it. Volunteers are given GPS units with the location of each tree stored in it, and a rubric to score tree health. By using the GPS units the scientist can recruit any person interested in helping, they do not need people with a large knowledge base of the park or the hemlock tree (http://scienceforcitizens.net/project/278/).
In the classroom there are many applications for the GPS location function as well. Students can use their own school grounds to familiarize themselves with marking waypoints and using the GPS unit to find them again, For the first part of the lesson, groups of students will hide one or more objects around the school and use GPS to mark the way point. Then groups will trade units with one another and use them to locate each other’s objects. This will familiarize them with the use of GPS for location and navigation
Students can also use GPS during any experimentation that asks them to collect data or make observations outdoors. Requiring students to record GPS locations in their lab reports will instill in them the need for accuracy and repeatability in scientific experimentation and observation. Teachers can provide examples of papers in scientific journals in which the authors do the same.
Tracking
GPS is used to track the location of objects or organisms.
In the ‘real world’ GPS tracking is a widely used tool. Emergency service providers often use GPS to track the location and arrival time of police cars, ambulances, and fire trucks. Everyday people can protect their cars from theft by installing GPS tracking devices; these are installed in other expensive equipment such a laptops as well. Nowadays a pet owner can even implant a GPS tracking device in their dog or cat to make sure they can always find it if it runs away.
One way in which scientists use GPS is to track individual animals or animal populations. Using this technology, they can track organism movement and location. In August of 2010, for example, a whale was trapped in a fishing net in Chesapeake Bay. Local scientists wanted to help the whale but could not approach it without endangering themselves, they needed to wait for the whale to tire. By attaching a GPS tracking device to the net, the scientists were able to keep track of the whale’s location even when he returned to the open sea. They were able to remove the net once the whale was less agitated, saving the whale by enabling it to see and eat again (http://gpstrackinginfo.com/gps-technology-saves-humpback-whale/804). When scientists track many organisms in the same population, they can measure population movement and migration. This might be done by attaching a GPS unit to the animal, or by asking scientists or volunteers to take GPS readings whenever they observe an animal. Data collected from GPS tracking has led to important discoveries for conservation and resource management.
In the classroom, tracking data can be used by students as a real-life application. There are many places on the web in which past GPS tracking data for real animal populations is available to educators. One such place is WhaleNet (www.whale.wheelock.edu) which has GPS tracking data and maps on various individual whales and whale populations. One lesson that could be completed in the classroom would use the data from “Rat”, a Right Whale. Students will be given a table for Rat’s movements and create a map of the whale’s movements (this can be done on a paper map or on an online GPS mapping program such as GPS Visualizer (www.gpsvisualizer.com) or Google Maps (maps.google.com). The students can then answer questions about how far the animal travels in a day, what depth it spends it’s time in, human activity in the area the whale frequents, and why might scientists need to know this data.
GPS Data for Rat the Right Whale
|
Sighting No. |
Date |
Time (EST) |
Latitude |
Longitude |
Sea State (Beaufort) |
Site Distance (NM) |
|
1 |
12/08/96 |
1140 |
30.50'N |
81.34'W |
4 |
0.8 |
|
3 |
12/11/96 |
1215 |
30.65'N |
81.35'W |
3 |
2.2 |
|
7 |
12/13/96 |
1031 |
30.25'N |
81.34'W |
2 |
0.5 |
|
21 |
01/06/97 |
1109 |
30.51'N |
81.27'W |
2 |
0.2 |
|
24 |
01/07/97 |
1049 |
30.43'N |
81.34W |
3 |
0.3 |
|
26 |
01/11/97 |
1421 |
30.75'N |
81.32'W |
2 |
2.4 |
|
35 |
01/16/97 |
0949 |
30.45'N |
81.38'W |
3 |
0.4 |
|
40 |
01/18/97 |
1535 |
30.25'N |
81.37'W |
4 |
0.4 |
|
42 |
01/19/97 |
1111 |
30.38'N |
81.30'W |
? |
? |
|
47 |
01/20/97 |
1206 |
30.62'N |
81.28'W |
2 |
0.4 |
|
65 |
02/02/97 |
0945 |
30.29'N |
81.19'W |
2 |
0.7 |
|
67 |
02/03/97 |
1254 |
30.41'N |
81.28'W |
1 |
1.2 |
|
72 |
02/04/97 |
1616 |
30.76'N |
81.28'W |
1 |
.07 |
Mapping Function
Real World Applications
Using the near pinpoint accuracy provided by the GPS, highly accurate surveying and mapping results can be rapidly obtained, thereby significantly reducing the amount of equipment and time that are normally required of other conventional surveying and mapping techniques. Today it is possible for a single surveyor to accomplish in one day what used to take weeks with an entire team. GPS is unaffected by rain, wind, or reduced sunlight, or other adverse weather conditions and is rapidly being adopted by professional surveyors and mapping personnel throughout the world.
GPS provides accurate three-dimensional positioning information for natural and artificial features that can be displayed on maps and models of everything in the world - mountains, rivers, forests, endangered animals, minerals and many other resources. GPS position information for these features serves as a prime input to GIS, that assemble, store, manipulate, and display geographically referenced information (www.gps.gov).
Here are some real life situations where people are interested in using GPS and GIS software: fire fighters may want to know the exact location of all the fire hydrants in the area, a trucking fleet may need to pinpoint all gas stations on a route that accept a specific type of fuel card, a biologist may want to know potential habitats that an endangered species could use, or even parents may want to track their child’s movements, something that has helped many an anxious parent rest easy (http://www.gps.gov)!
How to use in your classroom
Mr. Trimpe’s lesson on Mapping a Biological Refuge
Students will use GPS data to mark an observation spot in the refuge and record their observational data taken at three different times a year (fall, winter, and spring). This way the students can come back to the same exact spot each season and see the seasonal changes that take place with respect to plants, trees, and any wildlife.
Samples of Mapping Worksheets and other Classroom Activities:
http://sciencespot.net/Pages/classgpslsn.html
Further Research
Here's a video for other GPS uses in the classroom
Links to GPS Lesson Plans
http://sciencespot.net/Pages/classgpslsn.html
http://www.gis2gps.com/GPS/lessonplans/gpsplans.htm
Links to on how to relate GPS to the "Real World"
https://en.wikipedia.org/wiki/GNSS_applications