Group12 - Revision history

GPS-12: /* Disassembly, Assembly, and Component Description */

2008-03-03T07:53:00Z

Disassembly, Assembly, and Component Description

GPS-12: /* Conclusion */

2008-03-03T06:22:25Z

Conclusion

GPS-12: /* Conclusion */

2008-03-03T06:21:59Z

Conclusion

GPS-12: /* References */

2008-03-03T02:48:26Z

References

GPS-12: /* Executive Summary */

2008-03-03T02:47:40Z

Executive Summary

GPS-12: /* Background: Science of GPS */

2008-03-03T02:46:25Z

Background: Science of GPS

GPS-12: /* Background: Science of GPS */

2008-03-03T02:45:53Z

Background: Science of GPS

GPS-12: /* Background: Science of GPS */

2008-03-03T02:45:28Z

Background: Science of GPS

GPS-12: /* Background: Science of GPS */

2008-03-03T02:44:54Z

Background: Science of GPS

GPS-12: /* Conclusion */

2008-03-03T01:09:15Z

Conclusion

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 [[Image:Step20.JPG|center|200px| ]]
 |}
+--[[User:GPS-12|GPS-12]] 02:53, 3 March 2008 (EST)hassane
-−
 ==Receiver Systems==

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 This GPS project tested and taught us a number of things. We learned about one of the "new" technologies in surveying, but we also learned its limitations. To start this project had us work in a Wiki. This was an interesting learning experience for many of us that have not done much with programming. Working within the confines of the Wiki helped with team work and giving all the group members a way to get credit for what they have done.  This component also makes it so we can reference this report in the future and it is safe from things such as hard drive failure or loss of ones PC.
-Once we started working with the GPS we found is was fairly simple to navigate and didn't take a long time to get the basic functions down. We went back after getting the basic uses down and read that there were more functions to use that made it easier to take readings and use the GPS for different things. Some of the things the GPS receiver could be used for include geocaching, bird watching, biking, managing GIS data, and much more!
+Once we started working with the GPS we found is was fairly simple to navigate and didn't take a long time to get the basic functions down. We went back after getting the basic uses down and read that there were more functions to use that made it easier to take readings and use the GPS for different things. Some of the things the GPS receiver could be used for include geocaching, bird watching, biking, managing GIS data, and much more.
 In terms of results, we did not have a specific assignment to report numbers on but chose to take measurements on what we had done in a previous lab so that we could calculate error. We found that these GPS units are very bad at reporting elevation and hardly work at all if you are surrounded by buildings. These devices work best in open fields so that they can pick up more satellites and get a better idea of location since there is very little to no interference. To get better readings in elevation you just need to pay up and get a better unit.  As a result our unit actually produced readings that were decreasing in elevation even as we were increasing in elevation.  This is fairly scary since so many people depend on these devices when they are lost.  Also, the device gave measurements with accuracy ranging from  +/-28ft to +/-46 ft.  28 is a large range, 46 just shows that the device has no clue what your elevation is and might as well use a random number generator.  What is worse was that even with these large ranges only one of our measured values was barley within the listed range.  On average, the values were off by 123.95 ft.  One can only hope that our machine was calibrated wrong or that this was caused by being in the city because with that kind of error this function should not be included.

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 This GPS project tested and taught us a number of things. We learned about one of the "new" technologies in surveying, but we also learned its limitations. To start this project had us work in a Wiki. This was an interesting learning experience for many of us that have not done much with programming. Working within the confines of the Wiki helped with team work and giving all the group members a way to get credit for what they have done.  This component also makes it so we can reference this report in the future and it is safe from things such as hard drive failure or loss of ones PC.
-Once we started working with the GPS we found is was fairly simple to navigate and didn't take a long time to get the basic functions down. We went back after getting the basic uses down and read that there were more functions to use that made it easier to take readings and use the GPS for different things. <<<<whoever has the manual should put in some of the functions here to expand this>>>>
+Once we started working with the GPS we found is was fairly simple to navigate and didn't take a long time to get the basic functions down. We went back after getting the basic uses down and read that there were more functions to use that made it easier to take readings and use the GPS for different things. Some of the things the GPS receiver could be used for include geocaching, bird watching, biking, managing GIS data, and much more!
 In terms of results, we did not have a specific assignment to report numbers on but chose to take measurements on what we had done in a previous lab so that we could calculate error. We found that these GPS units are very bad at reporting elevation and hardly work at all if you are surrounded by buildings. These devices work best in open fields so that they can pick up more satellites and get a better idea of location since there is very little to no interference. To get better readings in elevation you just need to pay up and get a better unit.  As a result our unit actually produced readings that were decreasing in elevation even as we were increasing in elevation.  This is fairly scary since so many people depend on these devices when they are lost.  Also, the device gave measurements with accuracy ranging from  +/-28ft to +/-46 ft.  28 is a large range, 46 just shows that the device has no clue what your elevation is and might as well use a random number generator.  What is worse was that even with these large ranges only one of our measured values was barley within the listed range.  On average, the values were off by 123.95 ft.  One can only hope that our machine was calibrated wrong or that this was caused by being in the city because with that kind of error this function should not be included.

← Older revision		Revision as of 02:48, 3 March 2008
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	http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=5325		http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=5325
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−	~~[http://www.apastyle.org/ APA Style]~~
−	~~You must use this format (It's easier than MLA, so don't worry).~~

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-[[Image:GPS S Orbit.png|right|400px|thumb|GPS Satellite Constellation]]
+[[Image:GPS S Orbit.png|right|350px|thumb|GPS Satellite Constellation]]
 This page provides a brief history and introduction to GPS (Global Positioning System) and the science behind it's ability to calculate various parameters on the earths surface. The GPS system, which was originally developed for defense purposes, has recently been utilized for a wide array of uses such as recreational activities and business purposes.
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 Conclusion to the GPS research project covers Group 12's experience with the Wiki page and the research behind the GPS calculation methods, functions, components and overall accuracy.  Further conclusions cover the attitudes and recommendations of the group members.
 ==Background: History of GPS ==

← Older revision		Revision as of 02:46, 3 March 2008
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	[[Image:GPS position determination.gif\|right\|400px\|thumb\|Example of 2D position determination with 3 satellites]]		[[Image:GPS position determination.gif\|right\|400px\|thumb\|Example of 2D position determination with 3 satellites]]
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	This is because there are four variables to solve for (x, y, z, and t); therefore, there must be a minimum of 4 satellites in contact with a GPS device. While the GPS device needs 4 satellites in order to function, there are far more than 4 satellites that a GPS device can receive data from at any one time. It depends on the location of the device, as well as the location of the satellites in orbit, but there are usually between 8-10 satellites in contact with a device at any one time. The image to the right shows how the line of sight between a GPS device and the GPS satellites changes with time. This allows for greater reliability and some greater accuracy in the system.		This is because there are four variables to solve for (x, y, z, and t); therefore, there must be a minimum of 4 satellites in contact with a GPS device. While the GPS device needs 4 satellites in order to function, there are far more than 4 satellites that a GPS device can receive data from at any one time. It depends on the location of the device, as well as the location of the satellites in orbit, but there are usually between 8-10 satellites in contact with a device at any one time. The image to the right shows how the line of sight between a GPS device and the GPS satellites changes with time. This allows for greater reliability and some greater accuracy in the system.

← Older revision		Revision as of 02:45, 3 March 2008
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	[[Image:GPS position determination.gif\|right\|400px\|thumb\|Example of 2D position determination with 3 satellites]]		[[Image:GPS position determination.gif\|right\|400px\|thumb\|Example of 2D position determination with 3 satellites]]
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−

	This is because there are four variables to solve for (x, y, z, and t); therefore, there must be a minimum of 4 satellites in contact with a GPS device. While the GPS device needs 4 satellites in order to function, there are far more than 4 satellites that a GPS device can receive data from at any one time. It depends on the location of the device, as well as the location of the satellites in orbit, but there are usually between 8-10 satellites in contact with a device at any one time. The image to the right shows how the line of sight between a GPS device and the GPS satellites changes with time. This allows for greater reliability and some greater accuracy in the system.		This is because there are four variables to solve for (x, y, z, and t); therefore, there must be a minimum of 4 satellites in contact with a GPS device. While the GPS device needs 4 satellites in order to function, there are far more than 4 satellites that a GPS device can receive data from at any one time. It depends on the location of the device, as well as the location of the satellites in orbit, but there are usually between 8-10 satellites in contact with a device at any one time. The image to the right shows how the line of sight between a GPS device and the GPS satellites changes with time. This allows for greater reliability and some greater accuracy in the system.

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 [[Image:GPS position determination.gif|right|400px|thumb|Example of 2D position determination with 3 satellites]]
-This is because there are four variables to solve for (x, y, z, and t); therefore, there must be a minimum of 4 satellites in contact with a GPS device.  While the GPS device needs 4 satellites in order to function, there are far more than 4 satellites that a GPS device can receives data from at any one time.  It depends on the location of the device, as well as the location of the satellites in orbit, but there are usually between 8-10 satellites in contact with a device at any one time.  The image to the right shows how the line of sight between a GPS device and the GPS satellites changes with time.  This allows for greater reliability and some greater accuracy in the system.
 To explain the process of locating an object within a set of spheres, image a 2-D plane in which a GPS device is finding its location using three imaginary spheres created by three different satellites around it.  The common intersection of the three spheres gives the location of the GPS unit.  This method of determining the location of the GPS unit based on spheres of known area is called trilateration.