Group5
Contents |
Executive Summary
This section is much like an abstract and summarizes the entire report
Introduction
The Global Positioning System (GPS) was created by the United States Defense Department in the 1970's by utilizing a satellite orbiting the Earth, which provides reliable positioning, navigation, and timing services available worldwide and free of charge. GPS provides accurate time, velocity and location information regardless of weather, time of day, or where in the world the GPS is being used from. The basic reading displayed on each individual GPS at any moment is the position, including longitude, latitude and elevation, the velocity, including the velocity north, east, and up, along with the time, in universal time coordinated, at any instant. The GPS is generally accurate to 10 meters positioning, 10 centimeters per second velocities, and less than 0.1 microsecond time. The GPS has the level of accuracy mentioned before because there are four satellites, guaranteed, available in space to obtain data from at any given time. Additionally, GPS's are equipped to give directions from where the individual GPS is located to any other place on earth, regardless of the method of transportation (ie: by land, water or air).
GPS-5 Group Members
- Jackie Bayer: Responsible for disassembly and reassembly of GPS
- Leah Courtney: Responsible for features of the GPS and current applications
- Jeffrey Dowgala: Responsible for disassembly and reassembly of GPS
- Lauren McNally: Responsible for current applications, brief history and future possibilities
- Austin Wong: Responsible for current applications, brief history and future possibilities
History
GPS began as a U.S. Department of Defense military research project in the 1970's. The original idea put forth by the USDOD was to attach atomic clocks on satellites orbiting the Earth and use the gathered data for navigational purposes. The first set of GPS satellites were launched in 1978, and second-generation satellites were then launched in 1989. By 1995, the satellites were fully functional, and used for military purposes, with limited, less accurate, use by common citizens. Because of a 1983 misinterpretation of data, in which case a more accurate GPS may have prevented Soviet interceptors shotting down a Korean Passenger Plane which mistakenly entered Soviet airspace areas, President Ronald Regan allowed the GPS system to be available worldwide free of charge. In 2004, President George W. Bush issued an updated policy to keep GPS free of direct charges.
Earthmate GPS PN-20 Pages
Satellites Page
The Satellites Page is the first page to appear when the Earthmate GPS PN-20 is turned on. This page summarizes the locations of the various GPS satellites while orbiting the earth, which the individual GPS's are obtaining data from. These satellites make it possible for the GPS system to obtain its various locational data. In addition, this page includes the current GPS status, the signal stength from the satellites, and the GPS accuracy.
Map Page
The Map Page is only available for use if a 2-D or 3-D fix is obtained. If obtained, the GPS can assemble a map of someone's current location with the avalible satellite data. An example of usage of this page includes driving a car, if you a desired location is indicated. Then, the map can be followed to get to the desired location. A few features include the direction of travel, speed of travel, estimated time of arrival to destination, where to turn, among others. Another feature of this page is the layering application which allows various maps to be avalible for any particular location. These maps include topographic data, satellite imagery, color aerial imagery, USGS Quads and high- resolution cities.
Compass Page
The Compass Page is a digitally expressed image of an ordinary hand-held needle floating compass. In contrast to a traditional needle floating compass, the GPS page can instruct the compass to point in the direction of a specific destination, instead of it only pointing North, as it traditionally does. If a specific destination is chosen for this page, the GPS will also include the distance and time until the next turn that needs to be taken while traveling.
Trip Info Page
The Trip Info Page can be used to track various components of each trip from start to finish. The screen is divided into eight sections: coordinates (latitude and longitude), trip odometer, trip moving time, trip stopped time, trip total time, current speed, maximum speed and average speed of the trip. This page may be customized by the user to only display certain sections, depending on what information the user finds to be most important.
Find Page
Lost? The Find Page can be used to search for and locate various positions such as addresses, roads, cities, points of interest, way-points, coordinates and more. There are two ways to seach on this page. First, there is the "Find Near Map Center", which can be used to locate destinations surrounding a current location, such as geographic features. Second, there is the "Find By Name", which can be used to locate specific locations, such as an address. This page also has a memory for past searches, which allows places previously searched for to be easily pulled up.
Way-points Page
A way-point is a marked location with specific coordinates. It is possible to mark a current location, or a searched location as a way-point by using the "Mark Button". After individual locations have been marked by the way-point page, it can be customized with a name, coordinates and comments. A symbol may be chosen for the way-point to express what the location represents. Symbols include a cave, church, dining area, house, post office, among others, which may be saved for later use. A list of saved way-points may be pulled up to obtain directions to them from any current location.
Routes Page
Various routes may be mapped out using the Routes Page, which include:
- From a current GPS location to a way-point
- From a current GPS location to a Find Search result
- Between two way-points
- Between two Find Search results
- Between a way-point and a Find Search result
Once a route is created, its direction can be followed to reach the desired destination.
Tracks Page
By defult, the Earthmate GPS PN-20 records & tracks the travel route taken until the recording of the trip is turned off. That is, a user may use the Tracks page it to retrace his or her steps after any distance into the trip. This feature may be helpful for backtracking when lost. Similarly, these tracks may be saved for future use.
Sun/Moon Page
The Sun/Moon Page is used to gain information about the sunrise and sunset or the moonrise and moonset. The GPS can display the times of these, as well as the moon phase for the current GPS location. The screen for the Sun/Moon Page will also display the current time and date, which allows the user to determine how much time until the next rise or set is supposed to occur.
Tide Page
The Tide Page can be used to display information on high and low tides based on a specific time, date and tide station.
Hunt/Fish Page
Convienient for hunters, the Hunt/Fish Page is used to predict if a certain day may be good or bad for hunting or fishing. This page can also predict the best times to hunt or fish for a current GPS location. It is also possible to pan the map to other locations nearby and see the hunting or fishing conditions for that area as well, which makes it easy to find optimum locations and times for hunting and fishing.
Device Setup Page
The Device Setup Page is used to modify default settings on the Earthmate GPS PN-20. Examples of settings that may be altered are battery type, color scheme, backlighting intensity and color contrast.
Current Applications
Basic Current Applications
In general, GPS's are found in everyday life, including in automobiles, aircrafts and ships. Furthermore, they are currently found in cell phones, watches and personal computers. GPS's are used for navigational, construction, surveying and scientific purposes, among others. For example, geologists use GPS's to measure volcanic expansion and fault line movements. Similarly, geographers use GPS's to define spacial relations between different features along the Earth's surface. Finally, GPS's have aided public officials in reducing the time it takes for ambulances, firefighters and police offers to arrive at emergent scenes.
GeoCaching
GeoCaching is easily described as a world wide treasure hunt game using GPS navigation. Geocachers hide little trinkets (caches), along with a log book in waterproof containers in various locations around the world. Typically, the caches are not of high value. Each geocacher uses their GPS to determine the coordinates of where they hide their cache, and then enters the coordinates on the geocaching website. Other geocachers then look up these coordination locations and search them out using their own GPS. Once found, the geocacher logs their findings in the log book and on the geocaching website. The geocacher is then free to leave the object there for the next geocacher to find, or they make take the "treasure" and replace it with another treasure of equal or better vaule. This worldwide game has attraced over 480,000 participants and added a fun twist on to the many uses of GPS systems.
Surverying
Although the GPS cannot replace the accuracy of hands-on field surveying, the maps avalible on GPS systems can be helpful in priliminary investigations of a plot of land to be surveyed. Also, once the land is surveryed, the data obtained can be uploaded to GPS systems to increase the accuracy of the land data.
Navigation
With the various pages and maps avalible on the Earthmate GPS PN-20, it can make it vitually impossible to get lost. Whether in a car looking for directions to a specific destination or outdoors hiking to find a specific landmark, the GPS system can help anyone find his or her way.
Military Use
Although the military in most situations would use more advanced systems of GPS than the Earthmate GPS PN-20, the same basic applications can be applied. GPS can be used for more accurate location targeting of missile launches, guiding troops who are traveling in unknown territories or in the dark and to enhance communication between air and ground troops.
911 Assistance
Being able to tell 911 exactly where the caller is in an emergency can be exteremly helpful, and in some cases, life saving. For example, this would be espically helpful for anyone injured or in danger out in the middle of woods, where there are no roads or signs to distinguish exact loactions. Being able to tell 911 the exact global position allows them to get to each emergency quicker.
Future Possibilities
Include future possibilities here.
Before Disassembly Section
The Earthmate GPS PN-20 was in new condition before the disassembly began. The GPS is composed of many elements, but the device was only disassembled down to about nine main parts. Numerous small resistors and capacitors are on the circuit board, and could not be taken off without destroying the equipment. The nine parts include the battery compartment, two double A batteries, memory card, back cover, internal battery, circuit board, keypad and seal, LCD screen, and front cover. In order for the GPS to work, the CD-ROM maps that come in the package with the device need to be loaded on to the memory card. Since group 5 only had one gigabyte of storage, only a few of the maps were put on the card. After the memory card has been inserted in the GPS, it can be used.
As previously stated, the GPS consists of many electronic elements such as resistors and capacitors. These are configured in such a way to make the device operate. The circuit board is the main component in the GPS, and all parts are connected here. Notably, there is a USB connection from the batteries to the circuit board and also from the screen to the circuit board, as seen during our disassembly. The user types information into the keypad, which is processed through the circuit board. The data on the memory card is read, and the circuit board sends a signal to the LCD screen after the information has been processed, which shows up for the user to read. The process is powered by the two double A batteries. More detail of the types of materials and how many parts are included can be found in the subsequent sections and photographs.
Disassembly Procedure
The disassembly took place on February 22, 2008 and is outlined below. The only tools used were small screwdrivers.
- 1. Take battery compartment off.
- 2. Take out memory card.
- 3. Unscrew screws on back cover.
- 4. Remove cover.
- 5. Take apart wires from USB connection to battery and internal battery.
- 6. Unscrew screws from circuit board.
- 7. Remove circuit board from the device.
- 8. Remove keypad and seal.
- 9. Snap off screen, but leave plugged in to circuit board.
Most of the disassembly was fairly easy. Steps one and two were especially easy because they need to be done on a regular basis by any user who owns the device. The memory card and batteries need to be replaced often. Taking the screws out was probably the hardest part in the disassembly because they were very tiny, particularly on the circuit board. Removing the wires from certain connections was also pretty easy. The removal of the keypad and seal was tricky because it was easy to tear. Once the screen was taken off, we had to pay special attention not to scratch it or get any marks on it. In general, however, the disassembly was simple.
After Disassembly
Part Table, including:
- Part number
- Part name
- Number of parts of this type
- Part material
- Part manufacturing process
- Image of the part
- CAD file for selected parts
Assembly
- Document each step to reassemble the product
- How difficult was each assembly step?
- What types of tools were required to perform this step?
After Assembly
- Does it still work?
- Conclusion remarks
References
[1] Global Positioning System: Serving the World
[2] Geocaching
[3] "Into to GPS"
[4] U.S. Updates GPS Technology
Guide to Writing Wiki Code
The beauty about Wiki is that if you don't know the code, you can steal it from someone's page that does. Feel free to click the "edit" links or tabs to view the code for sections or the pages respectively. Be weary about wrecking havoc on another's page. Each page can be rollbacked to a previous verison and your username is linked to all changes. Although you might think it's cool to go through and insert "MIKE RULES" throughout the page, I'm sure Dr. Lewis would not be pleased.
Here's a few tips on writing with Wiki:
This is a bracket "[" "]"
This is a brace "{" "}"
To create a new page/link within Wiki:
- Double brackets, page name, double brackets
- Typing in a new page name will automatically create a page, which when clicked, you can then edit.
- Whatever name you first type in is the name of the page. You can't change page names, only create new pages. Think before you create a new page.
- Don't worry about slashes or anything, all pages are located in the same directory. If I wanted to create a page called "MAE 277 Template" the code would be ''MAE 277 Template'' Note: Brackets are italicized to prevent creating a new page.
Your table of contents is created automatically.
- 1,2,3,4 are level 2 sections
- 1.1, 1.2, 1.3 are level 3 headers
To create headers:
- Section titles are wrapped with two equal signs ==My favorite header==
- Bold headers within a section are wrapped with three equal signs ===My not-so-favorite header===
Asterisks indicate bullets. Be sure to put each asterisk on a new line.
- Here's one
- Here's two *Here's three, but its not on the next line
Bold text:
- Start line with "b" in "<>". Be sure to end the line with "/b" in "<>" if you don't want the whole paragraph to be bold.
- Surround text to be bolded with three " ' " marks on either side. Or highlight the text and click the "B" button on the toolbar.
Italics:
- "i" in "<>". Don't forget to end with "/i" in "<>"
- Highlight the text and click the "I" button in the toolbar (It will put four " ' " on either side).
This is a broken link media file caption
Media tags are indicated by "Media:", images by "Image:" Broken links in red. Case is not important. Use the toolbar to get examples if you're not sure.
Spacing is werid in wiki.
Single return does nothing.
Double return (blank line), breaks the line.
Triple return (two blank lines), puts an extra blank line between lines of text.
"br" in "<>" will break lines. They can also be used to separate section headers.
Finally, use the "Show Preview" button on the bottom of the page to see how it looks before saving. It will allow you to catch and edit your errors without having to edit the page again. Just don't forget to save it when you're really done.
This is an example table
See help page for more information on the syntax.
| This is Column Header 1 | This is Column Header 2 | This is Column Header 3 |
|---|---|---|
| This starts Row 1 | Width values (pixels) in header are used to designate the width of the column for the entire table. Text will wrap but it helps to control the layout. Height of the row is determined by the row's largest content | A return and single vertical lines separate columns in rows. A double vertical line is necessary if you don't break up the text for cells. |
| This starts Row 2 | "br" in brackets break lines. Wiki sometimes ignores blank lines. |
Some html tags can be used, but not many. Notice the align equals center tag at the beginning of the row. It centers the text in the first two columns, but doesn't work for the third column. I don't know why. Adding the tag again to the beginning of the cell in question will center the text. |
| This starts Row 3 | Image tags are in this format:
|
 
|
| This starts Row 4 | Notice the repeating code for every row? It's important. A vertical line and a dash indicate the start of a new row. An exclamation point indicates the first column. You can put the entire row onto a single line, but it's easier to read if you break it up. Again, wiki usually ignores new paragraphs. | Make sure to end the table correctly (vertical line and closed brace). Not doing so might still display the table, but nothing that comes afterwards. |
