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The use of GPS provides one
of the best means we currently have for preserving the
locations of old abandoned graveyards.
WHAT IS IT?
The Global Positioning
System (GPS) is a satellite-based navigation system made
up of a network of 24 satellites placed into orbit by
the U.S. Department of Defense, orbiting
the earth about 12,000 miles above us. They are
constantly moving, making two complete orbits in less
than 24 hours. These satellites are travelling at speeds
of roughly 7,000 miles an hour. GPS satellites are
powered by solar energy. They have backup batteries
onboard to keep them running in the event of a solar
eclipse, when there's no solar power. Small rocket
boosters on each satellite keep them flying in the
correct path.
The satellite orbits are
calculated to provide continuous global coverage; with
all 24 satellites in operation, the necessary four
satellites are in view of a GPS receiver 100% of the
time. On average, eight satellites are present above the
horizon at any given time.
Because GPS satellites
can break down and their orbits are subject to drift,
the Global Positioning System also includes a set of
ground stations around the earth that monitor the
satellites' operation and location. The ground stations
relay information to a master ground station, which then
sends updated information back to the satellites so that
they can send more accurate signals to GPS receivers on
earth.
GPS works in any weather
conditions, anywhere in the world, 24 hours a day. The
full constellation of 24 satellites was achieved in
1994. Each satellite weighs approximately 2,000 pounds
and is about 17 feet across with the solar panels
extended. transmitted power is less than 50 watts and
they are built to last about 10 years. Replacements are
constantly being built and launched into orbit.
There are no
subscription fees or setup charges to use GPS.
The following websites
offer
THE HISTORY OF GPS
The United States
Department of Defense began work on the current GPS
system early in the 1970's, when satellite technology
made it feasible to provide the military with continous
global coverage. The first GPS satellite was launched in
1978, and the system was declared fully operational in
July of 1995. ln the 1980s, the government made the
system available for civilian use. GPS works in any
weather conditions, anywhere in the world, 24 hours a
day.
The Global Positioning System reached
Full Operational Capability (FOC) on July 17, 1995.
In 1996 the National
Security Council published the following goals for the
GPS system:
- To strengthen and
maintain national security.
- To encourage
acceptance and integration of GPS into peaceful
civil, commercial and scientific applications
worldwide.
- To encourage private
sector investment in and use of U.S. GPS
technologies and services.
- To promote safety
and efficiency in transportation and other fields.
- To promote
international cooperation in using GPS for peaceful
purposes.
- To advance U.S.
scientific and technical capabilities.
On March 29, 1996, a
Presidential Decision Directive (PDD) was signed by
President Clinton that described GPS as an international
information utility. The PDD included the following
directives:
- The U.S. government
will continue to operate, maintain and provide basic
GPS signals worldwide, free of direct user fees.
- The U.S. will
advocate the acceptance of GPS and it's
augmentations as a standard for use by initiating
international discussions and agreement with Japan
and Europe.
Read the full
Statement by President Clinton Regarding the United
States' Decision to Stop Degrading GPS Accuracy.
The United States
government permits worldwide, continuous access to GPS
signals, free of charge. And, since the GPS system
became operational in 1995, the development of "civil,
commercial and scientific applications" has proceeded at
breakneck speed. The development of these applications
in 2000 and beyond will be particularly exciting because
the United States government has abandoned its policy of
"Selective Availability." Under this policy, civilian
users of GPS could only pinpoint their location to
within about 100 meters (330 feet). As of May, 2000,
however, civilian users can obtain the same accuracy as
military GPS users. This means that all GPS applications
will be able to pinpoint a location to within 20 meters
(66 feet).
A full history of the GPS
system can be found at the GPS History, Chronology &
Budgets website located at
http://www.rand.org/publications/MR/MR614/MR614.appb.pdf
(PDF)
HOW GPS OPERATES
GPS satellites circle the
earth twice a day in a very precise orbit and transmit
signal information to earth. GPS receivers take this
information and use triangulation to calculate the
user's exact location by the use of longitude and
latitude information. Essentially, the GPS receiver
compares the time a signal was transmitted by a
satellite with the time it was received. The time
difference tells the GPS receiver how far away the
satellite is. Now, with measurements from a few more
satellites, the receiver can determine the user's
position and display it on the unit's electronic map.
Today's GPS receivers are extremely accurate, and they
maintain strong locks, even in dense foliage or urban
settings with tall buildings. Certain atmospheric
factors and other sources of error can affect the
accuracy of GPS receivers. GARMIN GPS receivers are
accurate to within 15 meters on average. It should also
be noted that the military places a random error in the
signals so that civilian units are not as exact in
pinpointing locations as the military units.
Latitude is
measured as distance from the equator, given in degrees.
Think of these latitude degrees or lines as "tomato
slices" of the globe. The equator is assigned the value
of 0o (read as "zero degrees") latitude. The
north pole is assigned the value of 90o North
latitude while the south pole sits at 90o
South latitude. These north and south pole values
establish the extreme limits of latitude.
Latitude has
been used in establishing U.S. state boundaries. For
example, the line that forms the southern border of
Tennessee is the 35o North latitude line,
Kansas' northern border is the 40o North
latitude line, and Wyoming's northern border is the 45o
North latitude line--or half the distance between the
equator and the north pole.
North
latitude is also commonly referred to with a positive
value while latitudes south of the equator are often
referred with a negative value. Thus the city of New
Orleans, Louisiana, could be approximated at 30o
North latitude or simply + 30o latitude while
the city of Durban in South Africa far south of the
equator could be approximated at 30o South
latitude or simply -30o latitude.
Longitude is
measured as distance east or west from an imaginary line
drawn from the north pole to the south through
Greenwich, England (the home of the person who made up
the system of longitude), given in degrees. Think of
these degrees or lines like "orange quarters" of the
globe. There are 180o (read as "one hundred
eighty degrees") in either direction--east or west--of
the line through Greenwich. At 180o the east
and west longitude lines merge in the Pacific Ocean,
forming another well-known line called the international
date line.
Longitude
lines have also been used in establishing U.S. state
boundaries. For example, the western border of Nevada
north of Carson City is the 120o West
longitude line. The 94o West longitude line
cuts right through Daviess County so all longitudes in
the county will be very close to 94o West
longitude.
Like
latitude, longitude can be referred to with a positive
or negative value instead of east or west. If longitude
is positive, it is a place east of Greenwich; if
longitude is negative, it is a place west of Greenwich.
Therefore, all longitudes in the U.S. are west, or
negative, longitudes.
By
converging a latitude line (a horizonal line) with a
longitude line (a vertical line), a unique and precise
spot on the globe is located. Both latitudes and
longitudes are further broken down into minutes and
seconds. Each degree has from 0 to a maximum of 59
minutes and each minute has from 0 to a maximum of 59
seconds.
Some use UTM
(Universal Transverse
Mercator) readings which is a grid coordinate system
that gives you a
position in specific zones. The GPS Device is a machine
that sends and receives signals to and from the
satellites in an effort to determine your current
position. GPS devices were long used by boats and
airplanes, but the technology has become so affordable,
that consumers can now buy them for personal use.
For
Additional Information, please visit the following
online GPS Tutorials:
CEMETERY
APPLICATIONS
The application of the
GPS to a cemetery appears to be somewhat unique, though
it differs very little from other consumer applications.
By using a GPS device, you can stand in the middle of a
cemetery, and it will determine the latitude and
longitude coordinates, and even altitude if it has
enough satellites tracked. It can store
up to 500 locations
in memory so that you can
refer back to it later on.
A sample listing for the
Crosier Cemetery located in South Harbor, Minnesota
would look like this:
Global
Positioning System (GPS) Latitude/Longitude:
46.07889 / -93.65333
Map Coordinates
042/26/32/SENW
A good example of the use
of determining the boundaries of a cemetery can be found
at the Jewish Cemetery in Rozhnyatov website
located at:
http://www.shtetlinks.jewishgen.org/Rozhnyatov/RozhCemetery.html
The following sample
taken from the
Kitterman Cemetery located in Section 15, Dahlonega
Township, Wapello County, Iowa is an example of the use
of GPS coordinates for a individual gravesite:
KITTERMAN,
Samuel J.
1874 - 1968
Husband of Annie Pearl
Note: Annie and Samuel J.: same
stone
GPS: 41° 02' 31" N 92° 20'
34" W
To see how GPS works go
to the following link for "Gibson County Indiana
Cemeteries" page
and click on "Locate
It On A Map" at the top of the page:
http://www.usroots.com/~jmurphy/gibson/gibcem/mon_ioof_owensville.htm
This takes you to a Tiger Map
Server map that shows the location along with
roads and the nearby
towns. Note that on this map several
cemeteries are
shown.
Or you can go to Topozone and
enter coordinates in degrees and decimal
degrees here:
http://www.topozone.com/finddd.asp
Type in the latitude coordinates
38.25300 and longitude coordinates of -87.68000 (don't
leave out the minus - sign, it tells the map which side
of
the prime meridian you are
on) This will take you to the same location,
only on a topo map
that shows terrain features. The same map will work
with UTM coordinates,
just click on UTM in the upper left corner, which
takes you here:
http://www.topozone.com/findutm.asp
Enter 16 for the UTM zone, 440501
for the easting, and 4233898 for the
northing.
Once you have this
location for a grave or a cemetery, anyone can find it
on a map. You can
purchase a good GPS unit for between $100 to $200
dollars, some
units will cost more. Your
local Dept.store such as Wal mart, Target, or Meijers
will have them in the Sporting
Goods section. The
lower-end models will use a compass pointer to show you
which way to go, along with the distance, your current
traveling speed, and estimated time of arrival.
Higher-end models include mapping data to provide a
street map. Most all GPS devices will update its
information every second.
ADDITIONAL
INFORMATION
Additional information on
this subject can be found at:
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