### Technical Forestry

```Technical Forestry
GPS and GIS Systems
Shawn Linder
7/29/02
Learning Objectives
• List and describe the components of a GPS
system.
• Learning how use the Garmin GPS system.
• List and Describe the components of a GIS
system.
• Learn how to use components of a GIS system.
• How GPS and GIS systems are used in forest
management.
Problem Statement
• What are the various components of GPS
and GIS systems?
K.Q. #1: What is a GPS?
• Global Positioning System
• GPS is funded by and controlled by the U.
S. Department of Defense (DOD). While
there are many thousands of civil users of
GPS world-wide, the system was designed
for and is operated by the U. S. military.
K.Q. #2: How does a GPS work?
• GPS provides specially coded satellite
signals that can be processed in a GPS
position, velocity and time.
• Four GPS satellite signals are used to
compute positions in three dimensions and
the time offset in the receiver clock.
K.Q. #3: What are vital segments
of a GPS?
• Space
• Control
• User
K.Q. #4: What are mechanisms
of the space segment?
• This segment consists of the GPS satellites. These
space vehicles (SVs) send radio signals from
space.
• The nominal GPS Operational Constellation
consists of 24 satellites that orbit the earth in 12
hours.
• There are often more than 24 operational satellites
as new ones are launched to replace older
satellites.
K.Q. #4: What are mechanisms of
the space segment? (Continued)
• There are six orbital planes (with nominally
four SVs in each), equally spaced (60
degrees apart), and inclined at about fiftyfive degrees with respect to the equatorial
plane.
• This constellation provides the user with
between five and eight SVs visible from any
point on the earth.
K.Q. #4: What are mechanisms of
the space segment? (Continued)
K.Q. #4: What are mechanisms of
the space segment? (Continued)
K.Q. #5: What are the mechanisms
of the control segment?
• The Control Segment consists of a system of
tracking stations located around the world.
• The Master Control facility is located at Schriever
Air Force Base (formerly Falcon AFB) in
• These monitor stations measure signals from the
SVs which are incorporated into orbital models for
each satellites.
• The models compute precise orbital data
(ephemeris) and SV clock corrections for each
satellite.
K.Q. #5: What are the mechanisms
of the control segment?
K.Q. #6: What are the
mechanisms of the user segment?
• The GPS User Segment consists of the GPS
• GPS receivers convert SV signals into position,
velocity, and time estimates.
• Four satellites are required to compute the four
dimensions of X, Y, Z (position) and Time.
time dissemination, and other research.
• Navigation in three dimensions is the primary
for aircraft, ships, ground vehicles, and for hand
carrying by individuals.
K.Q. #6: What are the
mechanisms of the user segment?
K.Q. #7: What are parts the
Garmin GPS 12?
K.Q. #8: What is GIS?
• Geographical Information System
• A system for capturing, storing, checking,
integrating, manipulating,
analyzing and displaying data which are
spatially referenced to the
Earth.
K.Q. #9: What kind of data does
GIS collect?
• Features
• Attributes
• Values
K.Q. #10: What are three data features
that can be mapped in GIS?
• Points- Single GPS coordinate.
• Lines- Collection of GPS positions which
are identified with the same object and
linked together to form a line.
• Area- Similar to the line feature, except
ends on the line are tied to each other to
form a closed area.
K.Q. #11: What are examples of
attributes that GIS collects?
•
•
•
•
Color
Size
Cost
Occupants
K.Q. #12: What are examples of
values collected in GIS?
•
•
•
•
Blue
3 Bedroom
\$118K
5
Credits
• Ridgewater College Ag Department, Global
Positioning Packet.
• United States Geological Survey, GIS
internet page,
http://www.usgs.gov/research/gis/title.html
```