The document discusses the Global Positioning System (GPS). GPS is a satellite-based navigation system that determines precise position and time using radio signals from satellites. It is comprised of three segments - the space segment of satellites in orbit, the ground segment of control and monitoring stations, and the user segment of receiver equipment. The space segment consists of 24 satellites in six orbital planes. The ground segment tracks and maintains the satellites and calculates their orbits. The user segment performs navigation and timing functions using GPS receivers, which can be categorized based on their capabilities.

1. GLOBAL POSITONING SYSTEM

2. INRODUCTION
• Navigation is defined as the science of getting a craft or person from one place to another.
Each of us conducts some form of navigation in our daily lives. Driving to work or walking to
a place requires that we employ fundamental navigation skills. For most of us, these skills
require utilizing our eyes, common sense, and landmarks. However, in some cases where a
more accurate knowledge of our position, intended course, or transit time to a desired
destination is required, navigation aids other than landmarks are used.
• The Global Positioning System (GPS) is a satellite-based navigation and surveying system for
determination of precise position and time, using radio signals from the satellites, in real-
time or in post-processing mode

3. GPS SYSTEM SEGMENTS
• GPS is comprised of three segments:
• Satellite constellation
• The satellite constellation is the set of satellites in orbit that provide the ranging signals and data
messages to the user equipment
• Its also called Space segment
• Ground-control/monitoring network
• The control segment (CS) tracks and maintains the satellites in space
• Its also called Ground segment
• User receiving equipment
• The user receiver equipment performs the navigation, timing, or other related functions
• Its also called User segment

4. SPACE SEGMENT
• 12 Hourly orbits
— In view for 4-5 hours
• Designed to last 7.5 years
• Different Classifications
- Block 1, 2, 2A, 2R & 2F
• 24 Satellites
 4 satellites in 6 Orbital
Planes inclined at 55 Degrees
• 20200 Km above the Earth Orbits

5. CONTROL SEGMENT
Master Control Station
 Responsible for collecting tracking data from the monitoring stations
and calculating satellite orbits and clock parameters
5 Monitoring Stations
Responsible for measuring pseudo range data. This orbital tracking
network is used to determine the broadcast ephemeris and satellite
clock modeling
Ground Control Stations
Responsible for upload of information to the satellites

6. USER SEGMENT
 The most visible segment
 GPS receivers are found in
many locations and
applications

7. GPS RECIEVERS
• Receivers are generally categorized by their physical characteristics, the elements of the GPS signal they
can use with advantage, and by the claims about their accuracy. There are receivers that use only the
C/A code on the L1 frequency and receivers that cross-correlate with the P(Y) There are L1 carrier phase
tracking receivers, dual-frequency and multi-frequency carrier phase tracking receivers, receivers that
track all in view, and GPS/GNSS receivers. The more aspects of the GPS signal a receiver can employ, the
greater its flexibility, but so, too, the greater its cost. It is important to understand receiver capabilities
and limitations to ensure that the systematic capability of a receiver is matched to the required outcome
of a project. it is possible to divide receivers into three categories. They are; Recreation, Mapping, and
Surveying.