This document discusses GPS systems and how they work. It begins with defining GPS as the Global Positioning System, which uses satellites and radio signals to pinpoint a receiver's location anywhere in the world. It then discusses where GPS is used, including for military and civilian navigation, and how GPS works by measuring distances to multiple satellites. The document also provides details on GPS satellite locations and movements, the radio frequencies used, and how GPS receivers use timing data from satellites to triangulate their position. It concludes with an example of a GPS circuit using a PIC microcontroller.

1. GPS Systems
M.Emin Özgünsür
07070001052
Yasar University
May, 2011

2. AgendaAgenda
• What is the GPS ?
• Where is the GPS Using Places ?
• How is a GPS Working ?
• How is a GPS Circuit Working ?
• An Example of GPS Systems...

3. What is the GPS ?What is the GPS ?
GPS is mean that Global Positioning System. Shortly GPS, a special radio
receiver measures the distance from your location to satellites that orbit
the earth broadcasting radio signals. GPS can pinpoint your position
anywhere in the world.
GPS is becoming from 21 satellites real-time using and 3 satellites are
stand for back-up, totally 24 active satellites. GPS satellites send instantly
coded informations which hosted locations and distances informations
with radio waves to earth. Satellites turn around the world daily 12 hours.
By the 1960s, several rudimentary satellite positioning systems existed.
The U.S. Army, Navy, and Air Force were all working on independent
versions of radio navigation systems that could provide accurate
positioning and all weather, 24-hour coverage. In 1973, the Air Force was
selected as the lead organization to consolidate all the military satellite
navigation efforts into a single program. This evolved into the NAVSTAR
(Navigation Satellite Timing and Ranging) Global Positioning System,
which is the official name for the United States’ GPS program.

4. Where is the GPS Using Places ?Where is the GPS Using Places ?
Military Using Places
• Sea, Field and Air Vehicles Navigations,
• For finding targets,
• Search and Resque Operations,
• INS Systems Supports ( Tomahawk ),
• Plane strokes for badly wheathes, fogs,
etc.
Civilian Using Places
• Sea, Field and Air Vehicles Navigations,
• Geodesy and Geodinamic Measures,
• Kinematic GPS-Aided Photogrammetric Work,
• Local and Global Strain Measurements,
• Vehicle Tracking Systems,
• Aircraft, Weather Conditions, Contact,
• Your Limited or no Landing and Takeoff,
• Active Control Networks,
• Development Of GIS Databases,
• Tourism, Agriculture, Hydrographic Surveying
D4
D3
D2D1
General GPS Properties
• Global coating,
• Continuing to work in all
weather conditions and,
Dynamic platform compliance,
• Unlimited user facility,
• High accuracy, respectively.

5. How is a GPS Working ?How is a GPS Working ?
GPS Satellites Locations and
Movement on the Orbit
(Parkinson, 1996)
Satellities are being approximately 20,200 km
from earth (in the center of the 26,500 km) away
and take 11hours and 58 minutes to make a full
rotation.
Observed in any other place on earth and also
the number of at least 4 types of satellite and
each satellite is approximately 5 hours on the
horizon line.
GPS systems use, short-wavelength ( high
frequency ) radio waves. The GPS measures
from the satellites, datas flows provided by
electromagnetic waves to users.
Each GPS satellite location for the purpose of determining is whether they have
two basic L1 and L2 frequency. L1 and L2 frequencies of the fundamental
frequency of 10.23 MHz has been achieved by taking 154 and 120 full-folding, L1
frequency is 1575.42 MHz, the wave length of 19 cm. and the L2 frequency is
1227.60MHz wavelength is 24cm. Satellites, publish with their location
information (ephemeris) in the signals phase and code measurements.

6. How is a GPS Working ?How is a GPS Working ?
Two on the L1 carrier frequency is modulated PRN code and navigation
message data. L1 carrier frequency on the C / A code (Coarse / Acquisition), the
P-code (Precise /Protected Code), and navigation information to, the P code on
L2 carrier and navigation information to include.
Carrier wave
Code
Modulated
Carrier Wave
GPS receiver so that the passive nature of
committing in the air signal ( such as FM
radio ) does not send signals to satellites,
or in any other place.
GPS provides two different quality of
service: Standard Location Place Services
(SPS) and Precise Place Service (PPS).
SPS of them designated for civilian use, while PPS is used for military purposes.
For PPS, with access to a variety of properties inspected and limit the use of
encryption are carried. This mechanism is one of the AS (antispoofing), a type
of mixing (jamming) technique, deception (deception jamming) against either
measure.

7. How is a GPS Working ?How is a GPS Working ?
Directly to the location of a point on the earth (latitude, longitude, altitude, or the
X, Y, Z) determined that the absolute location (Point Positioning) is called. In
determining positions relative to each other by more than one location point
(Relative Positioning) is called.
The location is still to be determined point (triangulation, polygon, detail), static
positioning, moving in the (aircraft, ships, tanks), it is said without
specifying the kinematic location.
Aircraft, ships and other vehicles to navigate an instant (real time) position
determination can be made. Measures, to achieve more accurate results in
the evaluation of land in the office after measurements (post-processing) is
possible.
The unit's GPS receiver, the GPS satellite handoff area is between the two cases,
if the GPS receiver knows the distance between the satellites, the satellites can
find its position using the known positions. How much time we reached the
satellite radio signals by satellite to a distance determined by the calculation.
Satellite and receiver clocks are assumed to be synchronized. If there is an error
of 95% of this source of hardware, environment and atmosphere. Signal, signal
distortion may be deliberate reflection and counter-selective compliance.

8. How is a GPS Circuits Working ?How is a GPS Circuits Working ?
For information on the
GPS sample application u
sed isis circuit simulation,
and the source of two
PIC16F84,
bass. asm. hexcodes hav
e.

9. How is a GPS Circuits Working ?How is a GPS Circuits Working ?
Pin Diagrams CMOS Enhanced
FLASH/EEPROM Technology:
• Low power, high speed technology
• Fully static design
• Wide operating voltage range:
- Commercial: 2.0V to 5.5V
- Industrial: 2.0V to 5.5V
• Low power consumption:
- < 2 mA typical @ 5V, 4 MHz
- 15 mA typical @ 2V, 32 kHz
-< 0.5 mA typical standby current @ 2V
Peripheral Features:
-• 13 I/O pins with individual direction
control
-• High current sink/source for direct LED
drive
-- 25 mA sink max. per pin
-- 25 mA source max. per pin
-• TMR0: 8-bit timer/counter with 8-bit
-programmable prescaler

10. An Example o f GPS Systems...An Example o f GPS Systems...

11. ReferancesReferances
1) GPS for Dummies – Joel McNamara
2) GPS Theory, Algorithms and Applications - Guochang Xu
3) http://320volt.com/gps-hakkinda-ve-microchip-pic-serisi-ile-ornekler/

12. M.Emin Özgünsür
07070001052
muhammed.ozgunsur@student.yasar.edu.tr
07070001052@student.yasar.edu.tr
Yasar University
May, 2011