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GPS SystemsM.Emin Özgünsür
07070001052
Yasar UniversityMay, 2011
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...
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.
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
D3D2D1
General GPS Properties• Global coating,• Continuing to work in all weather conditions and, Dynamic platform compliance,• Unlimited user facility,• High accuracy, respectively.
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.
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.
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.
How is a GPS Circuits Working ? How is a GPS Circuits Working ?
For information on the GPS sample application used isis circuit simulation, and the source of two PIC16F84, bass. asm. hexcodes have.
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
An Example o f GPS Systems... An Example o f GPS Systems...
ReferancesReferances
1) GPS for Dummies – Joel McNamara2) GPS Theory, Algorithms and Applications - Guochang Xu3) http://320volt.com/gps-hakkinda-ve-microchip-pic-serisi-ile-ornekler/
