INTRODUCTIONGLOBAL POSITIONINGSYSTEM

BY-

RAMGIRWAR SWAPNIL

&

GADA HARSH,

M.E.S.C.O.E., Pune.

24 Satellite

constellation

Satellites orbit the

earth in 12 hrs.

6 orbital planes

inclined at 55

degrees with the

equator.

This constellation

provides 8 to 10

satellites from any

point on the earth.

What is GPS???

Satellites are located 12000 miles above

earth.

5 ground stations manage & monitor the

constellation.

It offers two types of levels of service :

1. SPS (Standard Positioning)

2. PPS (Precise Positioning)

Basis of GPS technology is precise

time & position information.

It is accomplished through atomic

clocks & location data.

HOW IT WORKS???GPS receiver receives these signals from three or more

satellites.

With this it determines the user position.

Firstly it measures time interval between transmission &

reception of satellite signals.

On the basis of this it calculates the distance between the

user & satellites.

For 2-D fix, 3 satellites & for 3-D fix 4 satellites are required.

ELEGANT CONVERGENCEDue its precise & stable

frequency signals its used as

synchronization sources for

various applications.

GPS was designed to

minimize its vulnerability

and make the satellites

extremely difficult to reach.

And its scope was

expanded to include civil

applications as well.

ACCURACY OF GPS

GPS receivers are accurate to within 15 meters.

Due to parallel multi channel design receivers are

extremely accurate.

12 parallel channel receivers lock onto the satellites.

These locks are maintained even in dense foliage and

urban buildings.

SATELLITE SYSTEM

SATELLITE SYSTEM

Satellites are traveling at speed of roughly 7000 miles per

hour.

They are powered by solar energy.

They have backup batteries onboard to keep them running in

the absence of solar power.

Small rocket boosters keep them flying in the correct path.

Ionosphere & troposphere

delays

Signal multipath

Receiver clock errors

Orbital errors

Satellite geometry

No. of satellites visible

SOURCES OF ERRORS

CONCLUSIONS

Applications of GPS are growing.

Cost of receivers is dropping & accuracy is

improving.

Thank You!