mobile postioning system

7/31/2019 Mobile Postioning System

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Its a system which is used to provide location ofinformation of phone calls.

It give an exact solution for the threedimensional location of a mobile by using fourGPS satellite.

The accuracy of this system is 100 mtr.

In this system by the use of satellite we get thethree coordinates of mobile and after that


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we need one more software which can relate theoutput of this system with earth coordinate

system. So that we get the exact location i.e. inwhich city or in which street or house themobile is present.

Its is based on Global Positioning System.


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The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of

24 satellites placed into orbit.

GPS satellites circle the earth twice a day in a veryprecise orbit and transmit signal information to

earth.


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GPS receivers take this information and use

triangulation to calculate the user's exactlocation. Essentially, the GPS receiver comparesthe time a signal was transmitted by a satellitewith the time it was received.

The time difference tells the GPS receiver howfar away the satellite is. Now, with distance

measurements from a few more satellites, thereceiver can determine the user's position anddisplay it .


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Its based on complex mathematical calculations ofdata given by satellites.

By using three satellite we get three equations fromwhich we derive a circles and the intersection ofthese circles with the circle derived from fourth

equation with the help of fourth satellite gives theexact location of required mobile.


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Its based on TDOA technique i.e. Time

Difference of Arrival.

The distance between a mobile and a station isdetermined by measuring the time it takes for a

signal to reach the mobile from the station.

Multiplying the TDOA t by the signal velocity

c gives us the distance.


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The formula which is used to measure thedistance between two points is

Then we get such three equations from threesatellites.

The circles derived from these equations shouldbe intersect on the same point with the fourthcircle.

d = [(x2 - x1)2 + (y2 - y1 )

2 + (z2 - z1 )2]1/2


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If the four circles no longer intersect at thesame point, then the GPS system knows that

there is an error in it?s clock.

Then we have to remove this problem first, then

proceed further.

Behind the scenes, there are also many complex

calculations taking place which enable thesystem to compensate for atmosphericdistortion of the signals, but the principleremains same.


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Pinpoints exact locations.

Monitors employee driving habits andactivities, to avoid accident.

Its used in forecast the weather conditions, toavoid the drastic condition.

To monitor the position of several vehicles orpeople ,this can include children, criminals,police and emergency vehicles


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Weather:asatellite signal slows down as itpasses through inclement weather.

Buildings:signals are often reflected off tall

buildings before reaching the receiver, becausethe signal is delayed, information provided isinaccurate.

Time inaccuracy: when a GPS receiver's clockis not synchronized with the atomic clocks onthe satellites, timing errors will occur.


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Satellite visibility/clear path for satellites:

Buildings, electronic interference,canblock signal reception. This is anotherreason why GPS units usually cannotoperate underwater or underground.

Satellite position/geometry: satellites mustbe geometrically placed at wide angles

relative to one another for better reception.


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To locate the position of mobile.

As a tracking device to track any vehicle .

Have military applications in missiletechnologies.

To find out the smallest route between any twopoints.


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mobile postioning system

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