USE OF GPS METHODOLOGY IN CELLPHONE

Submitted to

Dr. Ahmed El-RabbanyProfessor of Geometrics Engineering Department of Civil Engineering

Ryerson University

Submitted by:Atique Ahmed ID # 989056528

Images courtesy ofUSDoD and writer

Overview GPS operations How does receiver work ? How does Cell Phone built-in GPS receiver

work? Cell Phones Methodology to use GPS Features of Cell Phones using GPS Conclusion Case Study

Objectives:

OVERVIEW GPS OPERATIONSOVERVIEW GPS OPERATIONSWhat does GPS ?What does GPS ?

GPS was originally intended for military applications, but in the 1980s, the US DoD made the system available for civilian use.

GPS works in any weather conditions, anywhere in the world, 24 hours a day.

There are three Satellite Navigation systems; GPS, GLONASS and GALILEO. I would reflect GPS only.

GPS was developed in the 1970s

GPS is satellite navigation system used to know specific location and time almost anywhere on the globe.

There are unlimited applications to use GPS. But I There are unlimited applications to use GPS. But I would elaborate following extent only:would elaborate following extent only:

If you buy 4G cell phone; GPS receiver is inclusively built-in with it.

If you buy a new car since 2009, GPS navigation system also included with it.

Latest still cameras have a built-in GPS features. When you take a photo it tells you the latitude and longitude of where you were and stamps that information on the photo.

APPLICATIONS OF GPSAPPLICATIONS OF GPS

Following are few features of GPS approach:Following are few features of GPS approach:

If radio frequency tag is attached to multi-story warehouse bin of items then its location can be precised using GPS system.

If employees card has radio frequency tag attached, he/she can be traced out during on or off duty.

In hospitals new born babies cannot be lost or abducted anymore due to GPS system.

APPLICATION’S FEATURESAPPLICATION’S FEATURES

HOW RECEIVERS WORK?HOW RECEIVERS WORK?

The GPS receiver and satellite generate the same pseudo-random code at exactly the same time. When the code arrives from the satellite, the time difference is compared to the same code generated by the receiver. This difference is multiplied by the speed of light 299,729,458 m/s (186,000 miles per second) to determine the distance to the satellite.(Note: Considering there is no GPS errors or biases interface)

HOW RECEIVERS WORK?....HOW RECEIVERS WORK?....

Pseudo-random code generated by receiver

Pseudo-random code generated by satellite

Time difference

Image courtesy to Nokia website

CALCULATION METHODOLGYCALCULATION METHODOLGY

Let suppose a driver travels from Toronto to Niagara Fall city, triangulation is a trigonometry function helps us to find the distance to a destination point using known angle and sides of a triangle.

Measures distance using law of Cosine

20100

?

Calculate the distance from A to B ( C ) using Law of Cosine

190

20000

Suppose a satellite (S ) is from 20100 KM away from a point A (Toronto) and 20000 KM from point B (Niagara Fall City).

B = Niagara falls

A = Toronto

S = Satellite

CALCULATION METHODOLGYCALCULATION METHODOLGY

By inserting the values in equation we find that C2 is equal to (20000)2 + (20100)2 – 2(20000)(20100) Cos(19deg).

Measures distance using law of Cosine

As Cellphone receiver does not measure angles, butthey calculate the time in which signal took to reach Cellphone receiver.

By simplifying, we calculated C2 is equal about 1,000KM or C = 100KM

This example helps us how to GPS on Cellphone determine the distance from one point to destination point.

USE OF TRILATERATIONUSE OF TRILATERATION

Trilateration is the method using measured distance from three satellites to cell phone receiver.

When the distances from three different satellites are obtained in Cellphone receiver then using trilateration method, position of the receiver can be measured.

HOW GPS RECEIVER WORKS?HOW GPS RECEIVER WORKS?

Using Trilateration Mythology

Intersection PointProviding location

HOW GPS RECEIVER WORKS?HOW GPS RECEIVER WORKS?

Understanding Errors and Biases

Light Refraction:Sometimes the GPS signal from the satellite doesn’t follow a straight line. Refraction is the bending of light as it travels through one media to another.

HOW GPS RECEIVER WORKS?HOW GPS RECEIVER WORKS?

Differential CorrectionDifferential correction is a technique that greatly increases the accuracy of the cellular collected GPS data. It involves correlation of Cell Phone receiver with base station - like Fido, Bell, or TELUS.

Satellite signals use L1 and L2 to communicate with cellular while Base Stations use CDMA - Code Division Multiple Access at 1900 MHz.

CELL PHONE METHODOLOGYCELL PHONE METHODOLOGYUSING GPSUSING GPS

Differential GPS SystemDifferential Global Positioning System (DGPS) is an improvement to Global Positioning System data received by cellular receiver.

Photo courtesy to Google

The Cellular Receiver correct their pseudoranges by synchronizing with base stations. The correction signal is typically broadcast over UHF radio modem.

Base Station-Tower

CELL PHONE USING GPS….CELL PHONE USING GPS….

Differential Correction

Cell phones & Service Provider:

User + Service Provider + Satellite Link

Images courtesy to Clip Art & iPhone

CELL PHONE USING GPS….CELL PHONE USING GPS….

4G Cell phones converts RF to digital signals

User + Service Provider + Satellite Link

Dig

ital Sig

nals

Service Provider Processor

RF

Images courtesy to clip art & iPhone

CELL PHONE USING GPS….CELL PHONE USING GPS….

Cellular system is very attractive to use in:

911 For emergency callsAVL Automatic Vehicle LocationRTK GPS Real Time Kinematic

Real Time Kinematic (RTK) is a technique used to measure carrier phase for GPS satellite navigation.

GPS and Cellular Integration

FEATURES OF CELL PHONE USING GPS

Methodology How GSP Traced PhonesMethodology How GSP Traced Phones

There are limitations where Satellite signals are not available for Cellular Phones.

RFID tags attached to every single phone facilitate to remain in contact with their B.S.

Using this technology, wireless network base station can locate precisely phones location always if its power is on.

The caller’s location can be further précised if the signal is received by minimum of three surrounding base stations.

FEATURES OF PHONE USING GPS….

CONCLUSIONCONCLUSIONA reference station (base station and tower) calculates differential corrections for its own location and time. Phones would remain in contact with their respective base stations up to 370 km (200 miles) from the station. However, some atmospheric errors and biases vary this space: specifically, satellite ephemeris errors and those introduced by ionospheric and tropospheric distortions. For this reason, the accuracy of DGPS may decreases with distance from the reference station.

Case StudyHow does iPhone work with GPS

Developer: Apple Inc.Manufacturer: Foxcom & PegatronModel 3G or 4GBuilt in GPS ReceiverCDMA Mode enableUMTS/OSM enableNetwork 2.4 GHz at 802.11 b/g/nGPS enable with A-GPS supportSimcard: MicroSIM card support CPU – A4 (ARM cortex-A8) dual coreRAM 512 KBStorage memory: 8-32 GBFrequency response: 20Hz to 20KHzPower Li-ion battery 3.7VSoftware iOS 4.3.1 CDMAApplication: Google Maps and Digital compass

Useful Acronyms using iPhoneUseful Acronyms using iPhone

CDMA = Code Division Multiple AccessUMTS = Universal Mobile Telecommunication System (Terrestrial Radio Access Network)GSM = Global System for Mobile-communicationiOS = iPhone Operating SystemCPU = Central Processing Unit (ARM-Cortex – A8)RAM = Random Access Memory

iOS- iPhone Operating SystemiOS is derived from Mac OS X, with which it shares the Darwin foundation, and is therefore a Unix-like operating system by nature.

iOS front panel has 18 gestures ready to useiOS capable to run 300,000 Applications

Can be download using iTunesGPS point of viewiOS is compatible with:Google MappingGoogle searchRadio Frequency – 850 – 1900 MHz

Can Synchronize L1, L2 and L5L1 (1575.42 MHz)L2 (1275.50 MHz)L5 (1176.45 MHz)

Networking: 2.4 GHzSMS: Compatible with MSOSQuad-band = UMTS/HSDPA/HSUPA/CDMA

Image courtesy to iPhone

Questions?

Thanks for Your Attention