By, Pravandu Prakash Panchal, Electronics & Telecommunication Department, Terna Engineering College, Nerul (W)

AGENDA

1. Introduction to Mobile Tracking and Positioning 2. Mobile Telecommunication Network 3. Geolocation System Architecture 4. Positioning techniques

INTRODUCTIONMobile Phone Tracking is attaining the current position of a mobile phone, stationary or moving. Mobile Positioning includes location based service that discloses the actual coordinates of a mobile phone bearer, used to locate a mobile phone, and thereby also its user (bearer), temporarily resides.

Need for Mobile Tracking and Positioning Intelligent transport system services Emergency services for subscriber safety Cellular fraud detection

MOBILE TELECOMMUNICATION NETWORKPSTN Total Service Area is divided into Cells; each ISDN with its own Base Station Mobile Switching Center

Base Station Controllers

BTS -1 (Base Transreceiver Station)

BTS - 2

BTS - 3

GEOLOCATION SYSTEM ARCHITECTURESubscriber Service Location Control desiring to track a Provider Center mobile device With past info about Sends MS; MSC commands a query Requests BTS BTS to requesting ID, particular BSCsID, TOA, RSS,MS Desired MSs TOA, MS dataRSS etc. Wireless coordinates search for MS inCoordinates the Location Network network Information Architecture BTS Requests response

MS Response data

PRINCIPLES OF MOBILE TRACKING AND POSITIONING1.

Measure the power levels of received signal from mobile. Mobile always communicates wirelessly with one of the closest base stations.

2.

3.

Base station coordinates are known.Mobiles location coordinates are nearby the base station.

4.

METHODS OF MOBILE TRACKING AND POSITIONING1.

Network Baseda) b)

Direction Based Distance Based

2.

Handset Based ( GPS )

3.

SIM BasedHybrid (Assisted GPS)

4.

ANGLE OF ARRIVAL (AOA) METHODFixed Reference Direction

1

2Angle of arrival calculated by multiple BTSs with respect to a reference axis

3

DISTANCE BASED POSITIONING TECHNIQUE

GLOBAL POSITIONING SYSTEM (GPS)GPS is a space-based radio positioning system that provides 24*7 three-dimensional positions, velocity and time information to suitably equipped users anywhere on or near the surface of the earth and sometimes off the earth.

HYBRID POSITIONING TECHNOLOGYAssisted GPS (A-GPS) is a system that can improve the startup performance, or time-to-first-fix (TTFF), of a GPS satellite-based positioning system. A-GPS has reference GPS receiver which keeps tracking the visible satellites all the time and the information are passed to the server to process. The server generates the assisted data and sent it to the mobile station through the data link whenever the user needs it.

The benefits of A-GPS include Time to First Fix (TTFF) improvement, higher signal sensitivity and maximum availability.

Geolocation TechniqueMobile Centric Based on GPS

CoverageNo indoor coverage

Accuracy

Delay

Others1. Requires GPS enabled handsets 2. Privacy user controlled 1. BSs need to be changed but no change to handsets 2. Privacy Network controlled 1.Changes in BSs but no change to handsets 2.Privacy - Network

Network Centric AOA

Good in outdoor areas

Good in rural & Long time to first open areas but fix poor in urban and indoor areas Poor Low

Network Centric TOA/TDOA

Good

Medium

Assisted GPS

Good

Superior

Low to high; depending on how many samples need to be transmitted Short time to fix

1.Both handset and network changes required 2. Privacy - partly user controlled