SKKU Embedded Software Lab. 23 1 Tizen Location Framework.

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SKKU Embedded Software Lab.

Tizen Location Framework

• Provides location based services(LBS)– Position information– Satellite information– GPS status

• Based on GeoClue• Features

– Hybrid positioning solution(GPS, WPS, SPS)– Get the current position, last known position, distance &

velocity– Get satellite information of GPS and GLONASS– Geo-fencing– Geocoding and reverse geocoding– Search POI(Point of interests), Calculate route

Introduction

Location Library

Location Framework Architecture

Application

GeoClue library

GPS Provider

GPS Plug-in

SPS Provider

WPS Provider

GeoClue providers

Telephony

Message Sensor libnetwork libxml2 libcurl libsoup

External ComponentsKernel

(UART)

GPS Receiver AGPS Server WPS Server

Map Service Server

Location componentLocation Plug-in

Open Source

GPS Plug-in

Kernel

Remote Server

• Support vendor specific device’s plugin by shared library

Location Components

5Location Use Cases

6How to Interact between Components

• Wi-Fi and Cell-ID based positioning– Provide fast and accurate

location to Wi-Fi capable devices in indoor and outdoor environment

• Standard Assisted GPS(SUPL)– Communication between SET and

SUPL server is transported over a secured IP connection

• Predicted GPS– Extends the validity of assistance

from 2-4 hours to 7 days. Assistance data is downloaded from a server

• Self Assisted GPS– Mobile GPS clients generate

assistance data without network connection

Positioning Technologies for Fast Position Fix

8Comparison of Positioning Technologies

• A software framework utilizing the D-Bus inter-process communication(IPC) mechanism to provide location information, and applications can use it to become geo-aware

• Can geocode (getting a Position(longitude/latitude coordinate) from an Address) and reverse-geocode (getting an Address from a Position)

• Licensed under the GNU LGPL– WiFi-based geolocation (accuracy: in meters)– GPS(A) receivers (accuracy: in centimeters)– 3G modems (accuracy: in kilometers, unless modem has

GPS)– GeoIP (accuracy: city-level)

GeoClue

• Started during GNOME Summit 2006 in Boston• Provides a convenient way to find out where the

user is, from a number of sources such as GPS, GSM cell, WiFi network, internetwork

History & Goal

11Examples

GPS GSM IP address

User trackingWiFi

• Gobject• Glib• D-Bus• GPSD

– A GPS daemon on most Debian like system– http://gpsd.berlios.de

• Gypsy– Written by lain Holmes at o-hand– A GPS multiplexing daemon which allows multiple clients

to access GPS data from multiple GPS sources concurrently

– http://gypsy.freedesktop.org/wiki/

Dependencies (1/2)

• Wammu– A program to manage data in your cell phone such as

contacts, calendar or messages– http://wammu.eu/

• OpenCellID (basement station ID)– Aiming to create a complete database of CellID

worldwide, with their locations– http://opencellid.org/

Dependencies (2/2)

• A set of geoinformation interfaces– For querying “current situation”

• Position• Address• Velocity

– Use a method / signal architecture• Ex : To get current position,

Components (1/7)

geoclue_position_get_position() method or“position-changed” signal with a callback function

• Class of Interfaces– Position: GeocluePosition

• Via gpsd, gypsy, hostip, plazes, gsmloc– Address: GeoclueAddress

• Via hostip, plazes, manual, localnet– Velocity: Geocluevelocity

• Via gpsd, gypsy– Geocode: GeoclueGeocode

• Via nominatim (http://nominatim.openstreetmap.org/), geonames (http://www.geonames.org/), yahoo (http://developer.yahoo.com/maps/rest/V1/geocode.html)

– ReverseGeocode: GeoclueReverseGeocode• Via nominatim, geonames

– Accuracy: GeoclueAccuracy• Reports the horizontal and vertical accuracy levels

Components (2/7)

• Provider– Implement more than one Geoclue interface– All Geoclue providers are D-Bus services– Do not have to run as daemons, as D-Bus will start them

when needed (providers may also shut down when they’re no longer used)

Components (3/7)

• Type of Providers

Components (4/7)

Type Service Description

Hostip Position, Address A web service that guesses location based on the current IP address.

http://www.hostip.info

Plazes Position, Address A web service that gets location based on your current router mac address.

Interfaces with a user’s Plazes accounthttp://plazes.com

Manual Address A user-specified address

Localnet

Address User-specified address that maps to a routers mac address (home, office).

• Type of Providers

Components (5/7)

Type Service Description

Gsmloc Position Gets cell ID data, and estimates location from a web service based

upon that data

Gypsy Position, Velocity A GPS daemon that supports bluetooth and serial GPS devices

GPSD Position, Velocity A GPS daemon that uses TCP sockets

Yahoo Geocode A web service that converts an address to a position

Geonames

Geocode, ReverseGeocode

A web service that can convert an address to a position. Conversely, it

can also find the nearest address to a given position.

• Problem on using Providers– A single provider cannot be the best solution to all problems– The “best” providers will be different depending on the user

• Master Provider– Single window for user to use providers

• It is an attempt to take away all of the complications of choosing the right provider

– Choose the best provider to provide what you are looking for based on client requirements and provider availability, accuracy and resource requirements

– The provider that is actually used may change over time as conditions change, but the client can just ignore this

Components (6/7)

• Usage of Master Provider– A typical Master provider use :

• Getting a client-specific GeoclueMasterClient from GeoclueMaster

• Setting GeoclueMasterClient requirements (such as accuracy)

• Starting the wanted interfaces (such as Position)• Using the client just like a regular provider

– Master provider is fairly new and may not be as stable as the rest of Geoclue

Components (7/7)

21Example : Master Provider

22Example : Master Provider

• http://www.slideshare.net/wiliwe/geoclue-the-geolocation-service

• http://www.freedesktop.org/wiki/Software/GeoClue/

• https://download.tizen.org/misc/media/conference2012/wednesday/ballroom-b/%202012-05-09_1145-1225-overview_of_tizen_location.pdf

• Isaac K Adusei, K. Kyamakya, Klaus Jobmann, “Mobile Positioning Technologies in Cellular Networks: An Evaluation of their Performance Metrics”

References

SKKU Embedded Software Lab. 23 1 Tizen Location Framework.

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