Location Based Services CE51600-1 Software Development 13/04/2017 Location Based Services What is a Location Based Service? How is a LBS useful? Components What’s special about it? Context Adoption Privacy How does it work? Services request processing Mobile positioning Architectural requirements Lot to get through Lecture 1 - Introduction

Introduction to LBS A certain service that is offered to the users based on their location An information service provided by a device that knows where it is and modifies the information it provides accordingly Mobile services that utilise user location information to add value to the service Usually require modifications in either the networks or the mobile device or both It was first developed for the military and emergency services

LBS: Then For how many years have we used these signs as the ONLY source for LBS? Version 1.2 Feb 2009

LBS: Now Location-based traffic reports: Range query: How many cars on the motorway? Shortest path query: What is the estimated time travel to reach my destination? Location-based store finder: Range query: What are the restaurants within five miles of my location? Nearest-neighbor query: Where is my nearest fast food restaurant? Location-based advertisement: Range query: Send E-coupons to all customers within five miles of my store

It’s 4:30pm and Mum is stuck in traffic inTouch checks her calendar and sees she’s supposed to pick up Cindy from ballet Version 1.2 Feb 2009

Mum’s phone senses that she is in a traffic jam, and automatically prepares a status message Mum hits “send”, and Cindy sees that Mum is running late. Cindy decides to wait inside.

LBS: Why Now ? GIS/ Spatial Database Mobile GIS Web GIS LBS Internet Mobile Devices GIS/ Spatial Database Web GIS LBS Mobile Internet Mobile GIS LBS is a Convergence of Technologies Version 1.2 Feb 2009

LBS Applications Version 1.2 Feb 2009

LBS Components (1) Mobile Devices Communication Network A tool for the user to request the needed information The results can be given by speech, using pictures, text... PDAs, Mobile Phones, Laptops, a car navigation unit, a toll box for road pricing in a truck Communication Network The mobile network Transfers the user data and service request from the mobile terminal to the service provider Transfers the requested information back to the user Version 1.2 Feb 2009

LBS Components (2) Positioning Component For the processing of a service usually the user position has to be determined The user position can be obtained either by using the mobile communication network or by using the Global Positioning System (GPS) Further possibilities to determine the position are WLAN stations, active badges or radio beacons (indoor navigation) If the position is not determined automatically it can be also specified manually by the user Service and Application Provider Responsible for the service request processing Calculation of the position, finding a route, searching yellow pages with respect to position or searching specific information on objects of user interest Version 1.2 Feb 2009

LBS Components (3) Data and Content Provider Service providers will usually not store and maintain all the information which can be requested by users Geographic base data and location information is requested from the maintaining authority (e.g. mapping agencies) or business and industry partners (e.g. yellow pages, traffic companies) Version 1.2 Feb 2009

LBS- Context (1) Mobile user identity Age and gender - children are unlikely to be interested in knowing about bars and pubs Personal preferences – Language, style, imagery, colours Location - the most commonly considered element of context It allows information and services to be localized Time - An entertainment’s active time might be used to determine if an event was still valid, for example a concert or a venue is open Orientation - the direction a user is heading in and thus what is in front, behind and to either side of them In a tourist guide this might be used to determine what historical building the user is facing In a navigation service it is important to check the user is heading in the right direction Version 1.2 Feb 2009

LBS- Context (2) Navigation history Purpose of use allows the users to see where they have been and what they have seen and done orientate a user while they're are moving and allow them to backtrack if they get lost help to build up a profile of the what the user is interested in, enhancing the provision of relevant information Purpose of use Defined by the activities, goals, tasks and roles of users. Different types of usage require different Types of information Types of presentation, for example maps, text or speech, and Modes of interaction Version 1.2 Feb 2009

LBS- Context (3) Social and cultural situation Physical Surroundings proximity to others social relationships collaborative tasks Physical Surroundings lighting level or how much ambient noise there For example direct sunlight will make screens more difficult to read requiring the contrast to be adjusted System Properties to the computer infrastructure the user is employing What type of device they are using and what are its capabilities a continuous internet connection or it is only intermittent, bandwidth, the quality of the positioning information, e.g. the GPS coverage. Version 1.2 Feb 2009

LBS- Context How do services respond to context? Information level Technology level User interface level Presentation level Version 1.2 Feb 2009

LBS- Privacy Like many technologies, LBS have an enormous potential for good but they can also be misused. The potential for misuse doesn’t invalidate the technology, but it does mean that we must be thoughtful about how we apply it, especially during its developmental stages. Version 1.2 Feb 2009

Major Privacy Threats YOU ARE TRACKED…!!!! “New technologies can pinpoint your location at any time and place. They promise safety and convenience but threaten privacy and security” Cover story, IEEE Spectrum, July 2003 Version 1.2 Feb 2009

Major Privacy Threats http://technology.guardian.co.uk/news/story/0,,1699156,00.html http://wifi.weblogsinc.com/2004/09/24/companies-increasingly-use-gps-enabled-cell-phones-to-track/

How does it Work? Version 1.2 Feb 2009

Positioning Methods Version 1.2 Feb 2009

Location Technologies GPS - Global Positioning System AGPS - Assisted GPS Cell ID Cell ID + Timing Advance Signal Strength Based AOA - Angle Of Arrival TOA - Time Of Arrival TDOA - Time Difference of Arrival EOTD - Enhanced Observed Time Difference Keypad based (click the address yourself) Hybrid solutions RF Fingerprinting (on phones that will support WLAN) Version 1.2 Feb 2009

GPS With the launch of Sputnik in 1957, radio-based global positioning became a (theoretical) possibility TRANSIT This was a very crude form of GPS using only one satellite (1960s) Submarines used it Could only be used every 35-45 minutes Submarine had to be still Version 1.2 Feb 2009

Components of GPS and how it works Space (e.g. satellites) Control (i.e. a ground station at a known geographic location) User The GPS receiver precisely measures the time it takes a signal to travel from a satellite to the receiver There are lots of satellites Version 1.2 Feb 2009

CE51600-1 Software Development 13/04/2017 Details 6 orbital planes, included at 55 degrees to the equator, each with 4 satellites 21 active satellites, 3 backups Orbit the earth at 12,541 miles and have an orbital period of 11 hrs. 56 min. Lecture 1 - Introduction

Satellite Triangulation GPS receiver links to the handset As reference to the nearest 3 satellites the receiver calculates the exact position

Selective Acquisition The US military was concerned about the possibility of terrorists or other unfriendly people using GPS to precisely guide a missile (or other unfriendly device) The deliberately introduced errors in the time embedded in the signal This caused locations to be up to 100m off Turned off on 2 May 2000 GPS III system will launch in 2014 http://scpnt.stanford.edu/pnt/PNT09/presentation_slides/2_Podlesney_ GPSIII.pdf Should be even more accurate than the 8m accuracy limit currently in place Galileo is a European Union Equivalent http://ec.europa.eu/transport/galileo/index_en.htm Version 1.2 Feb 2009

Assisted GPS Conventional GPS has difficulty providing reliable positions in poor signal conditions When first turned on in these conditions, some non- assisted GPS units may not be able to download the information from the GPS satellites GPS has a slow time to fix unless it is permanently tracking satellites To solve the inherent restrictions with GPS, Assisted GPS was proposed Assisted GPS is based upon providing GPS satellite information to the handset, via the cellular network Version 1.2 Feb 2009

A-GPS Assisted GPS gives improvements in Assistance Data Time to First Fix Battery Life Sensitivity Cost Assistance Data Satellite Position Time information Visible GPS List Version 1.2 Feb 2009

Cell ID (Cell of Origin) Cell based positioning No calculation Least accurate than others Accuracy is dependent on cell density Compatible with all handset and GSM network Version 1.2 Feb 2009

Timing Advance (TA) Power level or time taken at phone logged at Base Station Calculation based on signal loss or time taken for signal travel Compatible with all handset and GSM network Resolution is 500 meters Version 1.2 Feb 2009

Signal Strength Based Measure signal strength from the control channels of several Base Stations If signal levels from 3 different BSs are known, it’s possible to calculate the location Version 1.2 Feb 2009

Time of Arrival (TOA) Location Measurement Units (LMU) at Base Station Measure access requests from handset Triangulation calculated from combined information Compatible with all handset and GSM network Version 1.2 Feb 2009

AOA - Angle Of Arrival Measure the angle of arrived signal between base station and mobile station Location error increases as mobile is far from BSs Version 1.2 Feb 2009

Time Difference Of Arrival Measure the time difference of arrived signal between base station and mobile station : Minimum three base stations Mobile station locates at the intersection point which will be made by more than 3 hyperbolas Version 1.2 Feb 2009

Enhanced Observed Time Difference Added device, LMU (Location Measurement Unit), whose location is known LMU and mobile station measure the time difference of arrived signal from base station at the same time Mobile station locates at the intersection point which will be made by more than 3 hyperbolas Version 1.2 Feb 2009

EOTD – Enhanced Observed Time Difference Version 1.2 Feb 2009

Keyboard Based You set your location! Example: Navigation Software: Manually set origin Manually set destination Approve when each step is completed to get the next step instructions Version 1.2 Feb 2009

Lampposts Based Last Mile company plans to offer Internet & LBS using street lampposts A flash memory will be installed inside the lampposts and store info about local pubs, shops. Cost: about £500 per lamppost Version 1.2 Feb 2009

Hybrid Solutions Based Improve effectiveness Extends the coverage of a solution e.g. AGPS Common Hybrids EOTD / AGPS Cell ID / AGPS Benefits of both systems realized increasing the accuracy and availability of any single method Version 1.2 Feb 2009

RF Fingerprint Based Pinpointing wireless clients makes it easier to secure and manage wireless LANs WLANs typically have used closest access point (closest AP) or triangulation technologies to track location RF fingerprinting improves by taking into account the effects that a building or people will have on an RF signal - characteristics such as reflection, attenuation and multi-path Version 1.2 Feb 2009

RF Fingerprint Based Version 1.2 Feb 2009

Range Of Coverage AGPS,GPS, GPS Hybrids 5 m 100 m EOTD 300 m TDOA, AOA Cell ID + TA 500 m Cell ID 1000+m Version 1.2 Feb 2009

Major Technologies Table Technology Handset impact Accuracy Cell ID none Depends on the size of the cell 100m-3km Cell ID + TA 500m TDOA 100-200m AOA EOTD yes 20-200m GPS/AGPS 5-30m

Code of practice Regulation play a major role in the shape and success LBS. Regulation is likely to have an impact on the accuracy operators will provide and the use of handling user information This will affect both technology choice and the availability and usability of user location information for different players Location based service providers that use location data as part of their services must comply with the Industry Code of Practice For the Use of Mobile Phone Technology to Provide Passive Services in the UK http://online.vodafone.co.uk/dispatch/Portal/appmanager/vodafone/wrp; wrpsessionid=FvsQQS4S5qMn4RJ02nwbkJLkwpxTbMt59HTgV57QJyt W2BygpZJ6!71690501?_nfpb=true&_pageLabel=template12&pageID= PRPP_0011 http://www.imcb.org.uk/assets/documents/SummaryofLBSCodeofPracti ce.pdf Version 1.2 Feb 2009