Positioning technologies Anto Aasa Augsburg 2019 - - PowerPoint PPT Presentation

Positioning technologies

Anto Aasa Augsburg 2019

http://aasa.ut.ee/augsburg

Location aware search

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http://aasa.ut.ee/augsburg

• How to determine a location?

– „Where are you?“ – GPS (Global Positioning System)

• Galileo, GLONASS

– Mobile positioning – WiFi, Bluetooth – RFID (Radio-frequency identification) – NFC (Near Field Communication)

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GNSS

• (Global Navigation Satellite System) is a

satellite system that is used to pinpoint the geographic location of a user's receiver anywhere in the world.

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Systems:

• GPS (global positioning system): USA
• GLONASS (Глобальная навигационная

спутниковая система): Russia

• BeiDou: China
• Galileo: EU
• IRNSS (Indian Regional Navigation

Satellite System). India

• QZSS (Quasi-Zenith Satellite System):

Japan

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Global

• GPS
• GLONASS
• Galileo
• Compass (BeiDou 2)

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Galileo satelliite constellation

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GLONASS vs GPS

GLONASS GPS

http://science.nasa.gov/realtime/jtrack/3d/JTrack3D.html/

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BeiDou, China

http://www.nature.com/articles/srep04692/figures/1

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2012 – regional 2020 – global

Indian Regional Navigation Satellite System NAVIC

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QZSS, Japan

3 + 1 satellites Quasi-Zenith Satellite System

GPS

• Global Positioning System

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• GPS:

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Dilution of precision (DoP)

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• GPS-chip:

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Wireless communication

• Signals

– Radio – Light

• Communication between fixed and mobile

terminals

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Different „things“ in different frequencies

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• Antennas
• Speed of electomagnetic waves
• Refraction of electromagnetic waves

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Multipath propagation

• Signal reaches the receiving antenna on

various paths

– reflection – shadowing – diffraction – scattering

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Architecture and operation of mobile network is very complex

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Principles of positioning

• Selection of positioning method
• Selection of essential measuring parameters

(angle, distance, range, speed) – usually relationships between two objects one of which is fixed in space

• Reference system (descriptive vs spatial)
• Infrastructure
• Protocol & script – management of positioning

process

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Quality of positioning

• Accuracy and precision
• Yield and consistency
• Overhead
• Power consumption
• Latency
• Roll-out and operating costs

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Accuracy and precision

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Positioning infrastructures

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• Dead reckogning

– (Ariadne’ thread) – Position and direction of motion and velocity and distance – Tunnels?

Gyroscope Accelerometer Odometer

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Satellite navigation

• First satellite (sputnik): 1957. Soviet Union
• USA Explorer I 1958.
• First satellite navigation system Transit

– 7 satellites; 1964; US Navy – 1 position fix = 15 minutes

• GPS started 1978.

– 24 satellites – GPS III generation

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Satellite navigation

• Advantages:

– accuracy – global availability;

• Disadvantages:

– energy consumption, – slow start, – not for indoor use, – need for open sky – enourmous capital invstements.

Integration with mobile phone A-GPS

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A-GPS

• Assisted GPS
• Advantages:

– higher accuracy, – faster position fix, – lower energy consumption,

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A-GPS

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A-GPS in mobile phone

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Mobile positioning

Operator based Terminal based

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Mobile positioning methods

• CGI – cell identification
• 3G SAI - Service Area Identity
• E-CGI – enhanced cell identification
• TOA – time of arrival
• E-OTD - enhanced observed time deifference
• TDOA - time difference of arrival
• AOA – angle of arrival
• A-GPS – assisted GPS
• Hybrid

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GSM positioning

• CGI (Cell Global Identity)
• CGI+TA (Cell Global Identity + Timing

Advance)

• ...
• ...

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CGI

Cell Global Identity

• Accuracy ranges from

below 100 m up to 35 km

• Fast

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CGI-TA

Omni Sector

26.02.2019

Cell Global Identity + Timing Advance

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3G SAI

• Predefined areas
• Fast
• Accuracy

– 150...500m urban – 1000...5000m rural

26.02.2019

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A-GPS

• Assisted-GPS
• Ellipse/ring
• accuracy 5...150m
• Works in „hard“

conditions

• Position fix 15...25 sec

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Hübriid

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E-OTD

26.02.2019

Enhanced Observed Time Difference.

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AOA Angle of Arrival TDOA Time Difference of Arrival

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Antenna sector + distance CGI-TA

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3G A-GPS

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GSM cell-plan for Tartu

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3G

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Theoretical antenna coverage

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Accuracy for different methods

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Spatial Triggering

Function which automatically notifies client after the criteria is fullfilled Criteria:

• phone enters in the area;
• phone leaves the area;
• 2 phones are closer than

defined.

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Terminal based positioning

• GPS
• CGI
• WiFi
• Bluetooth
• hybrid

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Passive mobile positioning

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GPS: YouSense / Mobility Log A-GPS WiFi Gyroscope Acceleromater ,,,

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Accuracy vs battery

Energy consumption Accuracy

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