2. SEMINAR ON
Atmospheric Pressure-Aware
Seamless 3-D Localization and
Navigation for Mobile Internet
Devices
PRASHOB N PAVANAN
ROLL NO : 09
S7 ECE
17-10-2013
Dept. of ECE
SEMINAR GUIDE
Ms NIMITHA
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Navigation for Mobile Internet Devices
CONTENTS
•
INTRODUCTION
•
TECHNIQUES USED FOR LOCALIZATION AND NAVIGATION
•
CURRENTLY USED METHODS
•
ADVANTAGE OVER OTHERS
•
BLOCK DIAGRAM
•
ALTITUDE DETERMINATION
•
ADDITIONAL HARDWARE
•
IMPROVED ACCURACY OF 2D LOCALIZATION
•
2D LOCALIZATION ERRORS
•
ERROR REDUCTION USING 3D AUGMENTED MODEL
•
HOW THE SEAMLESS 3D LOCALIZATION WORKS
•
APPLICATIONS
•
CONCLUSION
•
REFERENCE
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for Mobile Internet Devices
INTRODUCTION
• Advances in Wireless cellular networks
• Provide bandwidth for mobile to access the internet
• In addition
– More powerful processor
– Sensors
• Enables Smartphone for several services like
– User current location
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Continues…..
-LBS (Location Based Service)
-Both indoor and outdoor navigation,
Utilizing GPS(Global Positioning System)
o Outdoor-strong GPS signals
o Indoor –weak GPS signals
-RSS (Received Signal Strength) based
Fig 1(a) : Satellite used for
GPS
localization
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TECHNIQUES USED FOR LOCALIZATION AND
NAVIGATION
• Traditional triangulation localization
• Using RADAR (Radio Detection And Ranging)
• GPS
• WIFI Localization
Figure 1.1 showing GPS navigation
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CURRENTLY USED LOCALIZATION
METHODS
• Designed for two-dimensional (2-D) conditions
• No altitude information
• Less accuracy
• Not possible for localization and navigation in multi-storied
buildings and navigation around the mountain
• 3D localization based on RFID ( requires more computing
capability)
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ADVANTAGES OVER OTHERS
• Provides accurate altitude information
• Improves the accuracy of indoor RSS based localization using
the altitude information
• Provides seamless 3-D localization and navigation Service
across indoor and outdoor environments
• Uses atmospheric pressure for the altitude determination
• Possible with all android smart phones which uses an
application software for downloading the maps
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BLOCK DIAGRAM
Fig. 1 : Seamless 3-D localization and
navigation system framework
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• IN OUTDOOR ENVIRONMENTS
• Such as mountains
Fig 1.2 : Mountains
• IN INDOOR ENVIRONMENTS
Figure 1.3 : showing indoor and
outdoor navigation
• Buildings have different layouts on different floors
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p2
p1
Fig. 2 :Navigation in a multi-story building
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ALTITUDE DETERMINATION
H
T0 /( dT / dH ).[1 ( P / P0 ) (
dT / dH ).R / g
]
where,
H – Altitude
P - Measured atmospheric pressure
To - Temperature.
dT /dH - Temperature gradient with the altitude
Po - Standard atmospheric pressure
g – Acceleration of gravity
R - Gas constant.
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By substituting values
Equation changes to
i e; dT /dH =−6.5 K/km
Po =101325 Pa
g = 9.82 m/s2
R=287.052 m2 /(s2∙K)
H
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T0 /(6.5 K / km).[1 ( P / 101325 Pa ) 0.19 ]
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Continues…..
• Measured pressure -used to calculate the altitude
• Pressure is measured using pressure sensor
• Height error much less than 0.5 m which is
enough to specify the floor
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ADDITIONAL HARDWARE
Fig. 3 : Atmospheric pressure sensor and
communication module
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• Some smart phones have an integrated atmospheric
pressure sensor
Or
• Attached through a blue tooth transceiver
• It also uses
• Microcontroller
• Battery
• Power management unit
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IMPROVED ACCURACY OF INDOOR 2-D
LOCALIZATION METHOD
• Calculation of distance between sender and receiver is
based on RSS (received signal strength)
• Attenuation Happens during transmission
• RSS is related to distance
• As the distance between the anchor nodes increases the
signal strength decreases
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• Distance can be calculated as
q Q 10r lg d
E
where ,
q - Measured RSS
d - Distance
Q -RSS at a distance of one meter (remains constant)
r - Path loss exponent
E - Random variable
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• E has little effect and can be omitted
Thus,
d 10
( Q q / 10 r )
• It can be used to calculate d from q and r
• d is used in 2-D localization to calculate the location
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2-D LOCATION SYSTEM ERRORS
• A multi-story building may have many Wi Fi-APs
• It is deployed on different floors
• The AP’s on the different floors are described in a 3D
coordinate system
• It convert the 3-D coordinates to 2-D coordinates by
ignoring the Altitudes
• 2-D localization - cause a localization error
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Attenuation by the floor
The L is larger than the true distance
Device receives the
attenuated signal
Fig. 4 : Position relationships between the user and the APs
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Continues….
• RSS will not be accurate
• Received wireless signal is attenuated by the floor slab
• It is mainly concrete and thicker than the walls
• L is larger than the true distance between the user and AP3
FIG:WAP54G
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Fig 4.3 : Indoor navigation using software
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Fig 4.3(a) : Indoor navigation
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Navigation for Mobile Internet Devices
REDUCING ERRORS USING AUGMENTED 3D MODEL
• A better approach - Real 3-D Coordinate System
– It is used to describe the locations of the APs and the user
– Complex
• An alternative approach
– Augmented 3-D model
• Movement on the stairs is neglected
– Floor number is enough to describe the user altitude
• L′ is the true distance value ( Fig 4)
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• C is added to account for the signal attenuation by the floor
slab and for the AP on the 2nd floor and user on the 1st;
d
( Q ( q c ) / 10 r )
10
• Compensation C depends on
– Floor thickness
– Material
• Approximate d to L
• If AP is on the floor 3 and the user on the floor 1 then the C
doubles
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• After considering the Signal Strength Attenuation
• L can be calculated
• L′ can be calculated using the Pythagorean theorem
L'
L2
H2
where
H - Distance between neighbouring floors
L′ - Projection value
L - Distance
•
Improves the localization method accuracy
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STEPS OF LOCALIZATION METHOD
• Step 1: check the APs that can be identified to find which APs
are on the same floor as the user and which APs are on the
different floors
• Step2:calculate the distance from each AP to the user.
The distances between the AP s on the different floor and
user are found
• Utilize the traditional triangulation localization method to
calculate the location
le Map APIs
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BRIEF IDEA OF TRIANGULATION
USER OR OBJECT
AP 1
AP 2
;
Outdoor navigation software based on the Google Map APIs
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HOW SEAMLESS 3D NAVIGATION SYSTEM WORKS
Consider an office building with 4 floors:
1. In outdoor environments ,uses GPS transceiver and the
atmospheric pressure sensor to calculate 3D location
2. Indoor 3D localization uses 20 wi fi AP’ s to serve as anchor
nodes
3. The smart phone automatically calculates the indoor
location based on RSS from Wi fi AP’ s
4. The Application Programming Interfaces of Google updates
the map of the current location
5. When user enters the building , the software downloads the
location information for each WiFi AP in the building
,including the horizontal location and floor number ,map of
Outdoor navigation software based on the floors and
each floor , altitude, the distance betweenGoogle Map APIs
compensation C for each floor
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Atmospheric Pressure-Aware Seamless 3-D Localization and
Navigation for Mobile Internet Devices
Outdoor navigation software based on the Google Map APIs
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Navigation for Mobile Internet Devices
PRESSURE DETERMINATION
• In certain smart phones have the integrated pressure sensor ,
temperature sensor and also humidity sensor
• The software running in the smart phone uses the pressure
value to get the altitude information in real time
• The atmospheric pressure decreases as the altitude increases
and vice versa
• The altitude or atmospheric pressure can be used to
determine the floor number
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Navigation for Mobile Internet Devices
Fig: 7 Altitude determined by the pressure sensor
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Fig 7.1: Altitude vs Pressure
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Fig 7.2: Atmospheric Pressure
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Navigation for Mobile Internet Devices
APPLICATIONS
•Used for navigation inside a large shopping mall
•Helps in easy navigation in hilly areas
•Can keep the track of the user
•Helps for the real time measurement and monitoring of
pressure
•Helps to identify easily the location based services
Figure
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CONCLUSIONS
• Seamless 3-D localization and Navigation System uses
Atmospheric Pressure Sensor
• Provide better guidance indoors or outdoors
– Including multi-story buildings or high mountains(on a map
on the user’s device)
• Accuracy
– more accurate than the traditional 2-D localization
method
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Navigation for Mobile Internet Devices
REFERENCES
• Bahl P, Padmanabhan : An in-building RF-based user location
and tracking system
• Chintalapudi K, Padmanabha I A, Padmanabhan V N. Indoor
localization without the plain
• Youssef M, Agrawala A, The Horus WLAN location
determination system
• www.wikipedia.com
• ieeexplore.ieee.org
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