a distributed indoor navigation system leaving the trails thomas wießflecker terena networking...

A Distributed

Indoor Navigation SystemLeaving the Trails

Thomas Wießflecker

TerenaNetworking Conference 2009

Indoor Navigation Leaving the TrailsThomas Wießflecker June 11th, 2009

Everyday life in buildings Complex real estates Need for effective disaster management

Current situation in cities


Why do we need indoor positioning?

• Difficult overview and access

in case of hazard• Difficult to protect against terror• Favourite target

• Complicated navigation

in buildings

Increase building security

Save time and costs

Increase consumer satisfaction


Overview

• Introduction• Existing indoor positioning systems• A new approach:

Computer Aided Disaster Management System (CADMS)

• Building Information Model (BIM)• Indoor map matching• Evaluation• Conclusions


Why do we need to leave the trail?Existing positioning solutions

1. GPS cannot be deployed inside buildings

2. Systems based on RFID, WiFi, UWB depend on stationary infrastructure hardly adaptive, cost-intensive not suitable during an incident

3. Current map matching techniques cannot be deployed inside buildings

Development of a totally new approach at Graz, University of Technology

Main benefit of the CADMS: Autonomous indoor positioning


Approach to functioning indoor pos.

Development of a Computer Aided Disaster Management System (CADMS)

– Collecting acceleration data with Inertial Measurement Units– Sophisticated graphical user interface– Transmission of information to remote service customers

– Integration of imprecise sensor data and static data describing the real estate

• Development of a consistent Building Information Model (BIM)

• Embedding of dynamic sensor data into BIM data

Increase in positioning accuracy


Deployed hardware

Inertial Measurement Unit(IMU)

Head mounted display


System architecture

UpdateEngine data storing

local position data

remote position data

status information

network

floor plansdwg, dxf, atl

standardised XML format

signalling

status information

correctedposition data

additional building

information

CAFM

Real-time

verification andcorrection

communication

graphic displaywithin a lightweight application running in the control room

and on-site


The BIM’s requirements

• Represent up-to-date information about the real estate(digital floor plans, room information, room polygons, area information, doors, stairs, reference points, columns, shells, dangerous goods etc.)

• Allow for presenting this information in acontext-adaptive way include capabilities for indoor positioning

Context-adaptive BIM that also integrates sensor data and structural information, adaptable to events occurring during the deployment


BIM: Accessibility Model

real estate

building

floor

room

transition

area referencepoint

dangerousgoods

if located outsidethe building

area

transition

referencepoint

dangerousgoods

first floor

door

window

room 7

room 8

room 9

room 10

room 11

room 12

room 13

t5 t6

t7 t8


Map matching for road traffic

true position

corrected position

measured position Pt

Set of acutal streets

N

Set of estimatedarcs

N

tP

•Goals:

• Determine the arcPt should be associated with

• Determine the streetis currently on

• Determine the exact position on this street

N

tP


Again: Leaving the trailsDigital representations of buildings

Room

Door

?

Window

Vain attempts to model rooms and buildings by

using arcs

For the CADMS rooms are represented by polygons and doors by transition objects forming a 3D building model.

New indoor map matching strategies are desperately needed!

?

?


Indoor positioning

Improvement of plausibility and accuracy by integration of inertial measurement data and BIM data

• Automatic repositioning– Innovative map matching algorithms taking the geometry

of the building into account

• Manual repositioning– Correction of the displayed position by user interaction


Position determination

evaluation of physical correctness

plausibility checkand automaticrepositioning

manual repositioning

area determination

height calculation

plausibility level calculation

adjusted positionhistory

sensormeasurement data

user plausibility levelinformationstored in the

BIM

display

Decisions and subsystems

for automatic repositioning

Applied for each position measured by the IMU


Automatic repositioningin the domain of a door

• Only physically possible routes through the building are allowed to be covered.

• Drifting measurement results are adapted and corrected.


Door correction

current Room

next Room

1’

2’

intersection pointtrajectory - wall

door barycentre

t

t

21v

1. Determine the intersecting wall and the corresponding room polygon

2. Derive the intersection point of the polygon and

3. Move towards the door barycentre

4. Adapt the length of responding to the room’s geometry

5. Pass on point 2 up to the next layer of the CADMS

'2'1

t

t


Stair correction

height [m]

time [s]

012

-1-2

34 stair correction

performed

z-coordinate of the raw positions

z-coordinate derived by superimposing BIM data

23

45

1

7

89

6

)(..

'.212

211 SS

zSzS

zScP

covered route includes a stair

calculation of the corrected position


Stair correction – result


Manual repositioning

• Adaptation of measurement results by user interaction and short commands

• Repositioning (with reference points)

– Changing the room

– Changing the floor

– Entering/leaving the building

– Entering clearly identifiable areas: stairs, doors etc.

– Communicating the room number of the roomcurrently staying in

– …


Manual repositioning (examples)

Determine the absolute position with a reference point (door object)

“door on the left!”,“door on the right!”

Belated correction of entering the wrong room on the digital floor plan on the head mounted display

“other room!”


Qualitative evaluation (1)Uncorrected sensor data

Physical layer: IMU mounted on the pedestrian’s torso


Qualitative evaluation (2)Indoor map matching exploiting the BIM


2

3 4

5

11

12

1

first floor


Qualitative evaluation (3)Indoor map matching exploiting the BIM


second floor

6

7

8

910

7: manual correction


Qualitative evaluation (4)Physical layer: IMU mounted on the pedestrian’s foot

Uncorrected sensor data

Indoor map matching


Qualitative evaluation (5)Physical layer: IMU mounted on the pedestrian’s foot

Uncorrected sensor data Indoor map matching


Outcomes and conclusions (1)

• The measurement results reveal that the developed approach to providing seamless autonomous indoor positioning can function in practice.

• This is shown by using two different sensor subsystems and working with different building geometries.


Outcomes and conclusions (2)

• The combination of static BIM data and dynamically generated sensor data improves the accuracy of indoor positioning significantly.

• Providing more intelligent algorithms for the automatic repositioning helps avoiding time-consuming user interaction.

• A trade-off between intensive building modelling and greater positioning accuracy has to be made.


Future work

• Refinement of algorithms for the automatic repositioning techniques

• Standardisation of the BIM’s structure• Optimisation of the user interface• Tests during regular fire practices• Et cetera

Thank you for your attention!

a distributed indoor navigation system leaving the trails thomas wießflecker terena networking...

Documents

trails thomas wiefleckerjune

room information

area information

uptodate information

structural information

bim data increase

positioning accuracy

acceleration data