eth zurich engineering geodesy - prof. dr. h. ingensand the challenges of indoor environments and...

ETH ZurichEngineering Geodesy - Prof. Dr. H. Ingensand

The Challenges of Indoor Environments and The Challenges of Indoor Environments and Specification on some Alternative Specification on some Alternative

Positioning SystemsPositioning Systems

Rainer Mautz

ETH ZürichInstitute of Geodesy and Photogrammetry

6th Workshop on Positioning, Navigation and Communication (WPNC'09), 19.3.2009


Overview of Positioning Systems GNSS Alternative Positioning Systems Conclusions & OutlookOverview of Positioning Systems GNSS Alternative Positioning Systems Conclusions & Outlook

ContentsContents

1. Overview of Systems1. Overview of Systems

2. GNSS2. GNSS

3. Alternative Positioning Systems3. Alternative Positioning Systems- Locata- Locata- iGPS- iGPS- Ultrasound- Ultrasound- CLIPS- CLIPS

4. Conclusions & Outlook4. Conclusions & Outlook


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10 μm 100 μm 1 mm 1 cm 1 dm 1 m 10 m 100 m Accuracygraphic: Rainer Mautz

Classification of Positioning Systems

Further classification by:

Signal wavelength (Radio Frequencies, Light Waves, Ultrasound, RFID, Terahertz)

Principle (trilateration, triangulation, signal strength)

Active / passive sensors

Application (industry, surveying, navigation)



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CLI

PS

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graphic: Rainer Mautz

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graphic: Rainer Mautz

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CLI

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GNSS – Performance:

System Principle

CoverageReal-time

Accuracy RangeData Rate

Market CostOutdoor Indoor

Geodetic GNSS

TOA, lateration, differential technique

() mm global 20 Hz yesmoderate

to high

in addition:

strong attenuation fading: reflections, diffraction, scattering no general model

no direct line-of-sight:

obstacles

multipath

limitations:



Material [dB] Factor [-]

Glass 1 - 4 0.8 – 0.4

Wood 2 - 9 0.6 – 0.1

Roofing Tiles / Bricks 5 - 31 0.3 – 0.001

Concrete 12 - 43 0.06 – 0.00005

Ferro-Concrete 29 - 43 0.001 – 0.00005

Attenuation of various building materials (L1 = 1500 MHz)

Stone (1997)

Signal Strength in Decibel Watt of GNSS Satellites

Environment [dBW]

Satellite +14 signal strength delivered from satellite

Outdoors -155 unaided fixes OK for standard receivers

Indoors -176 decode limit for high sensitive receivers

Underground -191 decode limit for aided, ultra-high sensitive receivers

Indoors:

100 times weakerunderground:

10000 times weaker

How to overcome attenuation? Increase receiver sensibility Increase satellite signal power Ultra wideband GNSS signals Assisted GNSS



Terrestrial pseudolite transceivers, Locata Corporation in CanberraAugmentation for GNSS in urban canyons, pit mines, buildings

Alternative Positioning Systems - Locata

Picture from Jonas BERTSCH: On-the-fly Ambiguity Resolution for the Locata Positioning System, Master Thesis, ETH Zurich, February 2009.



System Principle Outdoor IndoorReal-time

Accuracy RangeSignal

FrequencyData Rate

Market Cost

LocataTOA,

lateration

2 mm static 1 cm

RTK,2 - 3 km RF 1 Hz

in progress

high

Locata – Key Parameters:

(+) RTK: 1 – 2 cm deviations at 2.4 m/s(+) signal magnitude stronger than GNSS(+) indoors dm Challanges:

multipath (low elevation)

Synchronisation < 30 pico-seconds Picture from J. Barnes, C. Rizos, M. Kanli, A. Pahwa „A Positioning Technology for Classically

Difficult GNSS Environments from Locata“, IEEE Conference, San Diego California, 26 April 2006



iGPS – “laser resection”

PrincipleOutdoo

r Indoo

rReal-time


FrequencyData Rate

Market Cost

TOA angular measurements

0.1 – 0.2 mm

2 - 50 m RF 40 Hz in progress high

Key design:

two or more fixed transmitters rotating fan-shaped laser beams infrared signal various sensors detect arrival times position determination with spatial forward intersection

graphic from Metris



iGPS

iGPS transmitter and sensor during a test in a tunnel



iGPS

Application of iGPS in a tunnel.

Master Thesis, ETH Zurich by DAVID ULRICH: Innovative Positionierungs-systeme im Untertagebau, July 2008

Results

Strengths:- High accuracy (0.1 mm) confirmed- Real-time, 40 Hz confirmed

Problems:- Multipath- Influence of light sources



Ultrasound Systems – Crickets, Active Bat, Dolphin



FrequencyData Rate

Market Cost

CricketTOA,

lateration 1 – 2 cm 10 m ultrasound 1 Hz

development

low

Active BatTOA,

lateration 1 – 5 cm 1000 m2 ultrasound 75 Hz no moderate

DOLPHINTOA,

lateration 2 cm

room scale

ultrasound 20 Hz no moderate

Method:

TOA, TDOA (ultrasound & RF) Multilateration



Problems:

dependency on temperature maximal range deployment of reference beacons multipath reliability interference with other sound sources

Ultrasound Systems – Crickets

Ceiling

Floor

Beacon Listener

Student Project: Robot Positioning



Optical Positioning Systems: ProCam System (AICON)

Mobile probe with CCD camera. Spatial resection of measuring head.

relies on coded reference targets. (illuminated by an infrared flash)



FrequencyData Rate Market Cost

ProCam optical 0.1 mm any room infrared 90 points / h yes high

Pictures from: http://www.aicon.de



Optical Positioning Systems: CLIPS (Camera and Laser Indoor Positioning System)

Production of laser “hedgehog”

Principle Outdoor IndoorReal-time


FrequencyData Rate

Market Cost

Image Based mm-level 15 m visible light 30 Hz no low



CLIPS

Principle:

P5

P4

P1

P2

Laser Pointer Hedgehog

(fixed)

basevector

P3

Camera(mobile)

Object

Probe(optional)



CLIPS

Difficulties in detection of laser spots



Conclusions Outdoors: GNSS dominating system for open-skyOutdoors: GNSS dominating system for open-skyIndoors: Indoors: No overall solution yet No overall solution yet

Several indoor systems on the marketSeveral indoor systems on the market low accuracy low accuracy sophisticated setups sophisticated setups limited coverage area limited coverage area inadequate costs inadequate costs

Outlook signals will penetrate buildings signals will penetrate buildings use existing infrastructure use existing infrastructure for higher accuracy are local installations unavoidable for higher accuracy are local installations unavoidable

Project CLIPS: Building own indoor positioning system!Project CLIPS: Building own indoor positioning system!



End

eth zurich engineering geodesy - prof. dr. h. ingensand the challenges of indoor environments and...

Documents

overview of systems

ingensand gnss performance

ingensand range graphic

ingensand range clips

indoor outdoor range

rainer mautz range clips

igps ultrasound

strong attenuation