Combination of Indoor and Outdoor Positioning Dr Rainer

Combination of Indoor and Outdoor Positioning Dr. Rainer Mautz ETH Zürich Institute of Geodesy and Photogrammetry June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Contents Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook June 24 -26, 2008 ETH Zurich Conclusions & Outlook

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook User Requirements: availability: 100% of the timeliness: realtime reliability: no failures hybrid systems: to be avoided local installations: none accuracy: mm - cm coverage: global June 24 -26, 2008 ETH Zurich dynamic all environments: indoors: household, office & factory outdoors: urban & rural

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Classification of Positioning Systems: Ø Signal wavelength (Radio Frequencies, Light Waves, Ultrasound, RFID, Terahertz) Ø Principle (trilateration, triangulation, signal strength) Ø Environment (indoor, outdoor, urban, rural, remote) Ø Active / passive sensors Ø Accuracy (μm – km) Ø Application (industry, surveying, navigation) June 24 -26, 2008 ETH Zurich

GNSS Alternative Positioning Systems Conclusions & Outlook 100 m 1 km 10 km Overview of Systems 1 m Indoor 10 m Outdoor Range Positioning Requirements graphic: Rainer Mautz 10 μm 100 μm 1 mm June 24 -26, 2008 ETH Zurich 1 cm 1 dm 1 m 100 m Accuracy

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook GNSS – Performance: Coverage System Principle Geodetic GNSS TOA, lateration, differential technique Real. Accuracy time Outdoor Indoor ( ) mm Range Signal Frequency Data Rate Market Cost global RF 20 Hz yes moderate to high limitations: no direct line-ofsight: Ø obstacles Ø multipath June 24 -26, 2008 ETH Zurich in addition: Ø strong attenuation Ø fading: reflections, diffraction, scattering Ø no general model

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Number of satellites in space GPS GLONASS Galileo (United States) (Russia) (EU) Beidou, i. e. Compass (China) Current number 31 MEO 16 MEO 1 MEO, 4 GEO Future number 30 MEO 24 MEO 30 MEO 27 MEO, 5 GEO Full operational capability 1995 2011 2013 ca. 2010 Today: 10 satellites (open sky) 2013: 40 satellites (open sky) gain Implications on indoor environments ? marginal Other improvements: integrity, anti-jam power, security, clocks! June 24 -26, 2008 ETH Zurich number of satellites

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Attenuation of various building materials (L 1 = 1500 MHz) Material [d. B] Factor [-] Glass 1 -4 0. 8 – 0. 4 Wood 2 -9 0. 6 – 0. 1 Roofing Tiles / Bricks 100 times weaker 5 - 31 0. 3 – 0. 001 Concrete 12 - 43 underground: 0. 06 – 0. 00005 Ferro-Concrete 29 - 43 0. 001 – 0. 00005 Indoors: (1997) 10000 times Stone weaker Signal Strength in Decibel Watt of GNSS Satellites Environment [d. BW] 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 June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems How to overcome attenuation? GNSS Alternative Positioning Systems Conclusions & Outlook Ø Increase receiver sensibility Ø Increase satellite signal power Ø Use ultra wideband GNSS signals Assisted GNSS (AGNSS, AGPS) ephemeris, almanac via mobile phone (+) hot start, quicker position fix (-) long acquisition times indoors (-) high power needs for high sensitivity (-) accuracy degrades to m-level indoors graphic from: www. semsons. com June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Locata: Terrestrial pseudolite transceivers Picture from Barnes et al. (2003) 6 th. Iinternational Symposium on Satellite Navigation Technology , Melbourne, Australia June 24 -26, 2008 ETH Zurich Conclusions & Outlook

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Locata – Key Parameters: System Principle Locata TOA, lateration Outdoor Indoor Real. Accuracy time Range 2 mm static 1 cm RTK, 2 - 3 km Signal Frequency Data Rate Market Cost RF 1 Hz in progress high (+) RTK: 1 – 2 cm deviations at 2. 4 m/s (+) signal magnitude stronger than GNSS (+) indoors dm Problem: multipath (low elevation) 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 June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook i. GPS transmitter and sensor during a test in a tunnel June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook i. GPS – “laser resection” Principle TOA angular measurements Outdoor Indoor Real. Accuracy time 0. 1 – 0. 2 mm Range Signal Frequency 2 - 50 m RF Data Rate Market 40 Hz in progress Cost high Key design: Ø two or more fixed transmitters Ø rotating fan-shaped laser beams Ø infrared signal Ø various sensors detect arrival times Ø position determination with spatial forward intersection graphic from Metris June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Ultrasound Systems – Crickets, Active Bat, Dolphin Outdoor Indoor Real. Accuracy time System Principle Cricket TOA, lateration 1 – 2 cm Active Bat TOA, lateration 1 – 5 cm DOLPHIN TOA, lateration 2 cm Range Signal Frequency Data Rate Market Cost 10 m ultrasound 1 Hz develop ment low no moderate 1000 m 2 ultrasound 75 Hz room scale ultrasound 20 Hz Picture: Cambridge University June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Ultrasound Systems – Crickets, Active Bat, Dolphin Outdoor Indoor Real. Accuracy time System Principle Cricket TOA, lateration 1 – 2 cm Active Bat TOA, lateration 1 – 5 cm DOLPHIN TOA, lateration 2 cm Problems: Ø dependency on temperature Ø maximal range Ø deployment of reference beacons Ø multipath Ø reliability Ø interference with other sound sources June 24 -26, 2008 ETH Zurich Range Signal Frequency Data Rate Market Cost 10 m ultrasound 1 Hz develop ment low no moderate 1000 m 2 ultrasound 75 Hz room scale ultrasound 20 Hz

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions & Outlook Positioning based on Signal Strength Outdoor Indoor Real. Accuracy time System Principle Range Sonitor RSSI, Cell ID m-level 15 m RFID Signal Strength dm-m 20 m Signal Frequency Data Rate ultrasound 0. 3 Hz RF, 866 MHz Market Cost yes low no low All signals can be used: WLAN, Ultrasound, RF, GPRS, etc. Problems: Ø reliability Ø accuracy Picture from: USC Robotics Research Lab June 24 -26, 2008 ETH Zurich

Positioning Requirements Overview of Systems GNSS Alternative Positioning Systems Conclusions Outdoors: GNSS dominating system for open-sky Indoors: No overall solution yet Several indoor systems on the market - low accuracy - sophisticated set ups - limited coverage area - inadequate costs Outlook signals will penetrate buildings use existing infrastructure higher accuracy local installations unavoidable June 24 -26, 2008 ETH Zurich Conclusions & Outlook

End June 24 -26, 2008 ETH Zurich