1. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)‏ Submission Title: Real Time Locating System based on IEEE 802.15.4a-CSS and ISO/IEC 24730-5 Date Submitted: 8 Nov, 2010 Company: Nanotron Technologies Address: Alt-Moabit 60, 10555 Berlin, Germany Voice: +49 30 399 954 103 E-Mail: r.hach@nanotron.com Re: Abstract: Purpose: Notice:This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release:The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 2 Real Time Locating System based on IEEE 802.15.4a-CSS and ISO/IEC 24730-5 Outline - General remarks on Real Time Locating Systems (RTLS) - Relationship between IEEE 15.4a-CSS and ISO/IEC 24730-5 - Overview over ISO/IEC 24730-5 - Architectures and applications - Summary © Nanotron Technologies GmbH 2 A. Rommel, R. Hach: “Real-Time Locating System based on ISO/IEC 24730-5”

3. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 3 General remarks on RTLS Typical applications are tracking (location and time) of goods, assets, persons,… All kind of media RF, inductive near field, ultra sound, (laser) optics, … and techniques Signal strength, Time of arrival (TOA), … are known

4. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 4 Focus of the presentation is TOA of RF signal The ability to the Time Of Arrival (TOA) of a signal enables you to use: -(Round Trip) Time Of Flight (TOF) -Time Difference of Arrival (TDOA)

5. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 5 RTLS is technically strongly related with RFID Standardization of RFID is done in institutions like ISO (International Standardization organization) There is an ISO committee* dedicated to RTLS *ISO/IEC JTC 1, Information technology,Subcommittee SC 31, Work Group 5

6. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 6 Difference between an IEEE 802 and ISO standard PHY MAC PHY MAC Tag Application layer IEEE 802 ISO: Air interface protocol which can be interpreted to consist of three layers

7. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 7 Relationship between IEEE 802.15.4a-CSS and ISO/IEC 24730-5 IEEE 802.15.4a added 2 PHYs to 15.4 UWB CSS (Chirp Spread Spectrum) finalized and published in 2007 ISO/IEC 24730-5 Air interface for RTLS based on CSS finalized and published in 2010

8. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 8 © Nanotron Technologies GmbH 8 Overview over ISO/IEC 24730-5 Wordwide applicable in ISM band at 2.4 GHz Based on CSS (Chirp Spread Spectrum ) 2-ary orthogonal (Up/Down Chirp) IEEE 802.15.4a-CSS 250kbit/s, 1Mbit/s Bandwidth: 80 MHz, 22 MHz Accurate location Reliable two way data communication Low power consumption

9. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 9 © Nanotron Technologies GmbH 9 4 types of packets:  Command packets are used by the infrastructure to transmit instructions to tags.  Report packets are used by tags to transmit any kind of information or notification to the infrastructure.  Ranging packets are used for ranging packet exchanges.  Blink packets are Broadcast packets transmitted by tags. Application packet types of ISO/IEC 24730-5

10. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 10 © Nanotron Technologies GmbH 10 R2R1 R4 T R3 Distance measurement between Readers and Tag Tag position calculated by trilateration PRO: no synchronization of infrastructure required CON: limited number of measurements per time interval due to high load of air interface. TOF with fixed infrastructure

11. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 11 © Nanotron Technologies GmbH 11 Measurement Results: TOF, Outdoor – Raw Data Area 20 x 20 m walking from anchor to anchor Multipath-free environment Accuracy better than 0.5m

12. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 12 © Nanotron Technologies GmbH 12 Moving Average #11 Accuracy in cm-range Measurement Results: TOF, Outdoor – Filtered Data

13. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 13 © Nanotron Technologies GmbH 13 Measurement Results, TOF, Indoor, Raw data

14. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 14 Applications specific for TOF No fixed location infrastructure Loss protection:monitor distance between parent unit and child unit Parent Unit Child Unit Cooperative RTLS: find locations relative to each other Unit A Unit B Unit C

15. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 15 © Nanotron Technologies GmbH 15 TDOA Architecture T RR RR RTLS Server R T Reader Tag Infrastructure (wired / wireless) T T T T T T  Tags send broadcast blinks  Readers measure TOA of tag blinks  RTLS server collects TOA measurements to calculate TDOA between reader pairs  PRO: Simultaneous reception of tag blinks by all anchors, high number of measurements per time interval  CON: Anchors require precise synchronization or very stable clocks

16. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 16 © Nanotron Technologies GmbH 16 R2 R1T TOA1TOA2 TDOA = 0 TDOA=0: Tag is on vertical line between R1 and R2 TDOA = D: Tag is on Hyperbola between R1 and R2 2D-Location requires 3 hyperbolas 3D-Location requires 4 hyperbolas R2R1 TOA1 TOA2 TDOA = D = TOA1-TOA2 T Location is calculated by finding intersections between hyperbolas

17. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 17 © Nanotron Technologies GmbH 17 TDOA Hyperbolas

18. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 18 © Nanotron Technologies GmbH 18 Applying TOF or TDOA Any blinking tags can be utilized for TDOA R Default State (Broadcasting) Ranging T T Tag enters area equipped with 24730-5 capable infrastructure R R R R R T Tag enters area equipped with TDOA capable infrastructure Blink State

19. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 19 © Nanotron Technologies GmbH 19 Applying TOF and TDOA T R R R R R T Blink State TOF for tags outside of area surrounded by readers TDOA for tags inside of area surrounded by readers

20. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 20 © Nanotron Technologies GmbH New Results Albrecht Rommel, Rainer Hach: Real-Time Locating System based on ISO/IEC 24730-5 Challenge for TDOA system: Precise synchronization of readers in multipath environment

21. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 21 © Nanotron Technologies GmbH 21 Synchronization of TDOA readers T T T T T T T T ref T R4/T ref1 T T T T T T R1/T ref2 R2/T ref3 R3/T ref4 Rx only readers Reference Tag at known location Rx/Tx readers (ISO/IEC 24730-5) Since readers are at known locations anyway they can serve as ‘reference tags’ R1 R2 R4 R3

22. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 22 System Architecture - Anchor Synchronization Tag Blinks Pacer Sync Blinks Tag RTC Synchronization (only for TDMA) © Nanotron Technologies GmbH 22 R2R1 P R3 Infrastructure (wired / wireless) Ethernet / UDP TOA2 TOA3 TOA1 TOA4 T T T T T T T R T Reader (known location) Pacer (known location) P Tags (up to 2400 @ 1Hz)  Pacer blink received by readers  TDOA with expected TDOA (geometry!)  Difference of measured vs. expected TDOA = Reader Phase Error  Low cost anchor synchronization Reader Synchronization Location Server RTLS Apps, GUI,... TCP Pro

23. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 23 System Architecture – Dynamic Pacer Dynamic Pacer: better reach of tags and readers © Nanotron Technologies GmbH 23 R2R1 PR3 T T T T T T T R2P R4R3 T T T T T T T R2R1 R4P T T T T T T T PR1 R4R3 T T T T T T T

24. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 24 Verification of time synchronization 1. Measure true timebase difference Common clock source Reader 1Reader 2 Tag 2. Estimate timebase difference from pacer blink Common clock source Reader 1Reader 2 Use cable of identical length Pacer blinks over air

25. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 25 © Nanotron Technologies GmbH 25 1. Measure true timebase difference, 2. Estimate timebase difference from pacer blinks

26. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 26 © Nanotron Technologies GmbH 26 TDOA Indoor – 80 MHz CSS © Nanotron Technologies GmbH 26 Setup  2.4 GHz ISM band  8 Dual-Channel Anchors, sync over air  one known fixed tag position  Ethernet connection to Location Server  All 16 sources used for location estimation  1000 blinks, 90% with less than 1m error

27. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 27 © Nanotron Technologies GmbH 27 TDOA Indoor – 22 MHz CSS © Nanotron Technologies GmbH 27 Setup  2.4 GHz ISM band  8 Dual-Channel Anchors, sync over air  one known fixed tag position  Ethernet connection to Location Server  All 16 sources used for location estimation  1000 blinks, 90% less than 1.7m error

28. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 28 © Nanotron Technologies GmbH 28 Tag

29. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 29 © Nanotron Technologies GmbH 29 Summary There is a significant difference between an ISO standard of an air interface protocol and an IEEE PHY/MAC standard ISO/IEC 24730-5 - contains the 802.15.4a Chirp Spread Spectrum PHY - defines two optional bandwidths values 22MHz and 80 MHz - defines a blink mode - defines message exchange protocols for ranging - allows precise time synchronization over the air (even in multipath environments) - can be used to realize applications like “loss protection” or “cooperative RTLS”

30. doc.: IEEE 15-10-0831-00-wng0 Submission Nov 2010 Rainer Hach (Nanotron Technologies) Slide 30 Thank you!