Enabling Low-Cost Error-Free Wide-Area Passive RFID Real-Time Tracking

Enabling Low-Cost Error-Free Wide-Area Passive Real-Time Tracking Dr Sithamparanathan Sabesan, Dr Michael Crisp, Prof Richard Penty and Prof Ian White Department of Engineering University of Cambridge Email: ss740@cam.ac.uk

Commercial in Confidence Overview The Invention Introduction to Radio Frequency Identification () Motivation for Novel Long Range Adding RF Processing for Enhanced Tag Detection Solving the New Location Problem Developments Potential Applications Prototype Development Pilot Studies

Commercial in Confidence The Challenge Reduce lost luggage Could save airlines > 400M annually Monitor Passengers Late passengers contribute 10% of aircraft turn-around delays in the UK Costing airlines M annually Assist retailers and shoppers 40-50% of shoppers dissatisfied with time spent at checkouts 40% of fashion shoppers dissatisfied with stock availability.

Commercial in Confidence Identification Conventional approach - Barcodes Optical scanning required Questionable reliability? An advance - Conventional Proximity detection only

Commercial in Confidence Enables remote object detection and identification Advantages Passive Simple tag requires no local power source or maintenance Low cost Active Long range tag Good read reliability Disadvantages Short range in practice Reduced read reliability Difficult to determine location Battery powered High cost (200 times more cost than passive)

Commercial in Confidence Meeting the Passive Challenge Conventional Passive readers have a reliable read range much less than the maximum read range - due to points where the interrogating signals are cancelled due to reflections (nulls) Resulting in: a short practical range 1-2 m, often mis-reading tags and difficulty in determining tag location Many systems require: High tag reading reliability Longer range Precise location Robust installation The Cambridge approach meets these requirements

Commercial in Confidence Conventional System Small Area Portals Conventional systems give reasonable detection accuracy over short range (a few metres) Accuracy rapidly degrades over longer ranges (~10 m) even if individual tags support this distance

Wide-Area System Commercial in Confidence Cambridge System Area for coverage to be provided Out In In Out antenna transmission New system gives a 100% detection rate compared with <50% in a conventional system!

Commercial in Confidence Conventional Vs Cambridge Performance Conventional portal system Cambridge wide area system Detection/read accuracy Poor Excellent Reliability Low Very high Location accuracy Poor Precise Flexibility in installation s need to be at strategic, and potentially vulnerable, locations Relatively flexible location of antennas Misleading information Potential to confuse entering and exiting tags Confusion is avoided as system generates alert signal once tag is no longer detected/located

Commercial in Confidence Coverage Invention Conventional Passive readers have a reliable read range much less than the maximum read range due to nulls. Results in short reliable range ~2m, or potentially missed tags. Our Invention exploits RF techniques and multiple antennas to remove the problem of the nulls to facilitate a successful reading. Thus it is possible to achieve a near 100% read success rate (i.e. error free operation) of multiple tags over a large area. Reader Tag s Unit RF Processing

Y (m) Y (m) Commercial in Confidence Demonstration of Error Free Operation of New System over 2 x 19m Area! 20 20 15 10 Successfully read tag Null 15 10 5 5 0-1 -0.5 0 0.5 1 X (m) Conventional system with several read failures due to poor RF signal strength 0-1 -0.5 0 0.5 1 X (m) New system with error free performance due to advanced RF signal conditioning The number of read locations is increased from <80% to 100%, providing a >20% improvement in the current UHF system. Robust, low cost, large range tagging!

Developed a novel technique to allow tag location Commercial in Confidence Tag Location Invention Use RF Signal Conditioning to allow accurate triangulation Sub metre location accuracy is possible in passive, possibly even better with more signal processing Most recent results using off-line processing: range error = 0.5 m and std = 0.4 m location Tag location Late passenger alert

Commercial in Confidence Planed Application Demonstrations People Tracking Tracking passengers around terminal and reduce late take-offs Economy vs Business class passengers Healthcare applications tracking wheelchairs, etc

Document Tracking Commercial in Confidence Planed Application Demonstrations Ability to locate large number of files to desk level resolution across large office areas. We expect to carry out a trial with our prototype system in these areas over the next 0-3 months.

RF Processing Commercial in Confidence Reader System Architecture Tx Rx Co-ax cables Impinj Indy Chip Tx Rx Tx Impin j Tag Impin j Tag Impin j Tag Impin j Tag Tag Rx Tx coverage area Rx Reader reader has been developed based on Impinj Indy chip

(m) (m) Probability of failed reads Commercial in Confidence Coverage Performance Probability of failed reads (m) Conventional system with several read failures due to RF signal fading (m) NEW system with error free performance due to intelligent RF signal processing Currently, an error free (no failure in over 1 million attempts) passive system is demonstrated with 192 tags in ~1 second over a 10 m by 4 m area

Commercial in Confidence Pilot Studies I Paper tags Reader tag Concrete Pillar Four antennas are distributed over a 10 m x 8 m office area 115 tags are placed on desks

Commercial in Confidence Read Success Rate of 115 Tags over a 10m x 8m Office Conventional system <60% read success rate New system with 100% success rate Successfully read tag Null location

(m) Commercial in Confidence Pilot Studies II Large Area Reading of Metal Tags 20 15 Reader tag 10 5 0 0 5 10 15 (m) Four antennas are distributed over a 20 m x 15 m hall 11 on metal tags are placed on assets

(m) (m) Commercial in Confidence Read Success Rate of Metal Tags over Large Area 20 20 15 15 10 10 5 5 0 0 0 5 10 15 0 5 10 15 (m) (m) Conventional system <50% read success rate New system with 100% success rate Successfully read tag Failed read location

Commercial in Confidence Cambridge Solutions By using the Cambridge patented technology, integrated solutions are now possible for passive tracking over large areas 20 m x 20 m demonstrated to date Error free detection accuracy (100%) Accurate real-time location coverage (with sub-metre resolution) Capable of scaling to a large building, giving accurate RTLS coverage Installation is flexible to meet customer needs