elit pel-1000 rtls proposal

유비쿼터스 컴퓨팅 데이터베이스 연구실

Ubiquitous Computing Database Lab

eLIT RTLS for port logistics (Business proposal)

Last update: March 18, 2013

eLIT Co., Ltd.; PNU, Republic of KOREA


Ubiquitous Computing Database Lab㈜일리트

Proprietary & Confidential ( 무단전제 /복제 금지 )

Overview

Target Objects for real time location tracking Current phase

Y/T (Yard Tractor) or AGV (Automated Guided Vehicle) C/C(Container Crane), T/C (Transfer Crane)

Future Containers

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Overview

RTLS : Real-Time Locating System Tag/Reader/Locating Engine

3

Internet Intranet

GUI Application

RTLS engine

RTLS tag

UDP / TCP

UDP

RTLS reader




Overview

Method for locating The method of location is through identification and location

Amplitude Triangulation (RSSI : Received Signal Strength Indication) Time of Flight Ranging Systems(TOA, TOF) Time Difference of Arrival (TDOA)

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(x1,y1) d1

d2

d3

(x2,y2)

(x3,y3)

(x1,y1) (x2,y2)

(x3,y3)

r1 – r3 r1 – r2

Triangulation Hyperbolic location estimation




Overview

Method of distance measurements

RSSI : Radio signal strength Indication Measuring Radio signal strength Radio signal attenuates exponentially

RSSI ∝

TOA/TDOA Measuring speed of RF(radio frequency)

299,792,458 m / s = .33m / ns

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Sender Receiver

Ptx Prcvd

d

nd

PSd: distance

n ∈ [−2, −0.1]

PS: the sending signal voltage

40% signal strengthvariation with angle

0 10 20 30 40 50 60 70 80 90 10011050

100

150

200

250

300

350

400

450

RS

SI

Distance(m)




Overview

Comparison of RF distance measuring techniques

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RSSI TOA TDOA

Accuracy inaccurate accurate accurate

Maximum range<100m

(<30m)

>100m

(>km)>100m

Time Synchronization

x Reader-tag Reader-reader

Tag simpleComplex

Power consuming

simple

Cost Low High Moderate

Main applicationIndoor

application

Global/City-scale

application

Outdoor application




Motivation

Motivation of RTLS development Real-Time Locating System(RTLS)

Port application needs more precise locating system Required precision error : < 3m

=> TOA/TDOA based RTLS

Container terminal environments Reader installation : top of light tower

Not 2-D environment Severe RF Shadow area on densely stacked container yards

Major vendor reports their big location error (>20m)

=> application specific optimization techniques for RTLS

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Light tower

Reader




Motivation

Pilot Project for RTLS

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Ubiquitous Computing Database Lab


H/W Layout

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15dB Omni-directionl *1 EA

6.5dB Diversity directional *1 EA

15dB Omni-directionl *2 EA





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RTLS readers on light tower





Y/T: (RTLS Tag)

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12

370m

350m

120m

Location AccuracyLocation Accuracy

RTLS reader’s interval: : 100~150m

BICT: 20m – 30m error




RTLS for port logistics

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RTLS Project Objectives

Real Time Locating System for port logistics

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14




IEEE802.15.4a RF

Ranging Method TWR ( Two-Way Ranging )

Two-way Ranging Using round-trip time (RTT) Do not need time-synchronization

RF encoding CSS ( Chirp Spread Spectrum )

Robust against disturbances Robust against multipath fading

Using CSS-TWR ranging mechanism

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RTLS-Tag

Features MCU :TI MSP430F2272

Flash Memory : 32KB + 256B RAM : 1KB

RF chip : Nanotron NA5TR1 IEEE802.15.4a

Size : 50(L) x 40(W) x 15(H) mm3 Communication range : up to 300m Lifetime : about 2 years

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<vehicle> <human>




RTLS-Reader

Features Main processor : Intel PXA255 (400MHz) RF control processor: STM32F103 (72MHz Cortex-M3) Quad RF module

Use 4 directional antennas

10/100Mbps Ethernet UDP/TCP communication

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RTLS Locating Engine

Position estimation using Linear Least Square Include Data Filtering module 2.5D Location calculation

Port logistics environment is not 2D Height of Light tower : 30m-40m

Our approach Convert 2D location data into 2.5D

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Scalable RTLS

Conventional RTLS system Server(Engine) overload

OUR APPROACH : Embed RTLS server function into Readers Effective load balancing Fault tolerant

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Scalable RTLS

System Diagram

- 20 -




Assistant tag approach

Assistant tag approach to overcome radio shadow area The tag assists estimating distance for locating acting as a virtual reader

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RTLS Testbed

Testbed in PNU Stadium

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0

2000

4000

6000

8000

10000

12000

0 2000 4000 6000 8000 10000 12000




RTLS Construction

Korea Gwangyang port

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RTLS Construction

Korea Hutcheson Port

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RTLS Construction

Koea Hyundai New Port

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Conclusions

Conclusions LIT-RTLS : RTLS system for port environments

Full system develpment RTLS tag RTLS Reader RTLS engine

New ideas for port environment Assistant tag method to overcome RF shadow area Distributed RTLS server

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elit pel-1000 rtls proposal

Documents