A VHF Based Low Cost Solution for Tsunami Early Warning System, Sri Lanka

A VHF Based Low Cost Solution for Tsunami Early Warning

System, Sri Lanka

Project ID: Supervisors: Date:

▪Client : Disaster Management Center Sri Lanka

▪Requirement :Develop a system to monitor and

control early warning towers

▪Hardware and Software Solution

4th Year Project 15-105 2

Introduction

IntroductionPrevious work with DMC

▪Wireless Notification System Using

MANET with QOS-Support

▪QoS Enhancement of AODV in MANET

Based on Location Information


▪Early Warning Mechanism

▪Mass Media (TV / Radio)

▪EW towers

▪SMS

▪DMC operate 77 EW Towers

▪Operate via VHF

▪Play warning message repeatedly


IntroductionBackground

IntroductionSignificance of EW Towers

▪Area coverage

▪Congestion free communication

▪Communicate in unconventional

hours


IntroductionCurrent Deployment

▪American Signal Corporation

▪Communicate via

▪VHF radio

▪Satellite link


IntroductionDrawbacks of Current System

▪Vendor proprietary

▪Closed system

▪Software and hardware tightly integrated

▪Lack of support

▪Hardware failure require replacement

▪8 million per year


IntroductionRequirements

▪Low cost

▪Vendor Independent

▪Communication Using VHF

▪Simple Control Interface

▪Centralized Command Center to Control EW

Towers

▪Open system to Support Future Development


System ImplementationCurrent System


Singapore

Satellite

Transceiver

Station

Tower

Satellite Link

Satellite

Link

VHF Link

CSC 960

Base Station

CompuLert Software

System ImplementationProposed System


Tower

VHF Link

Base Station

VHF Radio

VHF Radio

Hardware module

Hardware module

Web Interface



Hardware module

Will be responsible for

• Executing functions like activating sirens.

• Manipulate the VHF Link.

• Encoding and decoding VHF messages.

• Handle stateful communication by using a

simple message structure.

• Generating overall system status logs.

• Generating event logs.

• Provide system interface to the

users.(Base Station side)



Web Interface

Will give users the ability of

• executing functions like activating sirens.

• Check status of the system.

• Generate Reports.

and some other functionalities.

Web interface of the proposed solution will

implement functionalities of the existing

“CompuLert” software.

VHF ModulationDTMF (Dual Tone Multi Frequency)

▪DTMF (Dual Tone Multi Frequency)

▪Signaling system to communicate between telecommunication equipment.

▪Support 16 characters

▪Character represent by two frequencies

▪80ms between character


VHF ModulationMorse Code

▪ Earliest form of radio transition

▪ Characters represent by combination of two audio

tones

▪ Support alphanumeric characters

▪ Transition time depend on unit time

▪Dot – one unit

▪Dash – three units


VHF ModulationAudio FSK

▪ Design to transmit digital data over a voice network

▪ Digital data is represented by changes in the

frequency (pitch) of an audio tone

▪ Support ASCII characters

▪ VHF/UHF maximum 1200bps

▪150 characters per second


VHF ModulationEncoding / Decoding


▪Encoding

▪Merging separate tones to create message

▪Using S/W library function

▪Decoding

▪FIR filter bank

▪Goertzel algorithm

Selecting the Control Unit

Raspberry Pi 2.0 Arduino Due Beagle Bone Black

Processor (Clock

Speed)

900MHz Quad Core 84MHz 1000MHz

Memory 1GB 96KB 512MB

Flash Micro SD Card Slot 512KB 4GB

USB 4 2 micro 2

Operating Voltage 5v 7-12v 5v

Network Interface Ethernet port - Ethernet port

Operating System Windows 10 / Linux - Linux

Size 86 x 56 x 20mm 101.52 x 53.3mm

Weight 45g 36g

Price $37.58 $38.59 $89


Selected Control Unit : Raspberry Pi 2.0

MethodologyWork Flow


12/20 1/10 1/31 2/21 3/14 4/4 4/25 5/16 6/6 6/27 7/18 8/8 8/29 9/19

Requirement Gathering

Literature Survey

Information Gathering

Analysis

Purchasing Resources

Designing of HW & SW

SW/HW Implementation

Program testing

System Implementation

System Testing

Improvements

Final Testing

Release version

Project Timeline

Duration

MethodologyWork Division


Member: Nadeendra

VHF Communication

Creating a message format

Topology implementation

Conversion of message

Modulation & demodulation of VHF signal

Member: Sachin

Control Software

Issue commands

Control towers

Handle communication

Status of towers

Member: Janaka

Base station module

Maintain the connectivity with the towers

Encoding the transmitting signal

Maintaining the database

Interface with the VHF radio

Member: Piyum

Tower module

Maintain the connectivity with base station

Interface with the VHF radio

Decoding the received signals

Functionality of sirens

Reference

▪ Raspberry Pi Foundation, "http://www.raspberrypi.org/products/raspberry-pi-2-model-b/," Raspberry Pi Foundation, [Online]. Available: http://www.raspberrypi.org/products/raspberry-pi-2-model-b/. [Accessed 4 March 2015].

▪ Arduino.cc, "Arduino Due," Arduino, [Online]. Available: http://arduino.cc/en/Main/arduinoBoardDue. [Accessed 4 March 2015].

▪ http://beagleboard.org/, "BeagleBone Black," Beagle Boards, 9 March 2015. [Online]. Available: http://beagleboard.org/BLACK. [Accessed 11 March 2015].

▪ S.Sircar, "Memorial University," [Online]. Available: http://www.engr.mun.ca/~sircar/project1_files/dtmf.pdf. [Accessed 5 March 2015].

▪ International Telecommunication Union (ITU), "International Morse code," ITU , Geneva, 2009

▪ B. Watson, "FSK: Signals and Demodulation," WJ Communications, Inc., 2001.


Thank you


Any Questions ?

A VHF Based Low Cost Solution for Tsunami Early Warning System, Sri Lanka

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