Page 1 of 6
The ESSD 2022 Conference December 12, 2022, NPIC, Phnom Penh
-87-
ការបម្រុងទុកទំនាក់ទងសំរាប់គម្រោះធរមជាតិគកើតគ ើង គោយ
ភ្ន
ា
ក
់
ងារវ
ិ
ទយអា
ុ
ម
៉ា
ទ
័
រររ
ួ
បញ្
ច
ូ
លរានៃការគម្បើម្ាស់ឧបករណ៍ APRS
ក
ា
ង
ុ
ការតារោៃទីតាំង
Communication Back-up for Natural Disaster by Emergency Amateur
Radio Operator and Implemented using APRS as Location Tracker
Sok Oeun UNa*
, Kimtho POa
, Kosorl THOURNb,1
, Rathna PEC
b,2
, Seven SIRENc,1
,
Channareth SRUNc,2
a* Faculty of Mechatronic and Technology Information, Institute of Technology of Cambodia
a
Institute of Technology of Cambodia
b Department of Telecommunication and Network Engineering, Institute of Technology of Cambodia
c Faculty of Electronic, National Polytechnic Institute of Cambodia
a*
us.oeun@gmail.com
គសចកតីសគងេប៖ គ្រោះធម្មជាតិគឺតតងតតគ ើតមានគ ើងជាគ ៀងរាល់ឆ្នគាំៅគលើពិភពគោ ។ ្រគេសម្យចាំនួនដូច ួ ជា ជរ ៉ុន, ឥណ្ឌ
ូ
គនស៉ុ៊ី
និងហ្វ៊ីល៊ីព៊ីន ជាគ យៗ ើ ្តូវបានេេួល ងនូវគ្រោះធម្មជាតិតដលម្និ បានគិតេ៉ុ ម្៉ុនគោយសា កា ផ្លាស់រត
ូ
អាកាសធាត៉ុ។ គ្រោះធម្មជាតិបាន
រាំផ្ាិចរាំផ្លាញគហ្ោា ចនាសម្ព័នធនន្រព័នធេាំនា េ់ ាំនងគៅគលើដ៊ីដូចជា្រព័នធេូ ស័ពទ ្រព័នធអ៉ុ៊ីនធឺតណ្តជាគដើម្។ ន៉ុងកា ្សាវ្ជាវគនោះ កា
រ្ម្ុងេ៉ុ េាំនា េ់ ាំនងគឺ្តូវបានគលើ គ ើងសាំរារ្់ រតិរតត អាមា េ ័គៅគលើដ៊ី ន៉ុងអាំ ៉ុងគពលតដល គ្រោះធម្មជាតិតដលម្និ បានគិតេ៉ុ ជា
ម្៉ុន ជាម្ួយនិងកា គ្រើ្បាស់ Callsign និងវេិយទា៉ុ ់េងអាមា េ័ សាម្ញ្ញៗ។ APRS គឺជាឧរ ណ្៍សាំខាន្់ តូវបានគ្រើ្បាស់សាំរារ់ជា
្រពន័ ធតាម្ោនេ៊ីតាងាំ គោយដាំគណ្ើ កា ម្និ ចបាាំ ចភ្ជា រ់ ់ ្រពន័ ធអ៉ុ៊ីនធឺតណ្ត ឬ្រព័នធគសវ េូ ស័ពទនដគ ើយ។ ្រព័នធគនោះ្តូវបាន ចនាគ ើង
តច គចញជាព៊ី តផ្ន គឺ្រពន័ ធេេលួ ខ៉ុស្តូវគ្រោះធម្មជាតិ(DRS) និងសាាន៊ីយ៍្គរ់្គង់គ្រោះធម្មជាតិ(DSSC)។ DRS គឺ្តូវបាន ចនា
គ ើងសាំរារអា់ មា េ ័ចល័ត គដើម្បដ៊ី
ាំគណ្ើ កា រាល់ បាយកា ណ្៍េិនននយ័ និងពតមា៌ នគៅកាន់ DSSC ។ GPS គៅ ន៉ុង DRS គឺេេួល
េិនននយ័ េ៊ីតាងាំ ព៊ីGPS ផ្លា យ ណ្រ តដលដាំគណ្ើ កា តាម្ យៈ្ច I/O រស់ APRS គហ្ើយវអាចគដើ តួជាជា្រព័នធតាម្ោនេ៊ីតាងបាន ាំ ។
Abstract-A natural disaster is happening every year in the world. Countries like Japan, Indonesia, and the
Philippines are often effected by unexpected climate change. Unexpected natural disasters destroy the
landline, internet connection, and mobile communication systems infrastructure surrounding the disaster
areas. In this research, the communication backup is proposed for Amateur grounding operators during
unexpected natural disasters with simple Amateur Radio devices and Amateur callsign. APRS is the main
device is using for tracking systems without an internet or mobile network connection. This system is
designed in two parts, Disaster Response System (DRS), and Disaster Station System Control (DSSC).
The DRS site is designed for the Amateur mobile ground station to access all report data and message
information to DSSC. The GPS in DRS gets data location from the GPS Satellites' access to APRS via
I/O ports, it can act as an APRS Tracker.
Keywords: APRS; Disaster; Amateur Operator; GPS; Tracker; Emergency
* អន និពនធេេលួ រនទ
៉ុ (Corresponding Author)
a,* គរ ខជនរណ្ិឌត វេិាសាានរគចេ វេិា ម្ព
៉ុជា
a Director, វេិាសាានរគចេ វេិា ម្ព
៉ុជា
bសាស្ត្សាត ច យ តផ្ ន វសិ វ ម្េម ូ គម្នាគម្ន៍និងគណ្តគវ ើ ននវេិាសាានរគច េ វេិា ម្ព
៉ុជា
c សាស្ត្សាត ច យ ននម្ហាវេិាល័យគអ ិច្តូនិ ននវេិាសាានជាតិពហ្៉ុរគចេ គេស ម្ព
៉ុជា
Copyright ©2022. Published by NPIC. All rights reserved.
Page 2 of 6
The ESSD 2022 Conference December 12, 2022, NPIC, Phnom Penh
-88-
I. INTRODUCTION
Cambodia has suffered from floods and storms
[1] and other natural disasters. Recently year by
year floods can happen during heavy rains in
Cambodia and the floods mostly rise around the
lower Mekong River, Sap River (Tonlé Sap), and
the lower landscape areas. In an early October
2020 report from the National Committee for
Disaster Management (NCDM) [2] floods affect
over 240,000 people in 71 districts of 19 of the
country’s 25 provinces and autonomous regions.
At least 20 people have lost their lives.
The Early Warning System 1294 (EWS1294)
[3] installed 34 sites warms people in advance of
natural hazards occurring in Cambodia. When an
event such as flooding is detected or predicted, a
voice recording is sent to the mobile phones of
registered users in the areas at risk. EWS1294 has
127,964 registered users, 26 active sensors, and
2,572,211 Alerts sent [3]. EWS1294 works with 5
steps, 1-User Sign up (User dials free call 1294
and follows the prompts for registration), 2-Smart
Sensors, 3-Data Disseminated, 4-Warnings Sent,
and 5-Action Taken. Step 2 and 3, the smart
sensors send the acquired data across the internet
via the Cambodian cellular mobile phone network
as designed in this system. Step 4 and 5,
EWS1294 sends warning messages via the
interactive Voice Response (IVR) Platform and
the Action Taken step for user registration receive
calls via their mobile phones as same as mobile
services. EWS1294 works frequently with
smartphone devices and internet access to receive
warning information from the Provincial Centers
for Disaster Management (PCDM) to people via
their mobile phones and take appropriate action to
protect themselves.
During floods, landline telecommunication,
mobile phone repeater even internet access can
interrupt heavy flooding areas [4] or due to power
outages and damaged cell sites [5]. This problem
will happen during landline telecommunication
and mobile phone repeater infrastructures fully
destroy and disconnect. The cellular connection
system and internet access failed to occur to
EWS1294 deactivating warning messages and
voice not able to reach people via their cellular
phone. When the mobile phone system deactivates
a higher percentage of people cannot receive the
alert warning messages from the PCDM and
cannot call and report harmful floods with the
serious situation back to the PCDM or any
responsible stations to save their livelihoods. In
these situations, the people really need to recover
and activate their suitable connection to contact
the government for help or other responsible
operator stations to inform them that they were
alive and needed help.
II. RELATED WORK
A. Automatic Packet Reporting Systtem (APRS)
Recently, a lot of HAMs focuses on modern
system techniques to add to their operation for
more easily use Automatic Packet Reporting
System (APRS). APRS as shown in Fig. 1, which
was designed by Bob Bruniga (callsign:
WB4APR), is a packet communication protocol
for exchanging real-time tactical information to
everyone in a shared RF environment [6] and
APRS also use for tracking systems [7]. In this
research, backup communication for a natural
disaster by emergency amateur radio operators
proposes to build the Amateur grounding system
(ground-space-ground) with an APRS Amateur
transceiver, and Amateur Satellites. In this APRS
application as the Automatic Package Report,
share location to other environment RF devices,
and weather stations.
Fig. 1 APRS
In this work, the objectives are implementing
the APRS system with traditional Amateur
Operator use. The APRS is the most important
role to become the iGat when connecting to the
network/ Internet via the RJ45 port, it becomes a
Digipeater when disconnect from the network but
connects to radio devices, and it becomes a BT
TNC when connect to an iOS/Android app
(APRSDroid or others) [8] via Bluetooth, it
becomes the GPS when connecting to a TTL/RS- 232 (jumper selectable)-it can act as an APRS
Tracker, and it can read sensors and becomes a
weather station (WX) without the need of a
computer. This system is a proposed backup
system via the Amateur operator with APRS. The
APRS becomes the Digipeater that is accessed
Page 3 of 6
The ESSD 2022 Conference December 12, 2022, NPIC, Phnom Penh
-89-
from APRS grounding to the APRS-Satellite
digipeater and any Amateur Satellite (AMSAT)
[9] builds with a digipeater in the space orbit.
B. Amateur Satellites and Tracking System
Software
This system is worked friendly with Amateur
Radio between grounding to grounding and
grounding to space. In this case, the system
combined two ways of communication, the
Amateur grounding station operator communicates
with other Amateur grounding stations, and from
Amateur grounding station link to the AMSAT.
The full system is worked from grounding with
low power consumption, a simple homemade Yagi
Dual Band with 3-element and 6-element Yagi- Uda antenna with frequency rang 29.4815
MHz/145.900 MHz for uplink and 435.350
MHz/435.690 MHz for downlink suitable used for
any type of AMSAT or PSAT2 APRS CubeSat
[10] downlinks frequency 435.350 MHz PSK31
and SSTV - 145.825 MHz for telemetry, APRS
and DTMF/voice, uplink frequency 29.4815 MHz
SSB PSK31, SSTV - 145.825 MHz for APRS and
DTMF Grids/msgs. Transceiver 7 watts Dual
Band VHF/UHF transceiver (mobile station),
YEASU FT-897 all-mode transceiver (fixing
station), and modern MCU-Raspberry pi to access
the telemetry type to APRS. Ham could report
their automatically location via the GPS tag with
APRS to any response stations when the system
could not communicate between ground-to-ground
or ground-to-space satellites. Sharing location
could see in the smartphone that is connected to
the APRS device via Bluetooth network and
APRS iGate from the server application
APRSDroid or accessed through the website
aprs.fi [11].
This is enough to make sure where satellite fly
over this system and ready in the satellite footprint
coverage area. The main satellite tracking system
is used Orbitron [12], software for satellite
tracking system. This software was not much
friendly use if compared to Gpredict [13] as shown
in Fig. 2, Satellite Tracking System-GUI
determined satellite’s information, footprint,
speed, angle, and real time fly over the back-up
communication system grounding.
Fig. 2. Gpredict satellite tracking system-gui
grounding set in Cambodia
C. Amateur Radio Operator
Amateur Operator mostly call Ham, a group
who is response in disaster activities. Recently,
Cambodia don’t have more locally Amateur
operator for any disaster help. To become a Ham,
they need to hold the FCC license [14] to clarify
about their experiences and about Radio systems
knowledge. For getting these licenses, the
candidates must pass the examination, technical
level, General level, and Extra level. To verify in
the exam at least three examiners who has a
general and extra license holder. In the testing
XU7AKM is used for local callsign in Cambodia
and KE0SOY is used for international callsign.
III.METHODOLOGY
A. Mobile and Response station design
In this research the back-up communication is
proposed for Amateur grounding operator during
unexpected natural disaster. APRS is the main
devices which are used for back-up
communication system. This system was designed
in two parts, Disaster Response System (DRS),
and Disaster Station System Control (DSSC) as
illustrated in Fig. 3. The DRS site is designed for
Amateur mobile ground station to access all report
data and message information to DSSC. The GPS
in DRS was for getting data location from the GPS
Satellites connected to APRS via I/O ports, it can
act an APRS Tracker. DSSC responses the
message and data information from DRS accessed
to the server and shared those data information to
devices that are connected to the internet access.
The mean, APRS became an iGate when
connected to the network/Internet via the RJ45
port that is allowed the smart devices could
connected and get all data information from DRS