AFC Forum C1: Environmental Remote Sensing, The 21nd CEReS International
Symposium and The 2nd Symposium on Microsatellites for Remote Sensing (SOMIRES
2014)
Time: Friday, 22 August 2014: 2:00pm – 3:30pm
Session Chair: Josaphat Tetuko Sri Sumantyo, Chiba University, Japan
Location: Baris Room, Inna Grand Bali Beach Hotel
Language: English
The 2nd Symposium on Microsatellites for Remote Sensing (SOMIRES 2014) has been
held at Sanur, Indonesia on 22 August 2014 to discuss the progress of our microsatellites
project with nine invited talks. This symposium was collaborating with The 2nd Asia
Future Conference (AFC 2014) as AFC Forum C1: Environmental Remote Sensing and The
21th CEReS International Symposium 2014. This symposium was attended by about 60
participants.
Session Abstract
Recently, global environment changes caused by human activities, natural disaster etc.
Remote sensing technology is very important tool to observe the environmental change.
This session will discuss remote sensing technology and applications, especially sensor,
unmanned aerial vehicle, microsatellite, image analysis and applications etc.
近年、人間活動、自然災害などによって、アジア地域をはじめ、世界各国に環境変化が起きている。この環境変化を監視するために、リモートセンシング技術が欠かせないツールである。本セッションでは、リモートセンシング関連のセンサ、
無人航空機、小型衛星、画像処理と応用などを議論する予定である。
Bali, 22 August 2014

Prof. Josaphat Tetuko Sri Sumantyo, Ph.D
General Chairman

Abstract Collection

Microwave Remote Sensing for Environmental Monitoring
Josaphat Tetuko Sri Sumantyo
Chiba University, Japan; jtetukoss@faculty.chiba‐u.jp
Abstract :Synthetic Aperture Radar (SAR) is well‐known as a multi‐purpose sensor that can be
operated in all‐weather and day‐night time. In this research, we propose Circularly
Polarized Synthetic Aperture Radar (CP‐SAR) or Elliptically Polarized Synthetic Aperture
Radar (EP‐SAR) onboard unmanned aerial vehicle (UAV) and microsatellite to retrieve
the physical information of land surface and disaster monitoring. The sensor is designed
as a low cost, light, low profile configuration to transmit and receive left‐handed circularpolarization (LHCP) and right‐handed circular polarization (RHCP). For this purpose, wedevelop UAV JX series for ground experiment of this sensor. The main mission of CP‐SAR
is to hold the basic research on elliptically polarized scattering and its application
developments. In the basic research, we will investigate the elliptical (including circularand linear polarizations) scattering wave from the land surface, generation of axial ratio
image (ARI), ellipticity and tilted angle images etc. We will hold the analysis andexperiment of circularly polarized wave scattering on vegetation, snow, ice, soil, rock,sand, grass etc to investigate the elliptical scattering wave. CP‐SAR sensor transmits only
one polarization, RHCP or LCHP, then this sensor will receive RHCP and LHCP scatteringwaves simultaneously. The image is employed to investigate the relationship between
the physical characteristics of vegetation, soils, snow etc. The image of tilted angle as the
response of land surface also will be extracted to mapping the physical information of
the surface. In application development, CP‐SAR sensor will be implemented for land
cover mapping, disaster monitoring, Cryosphere monitoring, oceanographic monitoring
etc. In disaster monitoring, CP‐SAR sensor will be employed for monitoring ofearthquake area, volcano activity, landslide etc. This paper introduces progress ondevelopment of our CP‐SAR onboard UAV and microsatellite, including the applications.

Scope of Asian Micro‐satellite Consortium with Super‐
constellation
Yukihiro Takahashi
Hokkaido University, Japan; yukihiro@mail.sci.hokudai.ac.jp
Abstract :Micro‐satellite with a weight of 50‐100 kg has a great potential with various merits
compared to larger sized satellite, that is, 1) very low cost development, that is, around
5 M USD including BUS and mission payloads. The launch cost will be about 3‐5 M USD
as piggyback or assembling launch, 2) quick fabrication in two years for flight model,
enabling application of the latest technologies, 3) on‐demand operation, taking detail
information at a point of interest, and 4) the low cost and quick fabrication make us
possible to launch not a small number of satellites, which is called as “constellation”
flight. If we have a budget for one large satellite, it’s possible to fabricate and launch 50
or more micro‐satellites. Here we suggest the international organization, “Asian micro‐
satellite consortium” (AMC), which promotes and accelerates the micro‐satellite
development and the discussion of data utilization. AMC will consist of domestic working
group in each country. The each working group is composed of 3 parts: BUS development
team, payload development team and data user team, involving various field scientists
or engineers, such as forestry, agriculture, fishery, forest fire, bio‐diversity, flood,
meteorology, climate change, ionospheric / magnetospheric science, etc. Also in AMC
we will discuss the possibility of future projects, such as “on‐demand operation” or“super constellation” involving more than tens of micro‐satellites and unmanned air
vehicles (UAVs) under international collaboration. At this moment, institutes/universities
in about 10 countries in SE‐Asia show strong interest in that collaboration.

Observations of Ionosphere with Mini/Microsatellites –Problems and Solutions‐
Koichiro Oyama
National Cheng Kung University, Taiwan and Kyushu University, Japan;
koh_ichiro@yahoo.co.jp
Abstract :DC Langmuir probe is one of the key in‐situ instruments to study ionosphere. It needs acounter electrode whose conductive surface area is at least 1000 times larger than thatof surface area of the electrode. This requirement is usually fulfilled for large satellites
which have been launched so far for ionosphere study. Now we are jumping into an era
to use tiny satellites. Then we will encounter serious problems if we try to use DC
Langmuir probe. One of the problems is related to a small ratio of conductive surfacesof counter electrode to that of the electrode. The second serious problem is associatedwith contamination of electrode as well as satellite surface. These two factors make it
impossible to use DC Langmuir probe as an instrument of tiny satellite. We review
problems which appear for the ionosphere measurement by using tiny satellites, andpropose ways avoid the problems to accomplish accurate measurements.

Development of Space‐based Magnetic Activities Measurement
Mission in LAPAN’s Micro‐Satellites
Robertus Heru Triharjanto1, Harry Bangkit 2, M. Arif Saifudin 1
1 Center for Satellite Technology, LAPAN, Indonesia; 2 Center for Space Science, LAPAN,
Indonesia; rtriharjanto@yahoo.com
Abstract :LAPAN has been observing space weather data using ground‐based sensor, among
others magnetometer. With the develoment of micro‐satellite technology in LAPAN, it
become possible for LAPAN to have space‐based magnetometer. The paper elaborate
the mission concept of the payload, and the development progress that has been doneto achieve the mission objectives. The learning process done on the satellite‐basedmagnetometer data handling at the Center of Satellite Technology and Center for Space
Science was started with the data handling of magnetometer in attitude control system
of LAPAN‐A2 micro‐satellite. With such knowledge, the specification and the test
procedures of magnetometer that will be on‐board of LAPAN‐A3 and LAPAN‐A4 micro‐
satellite was defined. The paper also discuss further planning that was drawn for thedevelopment of more scientific class geomagnetic measurement mission in LAPAN‐A4
micro‐satellite.

Development of a Ground‐based Synthetic Aperture Radar forLand Deformation Monitoring
Voon Chet Koo 1, Tetuko Sri Sumantyo Josaphat 2, Tien Sze Lim 1, Yee Kit Chan 1, Habibah
Lateh 3
1 Multimedia University, Malaysia; 2 Chiba University, Japan; 3 Universiti Sains Malaysia,
Malaysia; vckoo@mmu.edu.my
Abstract :Every year, over one million people are exposed to weather‐related landslide hazards
around the World. Due to the recent climate change, it is likely that the decrease ofpermafrost areas, changes in precipitation patterns and increase of extreme weather
events will influence the weather‐related mass movement activities. This paper reports
the recent development of a ground‐based synthetic aperture radar (GBSAR) for
continuous monitoring of landslide‐prone areas in Malaysia. It is an ultra‐wideband
system operating at 17 GHz with spatial resolution of 0.3 m in range and 5.8 mrad incross range. The system is mounted on a rail which travels along a linear guide to achieve
SAR imaging. The GBSAR has been installed at a test site to provide timely information
for landslide monitoring and early warning system. The paper discusses the design,development and field experiments using the new GBSAR system.

The challenge for still unresolved development of Multi‐band
Equatorially Orbiting POLSAR satellite sensors – an integral task
for the major space‐SAR technology centers world‐wide –focused on the Indonesian Islands Environment
Wolfgang‐Martin Boerner
University of Illinois at Chicago, United States of America; wmb1uic@yahoo.com
Abstract :We need to mobilize and draw full responsible attention of the main SAR Development
Centres worldwide such as NASA/JPL, ESA/ESTEC, JAXA/EORC, CSA/SAR, DLR/SAR,
DSTO/SAR,
ISRO/SAC,
INPE/SERE
plus
NTU‐Temasek,
NCU‐CSRSR,LAPAN/RANCABUNGUR, and so on; joining forces and strongly contributing to a viablemulti‐band general bi‐static (including cross/along)‐track POLSAR sensor technology,
well suited for equatorial monitoring within orbits of +/‐ 20* latitude. Then, local regions
such as the Indonesian islands could be observed daily up to 12 to 14 times, coveringboth the land and ocean regions essential for environmental protection andmeteorological forecasting, respectively, on a hitherto unprecedented global level. With
the relentless increase in population density, the anthropogenic expansion into natural
terrestrial hazard zones has become irreversible resulting in ever more catastrophic
disasters, not only in the Asia‐Pacific region more so within the entire tropical belts
engulfing Mother Earth. Thus not only the Indonesian‐Pacific Islands, so also SouthAmerica, Africa and back via the Indian Ocean Islands to Asia‐Pacific, these natural
events like volcano eruptions, earthquakes with emerging tsunami, cyclones and severe
down pours have caused havoc, loss of lives, destruction of infrastructure and above allintentional manmade interference resulting in the deterioration of pristine tropicaljungle forests. What is required is around‐the‐clock local and wide‐area surveillance andremote sensing of the vegetative cover for which first well designed optical equatoriallyorbiting satellite sensors had been developed but their successful implementation failed
because of the ever increasing cloud, precipitation, humidity and aerosol cover within
the entire equatorial belt of +/‐ 15* ~ 20* latitude rendering penetration at optical
wavelength mostly ineffective. Hence, we must take recourse to microwave sensing, andimplement radar and synthetic aperture sensors from air and space operational at day& night independent of weather; and the sensors especially suited are the fullypolarimetric POL‐SAR sensors developed for satellite remote sensing by the major SAR
technology development centers worldwide. As first and main test case, we will explore
the Indonesian Island region.

The plan for space observation network installation in Southeast
Asian region
Tu Hwan Kim, Sung Ho Na, Seoung Yong Kang
Ajou University, Korea, Republic of (South Korea); thkim@ajou.ac.kr
Abstract :In the near future, after spread of the small SAR satellites in Southeast Asian region, eachcountries will install small ground stations for receiving satellite data. If the groundstations will be equipped with a broadband (2～14 GHz) receiving system, they may be
used as VGOS (VLBI Geodetic Observing System) station. In other words, it is possible todo VLBI (Very Long Baseline Interferometry) observation with a main station which has
a 20 m class antenna equipped with broadband receiving system. And then it can beused for multiple purposes, such as resource exploration, crustal deformation,
monitoring of natural disasters and so on.
On the other hand, there is no geodetic VLBI observation networks in Southeast Asia,and they do not use the World Geodetic System (WGS), which is adopted worldwide. To
use the WGS, one should determine accurately the reference origin of each the country,
and then build its local reference coordinate system. For this purpose, after installing thegeodetic VLBI observation station, it is necessary to accurately determine the reference
point of the observation station. In this way we can build the new national reference
coordinate system based on the WGS. To perform the geodetic VLBI observation thereof,
we should construct the international joint, space observation network with small
ground stations and the hub observing station with a 22m antenna of Korea.
This paper discuss the multi‐purpose space observation network installation inSoutheast Asian region.

Image Quality Comparison of Linear Polarized and Circular
Polarized SAR
Heein Yang 1, Bambang Setiadi 2, Josaphat Tetuko Sri Sumantyo 2, Jae‐Hyun Kim 1
1 Ajou University, Korea, Korea, Republic of (South Korea); 2 Chiba university, Japan;
jkim@ajou.ac.kr
Abstract :Synthetic Aperture Radar (SAR) is recognized as a powerful surveillance and land
observation purpose system these days. An SAR sensor is usually loaded on moving
platform such as aerial vehicle or satellite then acquires the images of remote area ininterest. Also this system uses microwave for its own illumination source, therefore it
can be operated regardless of the weather condition. When SAR system performs its
mission in space, there are ionosphere and air in the path of satellite and the target as apropagation medium. Conventional SAR system uses linearly polarized (LP) microwave
and as LP wave traverses through the ionosphere, Faraday rotation (FR) effect occurs. FR
makes the reference plane of microwave tilt slightly, consequently causes polarization
mismatch when receiving the backscattered signal. This polarization mismatch
eventually degrades the image quality such as image burling, degradation of contrast,
and etc. To cover up the problems of conventional LP‐SAR system, this paper proposesthat circularly polarized (CP) SAR system which can get rid of polarization mismatchtheoretically and compare the pros and cons between LP and CP SAR images withsimulated image data.

International cooperative studies on environment and disastermitigation with satellite remote sensing
Fusanori Miura
Yamaguchi University, Japan; miura@yamaguchi‐u.ac.jp
Abstract :The center for Remote Sensing and Ocean Science (CReSOS) was established with theaid of JAXA and LAPAN in Udayana University (UNUD) in 2003. Objectives of CReSOS are:i) to educate graduate school students for environment studies such as research on
climate change and oceanography, coastal environment & fishery, land process andprecipitation, mechanism of natural disasters and its effects on human society etc., ii) to
set up and maintain Indonesia ocean data archives, iii) to promote international
cooperative research between UNUD and Japanese research institutions, iv) to be anational node for remote sensing research through these activities. JAXA PILOT PROJECT
was started in 2003 and continued until 2008. UNUD and Yamaguchi University (YU) has
established joint master course program in 2009 with the support of Grant from
Government of Japan for International Graduate School Cooperation by Satellite
Remote‐Sensing. Then UNUD and YU started double degree program in 2011. Some
UNUD students come to YU and study in the second academic year and some of thementer Doctoral course and acquire PhD. Many valuable papers have been publishedthrough the program. The program is now expanded not only for Indonesian students,
but also for students in Southeast Asia countries.

Paper Collection

MICROWAVE REMOTE SENSING FOR ENVIRONMENTAL MONITORING
Josaphat Tetuko Sri Sumantyo
Center for Environmental Remote Sensing, Chiba University
1-33 Yayoi, Inage, Chiba 263-8522, Japan
Email jtetukoss@faculty.chiba-u.jp Website : http://www2.cr.chiba-u.jp/jmrsl/
ABSTRACTThis paper introduces the progress of circularly polarized
synthetic aperture radar (CP-SAR) development in Center
for Environmental Remote Sensing, Chiba University, Japanfor unmanned aerial vehicle (UAV, JX series) andmicrosatellites (GAIA series). This sensor will be used tomonitor global land deformation and disaster area.
Index Terms— CP-SAR, Synthetic Aperture Radar,
UAV, Microsatellite
1. INTRODUCTION
Synthetic Aperture Radar (SAR) is well-known as amulti-purpose sensor that can be operated in all-weather andday-night time. As our laboratory roadmap for
microsatellites and unmanned aerial vehicles development(refer Fig. 1 and Fig. 2), our laboratory develops Circularly
Polarized Synthetic Aperture Radar (CP-SAR) or
Elliptically Polarized Synthetic Aperture Radar (EP-SAR)
to retrieve the physical information of land surface anddisaster monitoring. The sensor is designed as a low cost,light, low profile configuration to transmit and receive lefthanded circular polarization (LHCP) and right-handed
circular polarization (RHCP), see Fig. 3. For this purpose,
we also develop unmanned aerial vehicle (UAV) for groundexperiment of this sensor [1]-[2], see Fig. 4 and Fig. 5
The main mission of CP-SAR is to hold the basic
research on elliptically polarized scattering and its
application developments. In the basic research, we will
investigate the elliptical (including circular and linear
polarizations) scattering wave from the land surface,
generation of axial ratio image (ARI), ellipticity and tilted
angle images etc. We will hold the analysis and experimentof circularly polarized wave scattering on vegetation, snow,
ice, soil, rock, sand, grass etc to investigate the ellipticalscattering wave. These images will be extracted by using thereceived RHCP and LHCP wave. CP-SAR sensor transmits
only one polarization, RHCP or LCHP, then this sensor will
receive RHCP and LHCP scattering waves simultaneously.
The image is employed to investigate the relationshipFig. 1. Road map of Microsatellite development

Fig.2. Roadmap of UAV development
between the physical characteristics of vegetation, soils,
snow etc. The image of tilted angle as the response of land
surface also will be extracted to mapping the physicalinformation of the surface, i.e. geological matters, contour,snow-ice classification, vegetation characteristics etc.
In application development, CP-SAR sensor will be
implemented for land cover mapping, disaster monitoring,
Cryosphere monitoring, oceanographic monitoring etc.

RF System

SAR Processor

CP-SAR System

RX Antenna

TX Antenna

Fig. 3. Circularly Polarized Synthetic Aperture Radar (CPSAR) and antenna for Josaphat Laboratory Experimental
Unmanned Aerial Vehicle (JX-1)

Fig. 4. Flight test of CP-SAR onboard UAV JX-1 at
Fujikawa Airport, Japan on 29 August 2013.

Especially, land cover mapping will classify the forest andnon-forest area, estimation of tree trunk height, mangrove
area monitoring, Arctic and Antarctic environment
monitoring etc. In disaster monitoring, CP-SAR sensor will
be employed for monitoring of earthquake area, volcano
activity, landslide etc. This paper introduces progress ondevelopment of our CP-SAR onboard UAV JX-1/JX-2 andmicrosatellites.
2. CP-SAR ONBOARD UNMANNED AERIALVEHICLE (UAV)The CP-SAR onboard UAV (Fig. 6) is mainly composedby Flight Control System, Telemetry and Command Data
Handling, Attitude Controller, and Sensors. Telemetry andCommand Data Handling subsystems use S-bandcommunications between UAV and ground station. Attitude
Controller is composed by Inertial Measurement Unit
(IMU) and GPS units. Sensors are composed by CP-SAR asmain mission sensor, and other sensors. CP-SAR subsystem itself is composed by chirp pulse generator module,
Transmitter and Receiver (Tx-Rx) module, and Image
Signal Processing module. Ground control segment wasused for CP-SAR sensor monitoring and image processing.
The CP-SAR system is composed by transmitter andreceiver sub modules.

Fig. 5. The 2nd Josaphat Laboratory Experimental
Unmanned Aerial Vehicle (JX-2) for microwave sensor
ground test
The input of transmitter is In-phase (I) and Quadrature (Q)signal of chirp pulse generated by pulse generator withbaseband range is DC to 150 MHz (normally 50 MHz).
Then chirp pulse is modulated by frequency 1,270 MHz,
where our Tx-Rx system has frequency range 1270 MHz±50 MHz (maximum ± 150 MHz). The transmission system
has gain tuning function as 1, 2, 3, 8, 16 dB or 0 to -31 dB,
and receiver has gain tuning function as 1, 2, 3, 8 and 16 x 2
or 0 to -62 dB. Power amplifier (PA) is available to control
pulse transmission output power 50 W with pulse widthFig. 6. CP-SAR UAV System

LHCP

RHCP

Fig. 8. Modules of CP-SAR onboard microsatellite

GPS-RO

Fig. 7. CP-SAR onboard microsatellite
maximum 10 s, and maximum duty circle is 2%. The
switching speed of transmission and receiver systemantennas (RHCP and LHCP) is typically 1 s and maximum
2 s. The antenna is composed by two sets of CP microstrip
array antenna (LHCP and RHCP panels), totally 4 panels to
realize full polarimetric CP-SAR sensor. We could control
the pulse length and bandwidth of chirp pulse (max 150
MHz), and save data to SSD memory.
In this research, the CP-SAR onboard unmanned aerial
vehicle (CP-SAR UAV, Fig. 4 and 5) is developed forground testing of CP-SAR and other sensors. The platform
called Josaphat Laboratory Experimental UAV (JX-1 andJX-2) has 25 kg of payload availability for various
microwave sensors (CP-SAR, GPS-SAR etc) and optic
sensors, i.e. hyper spectral camera. The operation altitude is
1,000 m to 4,000 m. The specification of CP-SAR sensor
for UAV is center frequency 1,270 MHz, ground resolution
up to 1 m, pulse length could be tuned from 4.5 to 48 s,maximum pulse bandwidth 150 MHz, off nadir angle 30o to
60o, swath width 1 km, antenna size for 4 panels of CP-SAR
1.5 m x 0.4 m, PRF 1,000 Hz, and peak power 8.65W (1km) to 95W (4 km). We held ground experiment withaltitude less than 2 km with pulse transmission output power
50 W. The data retrieved by LHCP and RHCP antenna [3]is employed to investigate the characteristics of ellipticalpolarization, including circular and linear polarizations. In
the future, further investigation of characteristics of circularpolarization will be done by using our new CP-SAR UAV
JX-2.

Fig. 9. Power network of CP-SAR microsatellite
3. CP-SAR ONBOARD MICROSATELLITE
Fig. 7 and Fig. 8 shows model and main components of
CP-SAR onboard microsatellite that developed in Josaphat
Microwave Remote Sensing Laboratory (JMRSL), Center
for Environmental Remote Sensing, Chiba University. This
microsatellite is composed by Command and Data HandlingSub-system (CDS), Communication Subsystem (CMS),Electrical Power Subsystem (EPS), Altitude Control
Subsystem (ACS) and payload. CDS uses Leon3 card, lowpower supply card (LVPS), IO card, payload IO card, andnon-volatile memory card. CMS is composed by LVPS, lowpower supply card, S band transmitter & receiver (STX andSRX) and antenna for telemetry, X band transmitter andantenna for data downlink. EPS is composed solar panel,solar power regulator, power supply card, power
distribution card, Li-Ion battery pack and battery control
card. ACS employs LVPS, actuators (reaction wheels
assembly–RWA and electromagnetic torque bar-EMTB)
and sensors (coarse sun sensor-CSS and three-axis
magnetometer-TAM), and GPS Receiver-GPSR. Payload iscomposed by main sensor CP-SAR for Earth surface
monitoring and minor sensors: electron density –temperature probe (EDTP) for ionospheric monitoring.

Corner Reflector

Corner Reflector

CP-SAR System

CP-SAR System

Fig. 10. Ground test of CP-SAR system for UAV
Power network of our microsatellite is shown on Fig. 9. We
also develop SAR ground test measurement system asshown on Fig. 10 with moving precision 0.1 mm.
We also develop sub mission sensors, i.e. GPS-RO andelectron density – temperature probe (EDTP) to monitor
ionospheric phenomena. We will employs these ionosphericobservation sensors simultaneously with our CP-SAR tomonitor ionosphere and global land deformation. Therefore
we could mapping pre-cursors of earthquake by using our
microsatellites in the future. Fig. 11 shows experiment of
our EDTP in vacuum chamber to investigate theperformance in plasma environment.

Fig. 11. Electron Density – Temperature Probes (EDTP) testin vacuum chamber
ACKNOWLEDGEMENT
Josaphat Microwave Remote Sensing Laboratory (JMRSL)
thanks to Chiba University, the Japan Society for the
Promotion of Science (JSPS); Chiba University COE Startup Program; the Japanese Ministry of Education andTechnology (Monbukagakusho); JICA-JST SATREPS
Program, PASCO, Weathernews, Venture BusinessLaboratory – Chiba University etc for supporting thisresearch.

4. SUMMARYREFERENCES

In this paper, we introduce the progress of developmenton CP-SAR onboard UAV and microsatellite in ourlaboratory. The CP-SAR sensor is designed as small, lightin weight and low power consumption system. The CP-SAR
sensor is developed to radiate and receive ellipticallypolarized wave, including circularly and linearly polarizedwaves. In the near future, this sensor will be installed in our
UAV and microsatellite that will be applicable for land
cover mapping, disaster monitoring, snow cover andoceanography monitoring etc. We also develop someionospheric observation sensors that is introduced in thispaper too. In the future, these sensors could be employed forobservation of ionosphere and global land deformation
simultaneously for disaster monitoring and prediction.

[1] J.T. Sri Sumantyo, "Microwave Remote Sensing
Research and Education at Center for Environmental
Remote Sensing, Chiba University," IEEE Geoscienceand Remote Sensing Society (GRSS) Newsletter, Issue#159, pp. 32-38, June 2011.
[2] J.T. Sri Sumantyo, Chapter 11. Circularly Polarized
Synthetic Aperture Radar onboard Unmanned Aerial
Vehicle (CP-SAR UAV), Autonomous Control Systems
and Vehicles, Kenzo Nonami edn., Springer, December
2012.
[3] Yohandri, V. Wissan, I. Firmansyah, P. Rizki Akbar, J.T.
Sri Sumantyo, and H. Kuze, "Development of Circularly
Polarized Array Antenna for Synthetic Aperture Radar
Sensor Installed on UAV," Progress in Electromagnetics
Research C, Vol. 19, pp. 119-133, January 2011.

Scope of Asian Micro-satellite Consortium with Super-constellation
1

Yukihiro Takahashi1Space Mission Center and Department of Cosmosience, Hokkaodo University

ABSTRACTMicro-satellite with weight of 50-100 kg or less has unique characteristics and various merits
compared to existing large, middle and, even small (~200-300 kg) satellites. With advanced sensors,
the micro-satellites could play important roles as an operational tool in many applications including
climate studies and disaster management in the very near future. Here we would propose and discuss
the establishment of international organization, "Asian micro-satellite consortium" (AMC), which
promotes and accelerates the micro-satellite development and the discussion of data utilization. In
AMC we will discuss the possibility of future projects, such as “super constellation” involving morethan tens of microsatellites and unmanned air vehicles (UAVs) under international collaboration. At

this moment, institutes/universities in about 10 countries in SE-Asia show strong interest inthat collaboration.
Keywords: Micro-satellite, UAV, consortium, constellation, Asia
Contact Author: Yukihiro Takahashi, professor, Hokkaido University, Kita 10-Nishi 8, Kita-ku,
Sapporo, Hokkaido 060-0810
Tel: +81-(0)11-706-3567, Fax: +81-(0)11-706-2760
e-mail: yukihiro@mail.sci.hokudai.ac.jp

Introduction
Remote-sensing with satellite is one of the most strongest way to monitor the earth without
doubt. However, large satellite is expensive and sometimes its development takes about 10 years or
more. Here we consider micro-satellite with weight of 50-100 kg or less, which has uniquecharacteristics and merits compared to existing large, middle and, even small (~200-300 kg) satellites.
With advanced sensors, the micro-satellites could play important roles in various applications
including climate studies, disaster management, smart agriculture and fisheries in the very near future.
Hokkaido University has been developing micro-satellite technologies and promoting data utilization
involving experts in wide-ranging research fields together with Tohoku University and otherinstitutes/universities. We introduce advantages of micro-satellite with advanced sensors and discuss
the future applications, considering the combination with ground observing facilities.
Advantages of Micro-satellite
Advantages of 50-100kg class micro-satellite would be a key for future space development
dedicated to climate studies, disaster management, and smart agriculture and fisheries. Itscharacteristics and merits compared to middle and large sized satellite are: 1) low cost fabricationcompared to middle or large sized satellite, namely, 2-4 M USD for BUS and 1-2 M USD for mission
payloads. The launch cost will be about 2-3 M USD as piggyback and 5-6 M USD as scheduled
launch, 2) quick fabrication: about one or two years for flight model would be sufficient, enabling
application of the latest technologies, that could be even better than existing equipments onboard large
satellites, 3) on-demand operation in order to obtain detail information at a point of interest, and 4) the
low cost and quick fabrication make us possible to launch not a small number of satellites and operatethem as a network, which is called as constellation flight. In order to make the utilization of
micro-satellite, the highly-functionable advanced optical and radio-wave sensors are essential,
especially in conducting spectral imaging and radar measurement. On the other hand, UAV(uninhabited airborne vehicle) has a great potential in measuring local area with higher spatial
resolution than satellite with lower cost as well as “test bed” of spacecraft equipment in developing

phase. The important thing is to find the “best mix” among micro-satellite, larger satellite, UAV andground equipment.
Advanced Sensor development for Micro-satellite
Hyperspectral data will be one of the main players in optical remote-sensing from space in the
future, though there exist only few large satellites which carry hyperspectral imager at this moment.
For example, if we want to classify tree species or to estimate growth rate of trees or grasses in order
to conduct effective carbon management related to REDD+, the 3 color (RGB) imaging is absolutely
insufficient. However, at this moment, the very limited satellites carry hyperspectral sensor using
grating device, which is generally heavy, large and expensive compared to multicolor camera withfilters and its typical spatial resolution is only 30 m/s. Hokkaido University has been developing a
super multicolor camera using LCTF (Liquid Crystal Tunable Filter) technology. We can select any
colors with bandwidth of about 20 nm (5 nm in the future) in the range of 420-700 nm or 650-1050 nm
at 1 nm step, just controlling voltage for liquid crystal. This kind of LCTF camera is the only
instrument that satisfies both precise spectral measurement and high-spatial resolution up to 5 m (2.5m in the future) GSD.
Hokkaido University also has been developing thermal infrared camera using “commercial
grade” micro bolometer array technology, which is very useful to measure the surface temperature ofocean, ground and cloud. Especially this camera may play an important role in detecting forest fire in
the future. The costs of those micro-satellite sensors are 1/10 or less than normal IR sensors used inspace missions. But their absolute temperature and resolution are about +/- 3 K and +/-0.1 K,
respectively, which are good enough for various purposes.
All those advanced sensors are small and light, and require less power consumption, which arevery well match to micro-satellite or UAV. The first LCTF camera will be onboard RISING-2
launched in May 2014 and RISESAT planned to be launched in a couple of years.
Also Hokkaido University is promoting the development of active sensors collaborating withother university and institute. We are very much positive to realize the SAR micro-satellite with Chiba
University. On the other hand, LIDAR would be another key technology which could provide
information not only on the surface structure of forest, land or cloud, but also on the spectral data withvery narrow bandwidth of wavelength. We should consider all these passive and active methodologies
in order to maximize the output of micro-satellite.
Potential of Micro-satellite Constellation
The constellation realizes a frequent monitoring from the low earth orbit. If we inserted 48
satellites into proper orbits, we can watch any location in the world about every 7.5 min. Since thetime duration of one satellite passage over a certain place is 10-15 min, the 7.5 min interval means
actually continuous monitoring. Here we suggest the establishment of such “super constellation” withmicro-satellites (Figure 1). Though it’s not easy to launch and operate more than several tens ofsatellites by single country, if several or 10 countries establish a consortium and each country launches
5 or 10 micro-satellites, the total number could be easily over 50. On the other hand, each owningcountries would like to operate satellites for their own purposes. One solution might be that the acertain percentage of machine time of the satellite, for example, 80 percent, is used for their own
purposes, but 20 percent should be remained for international public use, such as serious disastermonitoring or periodic survey dedicated to such as climate study planned by international committee.
In order to construct the effective and practicable constellation, the key would be standardized
remote-sensing payloads with optimized satellite BUS and establishment of the new methodology forground network for micro-satellites tracking. Further, combining larger satellites designed for heavy orlarge payloads such as SAR with higher resolution or hyperspectral sensor, this micro-satellite
constellation would be a part of this comprehensive collaboration (Figure 2).

Figure 1. Schematic drawing of super constellation with 48 micro-satellites

Figure 2. Concept of satellite coordination for earth observation
Suggestion of Asia Micro-satellite Consortium
We would propose and discuss here the establishment of international organization, "Asian
micro-satellite consortium" (AMC), which promotes and accelerates the micro-satellite development
and the discussion of data utilization. Note that having the on-going micro-satellite project is not anecessary condition to join this consortium. AMC will consist of a domestic working group in eachcountry. The each working group is composed of 3 parts: BUS development team, payload

development team and data user team, involving various field scientists or engineers, such as forestry,
agriculture, fishery, flood, meteorology, climate, ionospheric/magnetospheric science, etc. The
schematic concept is shown in Figure 3. Also in AMC we will discuss the possibility of future projects,
such as “super constellation” consisting of more than tens of microsatellites and unmanned air vehicles(UAVs) under international collaboration. Examples of the basic functions of AMC might be 1)
information exchange not only in hardware development but also in data utilization methodologies
such as estimation of carbon fixation for RED++, identification of the best fishing place, the firstdetection of forest fire, 2) international people-to-people exchange, 3) capacity building, 4) organizing
workshops and TV conferences, 5) discussion of future missions including super constellation. At thismoment, we are contacting and encouraging institutes/universities in more than seven countries in
SE-Asia to be the founding member of AMC. Most of the institutes are interested in and/or basicallyagreed to the concept of AMC and we would like to establish AMC formally in this conference or
focus meeting in the near future.

Figure 3. Concept of Asian Micro-satellite Consortium (AMC)
Acknowledgment
Microsatellite project is supported by Hodoyoshi project promoted by Cabinet Office, and by
micro-satellite development projects promoted by MEXT, and Grants-in-Aid for Scientific Research(Kakenhi) No. 19002002, No. 24253002 and No. 255550005

Observations of ionosphere with Mini/Microsatellites- problems and solutionsKoichiro Oyama
Plasma and Space Science Center, National Cheng Kung University, Tainan 70101,
TaiwanCenter for Space Weather Study and Education, Kyushu University, Fukuoka, Japan________________________________________________________________________________
Abstract
Two problems which rise in ionosphere measurements by using DC Langmuir probe
onboard Mini/micro satellite are discussed. The first problem is related to the ratio of
the conductive area of satellite surface to that of the electrode which is used for the DC
Langmuir probe measurement.
Insufficient surface area ratio causes the satellite potential to further negative whenthe electrode is biased to positive. This means that the potential of the electrode is
reduced with respect to the ambient plasma. This makes the Ne measurement fromelectron current region impossible. Measurement of Te becomes less reliable, because
exponetial potion to calculate reduces. The second issue is related to contamination
layer which cover both satellite surface and electrode surface. Te which is measured bycontaminated electrode is, without exception, estimated higher than the true value.
Although contamination effects are removed by sweeping the electrode potential so fast,
generally, the measurement becomes difficult because frequency response of theamplifier system does not have enough frequency bands.
Keywords Ionosphere, microsatellite , measurements, contamination_________________________________________________________________________________
1.Introduction
DC Langmuir probe ( Langmuir andMotto-Smith,1924) is one of the key
in-situ instruments to study ionosphere.
It needs a counter electrode whose
conductive surface area is at least 1000
times larger than that of surface area ofthe electrode.
This requirement is usually fulfilled forlarge satellites which have been launchedso far for ionosphere study. Now we are
jumping into an era to use tiny satellites.
Although a tiny satellite does notaccommodate many scientific payloads, todistribute many tiny satellites in space
Contact author: Koh_ichiro Oyama, visiting
professor, Plasma and Space Science Center,
National Cheng Kung University, Tainan 70101,
Taiwan,E mail oyama@pssc ncku.edu.tw,
Mobile Phone +81(0)9060091193(the constellation) has a tremendous
potential to further advance theionosphere study.
However we willencounter serious problems when we use
conventional DC Langmuir probe tomeasure ionosphere parameter.
One of the problems is related to a small
ratio of conductive surfaces of counterelectrode to that of the electrode.
Conductive surface area of the satellite
for DC Langmuir probe should be morethan 1000 times to get electron densityfrom the probe current at space potential.
Surface area of the tiny satellite is muchsmaller, or even equal to the surface areaof electrode. As a result, measurement ofelectron density which uses electron
saturation bias range becomes difficult,because the potential of the electrodewith respect to the satellite (counterelectrode) cannot reach ambient plasmapotential. For the worst case, themaximum electron current is limited byion current. Accordingly an electronics
needs to measure low current flowing
through the electrode. Low ion current
very often is comparable to secondary
electron current from the electrodesurface.
The second serious problem isassociatedwithcontaminationofelectrode as well as satellite surface.
When the triangular wave is applied to aprobe, current/voltage characteristic (I-V)
curve shows different curve depending on
the increasing and decreasing bias, whichis called “hysteresis”. The hysteresis iscaused by the contamination on theelectrodesurfaceaswell
ascontamination of the satellite surface. To
avoid the hysteresis, frequency of thetriangular wave which is usually usedshould be increased up to 10Hz.
These two factors make it impossible touse DC Langmuir probe as an instrumentof tiny satellite. We review problems
which appear for the ionospheremeasurement by using tiny satellites,and propose ways avoid the problems toaccomplish accurate measurements.
2.Laboratory Experiments
2.1 Effect of surface area
So far we assumed that the conductive
surface area of counter electrode (satellite) ismuch larger than that of an electrode. In caseof tiny satellite, conductive area is notenough to apply DC Langmuir probe theory
which assumes infinite counter electrode.
The positive voltage which is supposed to be
applied to a DC Langmuir probe reduces,because the potential of the satellite is
automatically shifted to more negative withrespect to ambient plasma. As a result, to
get accurate Ne from the I-V curve becomesdifficult, although we can use the ion current
to get Ne roughly.
In order to see the effect of conductive
area, one cube which is supposed to be apicosatellite (Dimension: 24cm x24cmcx
20cm) is installed in a Space Plasma
Operation Chamber (SPOC). Electron
density (Ne) and electron temperature(Te) in the SPOC are 103-105 els/cm3, and1000-3000K respectively, depending on

the working voltage of plasma generator.
Plasma which is almost similar to F
region ionosphere plasma is produced by
Back -Diffusion type plasma source( Hui-Kuan et al., 2014).
3 conductive panels of different surfacearea（S1:75.08 cm2 ,S2:80.0 cm2,and S3:
80.09cm2） are placed on the satellite walls.
By connecting these three panels, we change
the ratios of surface area of cylinder electrodeand conductive planes as 2.83, 5.82, and19.4 . The floating potential of the satellite ,and the voltage which is applied to theelectrodes with respect to the satellite aremeasured with respect to the SPOC ground.
A cylindrical electrode ( 3mm in diameter,and 20 cm in length) is attached in order touse for DC Langmuir probe measurement .
The voltage which was applied to theelectrode with respect to the satellite waschanged from 0-3 V, and then from 3 to 0 V
in one second as a pink colored triangularwave shows in Fig.1a . The voltage of theelectrode (for example, for the area ratio of
2.83; green line) with respect to the chamber
ground varies from about 1.1 Volts to about 2
Volts almost linearly until first 0.2sec, andthen the voltage increase slows down. This
statement is also true for other surface area
ratios. We measured floating potential of
the satellite with respect to the SPOC ground.
The potential keeps almost constant value
until 0.2 sec, and starts dropping to -0.25V
for the surface area ratio of 2.83 (green
color) . Other two cases show almost thesame feature.
The behavior of electrode potential changes
with the frequenncy of the seep voltage, andshows a different value between increasing anddecreasing potential (hysteresis) due to thecontamination of satelliet surface. Detail
discusson will be made in a separate paper in
the near future.

2.2 Contamination of satellite surface
As mentioned above, contamination of
the satellite surface as well as of theelectrode becomes serious for DC probe
measurement. The current makes aclosed circuit, starting from electrode,contamination layer of the electrode(parallel combination of Rpc and Cpc),
sheath impedance of the probe (parallelconnection of Pps and Cps), plasma
impedance (parallel connection of Lp
and Cp), sheath around the satellite(parallel connection of Rss and Css),contamination layer of the satellite(parallel connection of Rsc and Csc), thenfinally to the satellite frame.
When conductive area of satellite is large
enough compared with the surface area ofelectrode, Csc >>Cpc, and Rsc <<Rpc. As Csc ismuch larger than Cpc, the satellite potential
does not change during the voltage sweep of
DC Langmuir probe , and therefore the effectof contamination layer of satellite is
negligible. However, when conductive
surface of the satellite (Asa) becomes nearly
the same as that of the electrode (Apr), I-V
curve is influenced both by electrodecontamination , the contamination of satellite
wall, electrode sheath resistance, and satellite
sheath resistance.
3.
Countermoves
foraccuratemeasurements
To measure electron temperature, Teand electron density accurately, Electron
temperature probe (ETP), and impedanceprobe(Gyro Plasma Probe) are available.
These two probes were developed by
Japanese scientists (Oyama and Chen,
2013). ETP applies small sine wave
signal to the electrode to detect thefloating potential shift which is caused asa result of the sine wave application. Te iscalculated from the floating potential
shift. Gyro plasma probe applies thesweep frequency signal from about 500
Khz to 10 Mhz (Wakabayashi et al., 2013).
As plasma impedance is a function of
frequency of the signal applied. Usually
one peak (sheath resonance) and one
minimum (Upper hybrid resonance)
appears in the output signal. Electron
density is obtained from the upper hybrid
resonance.
These two instruments are notinfluenced by electrode contamination as
well as satellite contamination. One more
instrument
which
can
now
be
accommodated is TeNeP. The TeNeP is a
modified version of ETP. Instead of a
fixed frequency oscillator of ETP, TeNeP
uses a circuit which changes thefrequency from 500 Khz to 10 Mhz.

TeNeP is compact with low power
consumption, and low data bit rate, lowcost but still provides an excellent
information. TeNeP was especiallyinvented for tiny satellite mission. The
TeNep can be accommodated in tiny
many satellites, which will be planned forthe study of ionosphere modified before
large earthquake.
Acknowledgements
The manuscript was prepared byusing materials which were obtained bythree master course students (C. S. Jiang,
Y. W. Hsu, and W. H. Chen) at National
Cheng Kung University. The author
would like to express Professor T.
Yosaphat of Chiba University, Japan forproviding a chance to participate in the
2nd Asia Future Conference (AFC),
sponsored by Sekiguchi Global Research
Association.
References
Fang Hui-Kuan, K.-I. Oyama, 2014, in
preparation
Langmuir, I., and H. Motto-Smith(1924), General Electric Rev., 28,
449-548, 616-623, 762-771, 810-820.
Oyama, K -I., and C. Z. Cheng, 91-106,
An introduction to Space
Instrumentation, Terra, Pub., edited by
Oyama and Cheng, 2013. ISBN No.:
978-4-88704-160-8
Wakabayashi, M., T. Suzuki, J. Uemoto, A.
Kumamoto, and T. Ono (2013), 107-124, An
introduction to Space Instrumentation, edited
by Oyama and Cheng.

Development of Space-based Magnetic Activities Measurement Mission in LAPAN’s
Micro-Satellites
Robertus Heru Triharjanto1, Harry Bangkit2,M. Arif Saifudin1
1)

Researcher, Center for Satellite Technology, National Institute of Aeronautics & Space (LAPAN)
2)
Researcher, Center for Space Science, National Institute of Aeronautics & Space (LAPAN)___________________________________________________________________________
Abstract
LAPAN has been observing space weather data using ground-based sensor, among others
magnetometer. With the develoment of micro-satellite technology in LAPAN, it become possible for
LAPAN to have space-based magnetometer. The paper elaborate the mission concept of the payload,
and the development progress that has been done to achieve the mission objectives. The learning
process done on the satellite-based magnetometer data handling at the Center of Satellite Technology
and Center for Space Science was started with the data handling of magnetometer in attitude control
system of LAPAN-A2 micro-satellite. With such knowledge, the specification and the test proceduresof magnetometer that will be on-board of LAPAN-A3 and LAPAN-A4 micro-satellite was defined.
The paper also discuss further planning that was drawn for the development of more scientific classgeomagnetic measurement mission in LAPAN-A4 micro-satellite.
Keywords : micro-satellite, science mission, geomagnet___________________________________________________________________________
1. Introduction
Space weather is the condition in thesun, solar wind, magnetosfer, ionosfer andthermosfer, may influence the capacity ofspace-based
technology,suchas
telecomunication and navigation satellites. Sun
phenomenon that may effect space weather themost are flare, coronal mass ejection (CME),
and coronal holes (CH). One of their effect ismagnetic storm. Magnetic storm occur whenparticles from Sun the came toward the Earthand meet its magnetosfer. Here, the indicationof the storm may be read from the change in
geomagnet data.

Contact Author: Robertus Heru Triharjanto,
Researcher, Center for Satellite Technology,
LAPAN, jl. Cagak Satelit no.8, Bogor 16310,
Indonesia
Tel: +6218317970546
e-mail: rtriharjanto@yahoo.com

Fig 1. Solar wind interaction with Earthmagnetic field [ref 1]
1.1. Geomagnet research at Center for Space
Science LAPAN
The geomagnet data observation can bedone using ground-based and space-based
sensor. In Indonesia at the moment, there are 11
sensorlocations,thatuse
fluxgate
magnetometer and magdas, which belongs toCenter for Space Science, National Institute of
Aeronautics and Space (LAPAN). The sensors
are also used in international collaboration
research, among other, between LAPAN and
SERC (Space Environment Research Center),
Kyushu University [Ref 2]

Fig 2. Geomagnet sensor location in Indonesia, and their international network [ref 2]
1.2. Microsatellite development at Center for
Satellite Technology LAPAN
The development of micro-satellite atCenter for Satellite Technology of LAPAN has
made it possible for LAPAN to have spacebased sensors. The microsatellite program wasstarted with LAPAN-A1/TUBSAT. The project
received funding aproval in 2003, where thesatellite development was done in Berlin,
Germany, and launched in 2007 as auxilary
payload on Indian PSLV-C7 rocket [refHardhienata]. Its 2nd and 3rd satellite, LAPANA2/ORARI and LAPAN-A3/IPB received theirapproval from in 2008, which the satellite
development is to be done in Bogor, Indonesia.
With the establishment of microsatellite
integration and test facilities in Indonesia (Fig
3A) and the completion of LAPAN-A2
integration in 2012, the planning was drafted
for further satellite tecnology development inIndonesia as illustrated in Fig 3B [ref 3].

For mission realiability, subsystemtechnology heritage is implemented in thedevelopment plan, i.e. LAPAN-A2 will cary thesame analog video camera payload as LAPANA1, in addition to a newly developed of digital
camera payload that has better resolution andswath. LAPAN-A2 will also cary space-borne
ship monitoring system (AIS) and employ
better automation in satellite attitude control[ref Triharjanto, 2012].
LAPAN-A3 will carry the same digital
camera payload as LAPAN-A2, and newly
developed 4-band multispectral imager payload.
The major improvement in the satellite is its
data transmition system, which are 16 times
faster than its predecesor [ref Hasbi, 2013].
In LAPAN-A4, in addition to the 2nd
flight of multispectral imager, the satellite will
cary thermal camera based on coolinglessbolometer technology, and a scientificmagnetometer payload from Center for Space
Sience of LAPAN.

Fig 3. (A) LAPAN’s microsatellite integration facility (B) LAPAN’s microsatellite roadmap

2. The Magnetometer Payload Definition
Center for Space Science and Center
for Satellite Technology so far has studied 2
scientificmicrosatellites
that
carry
magnetometer payload, i.e. Australian Fedsat,
and Brazilian SACI-1. Fedsat is a 58 kg,
50x50x50 cm microsatellite dedicated forseveral scientific missions, while SACI-1 is a
60 kg, 57x44x44 cm microsatellite also
dedicated for several scientific missions.

Fig 4. Fedsat & SACI-1 [refhttp://space.skyrocket.de/]
The geomagnet mission of Fedsat is tocontribute to the monitoring and mapping of thegeomagnetic field in the Australian region. The
satellite payload is high precision triaxial
fluxgate magnetometer with a reading range of+ 65.000 nT. Since the satellite orbit altitude isat about 800 km, the magnetometer needs to besensitive enough to measure the magnetic
perturbations of the order of 10 nT. In such
orbit, to measure field-aligned current
structures, the payload has a sample rate of 10
vector samples per second (vs/s) so that 1 km
structures can be identified.
Fedsat magnetometer is built by
Institute of Geophysics and Planetary Physics,
UCLA, which already has space heritage. The
sensor dimension is 11,4 x 5,4 x 6,1 cm, withmass of 1,62 kg (sensor 420 g, electronics 1,2kg), and power consumption of 3,5 W. To
ensure magnetic cleanliness from othersatellite’s subsystems, the sensor was placed on
2,5 m boom, which also serve to give gravity

gradient stabilization for the satellite. [refFraser]
SACI-1 magnetic sensor, which is also
from UCLA, is mounted at the tip of one of thefour solar panel arms. Therefore, the sensor is
50 cm away from the main body of the satellite
for the reason of magnetic cleanliness. The
sensor assembly is covered with a thermal
blanket in order to protect the sensors fromlarge temperature variations. The magnetometeris capable of measuring geomagnetic field
intensity in the range of + 65.000 nT withreading resolution of ± 1 nT. In SACI-1, themagnetometer data will be sampled at 10
samples per second. [ref Trivedi]
From the data of the two satellites it is
known
that
micro-satellites
thathasmagnetometer mission employ space-provensensor with reading range of + 60.000 nT, andthe reading resolution no less 10 nT, in which,such specification will become the base of
LAPAN’s magnetometer payload design.
Off-the-shelf option for magnetometer
payload with above specification are the spaceproven German magnetometer of Magson andspace-proven US made magnetometerof
TFM65. Magson magnetometer has weight of
280 g, and dimension of 3,5 x 5 x 5 cm, reading
acuracy 100 pT and reading range of +60.000
nT. Its power consumption is about 1 W.
TFM65 magnetometer payload has weight of
117 g, dimension of 3,5 x 3,2 x 8,2 cm, reading
range of +60.000 nT, and reading resolution of
35 pT. [ref 9]
3. LAPAN Satellite’s Magnetic NoiseIn LAPAN-A2, the magnetometer usedin its attitude control system (ACS) is fluxgate
VMFS-51, wich has reading resolution of 200
nT. Such magnetometer is designed fornavigation purposes of satellite and not meanfor scientific measurement. However, since thesensor has been integrated in the satellite, it canbe used to learn about the magnetic noise
LAPAN’s satellite platform generate and about
the sensor’s data handling system.
The study about the satellite magnetic
noise was done by the Center for Space
Science, by reading the emision from LAPANA2
satelliteusing
its
ground-basedmagnetometer, a Magson type. The reading
range of the sensor is +60.000 nT and its
accuracy is 10 pT. The experiment set-up is
shown in Fig 4, where the magnetometer isplaced at about 20 cm from the satellite body.
The magnetic noise emited by the satellite
during its operation mode is then read.

Fig 5. Satellite’s magnetic noise test set up [ref 8]
The study shows that LAPAN’ssatellite AIT facilities in Rancabungur, Bogor,
is not suitable to calibrate scientific classmagnetometer. The personel activities, which
may cary electromagnetic devices, as well asother devices arround the laboratory (including
car park nearby) disturb the reading. The
differential magnetic field reading shows thatthe magnetic noise from satellite subsystem isless than the noise coming from theenvironment. Therefore, the reading is repeatedat LAPAN facilities at Pameungpeuk, Garut.
Knowing that the magnetic feld from the air
coil can be predicted, and therefore can be
filetered in the reading software, the test thefocus on the magnetic noise that come fromreaction wheels. The test in Pameungpeuk use
the engineering model of the satellite that
contain the flight model reaction wheels(platform wheel in Fig 5).
4. LAPAN-A3 and LAPAN-A4
Magnetometer Configuration
The magnetometer chosen to be usedin
LAPAN-A3
isHybridFluxgate
Magnetometer (HFGM) type, which are arecommonly used for scientific space mission.
The HFGM is using a vector compensatedringcore sensor and the electronics for thedigital signal processing. The soft-magnetic
material of the ringcores is driven into
saturation by an AC excitation current. The
external magnetic field distorts the symmetry of
the magnetic flux in the core, which generates asignal at even harmonics of the excitation
frequency. Sensor and electronics are designed
for the selective measurement of the second
harmonics of the excitation frequency. A
feedback current is generated to compensate theexternal field at the ringcore position by aHelmholtz coil system. The component valuesof the external field are calculated by thesettings of field proportional feedback current
and the remaining field at the core position. [ref9]In LAPAN-A3, the magnetometer will
be used for attitude control system. However,since investigation is to be done to prepare thededicated scientific mission in LAPAN-A4.
Therefore,highaccuracy
fluxgate
magnetometer will be used. To minimize
magnetic noise from other the satellite
components, the sensor will be placed outside
the satellite body (Fig 6). In LAPAN-A4, its isplanned that the sensor is placed on deployable
boom at length of more than 1 m from thesatellite body.

magnetometer

Figure 6. LAPAN-A4 and LAPAN-A3 showing their posible magnetometer position
The magnetometer of LAPAN-A3 will
be operated continuously and take data withsampling rate of 1 Hz. A 2,4 Mb memory spaceis reserved on the satellite main computer forthe magnetometer data, which will be
downloaded via TTC link over Spitzberg andIndonesia. The reding will be synchronizedwith the satellite’s clock so that the location of
the reading can be identified.
For the calibration of the sensor, theCenter for Space Science is currently procuring
Triaxial Helmholtz Coil with dimension of noless than 1 x 1 x 1 m. The coils will be used tocallibrate all the center’s magnetic sensors, andto performed functional and calibration test on
LAPAN-A4’s magnetometer payload.
Kalibrator magnetometer merupakan
suatu sistem peralatan yang digunakan untuk
mengkalibrasi peralatan pengamat geomagnet(magnetometer). Magnetometer lama ataupun
yang baru dibangun perlu dikalibrasi untuk
mengetahui/menjaga akurasinya. Kalibrator ini
mengukur sekaligus tiga komponen magnet (sumbu X komponen horizontal Utara-Selatan,
sumbu Y komponen horizontal Timur-Baratdan sumbu Z komponen Vertikal).
5. Summary and Further Plan
Thedevelopment
progressofgeomagnet measurement mission in LAPAN’s
micro-satellites is :1. Has finished defining specification for
scientific class magnetometer payload

2. Has performed study on the magnetic
noise emmited by LAPAN’s microsatellite components
3. Based on the study, has made preliminary
design on the payload placement, andpayload operation scenario
4. Has prepared scenario on the payload
functional test, as subsystem and system,
as well its necesary facilities
Further research to be done is the study
the effect of boom on the attitude control ofsatellite. The study is important since the otherpayload of LAPAN-A4 is an imager, which
require good attitude stability.
6. Acknowledgement
Authors wish to thank Director of Center
for Satellite Technology, Mr. Suhermanto;
Director of Center for Space Science, Ms. Clara
Yatini; and Head of Geomagnet & Space
Magnetism, Center for Space Science, Mr.
Anwar Santoso; for facilitating this research.
7. References
1) http://en.wikipedia.org/wiki/Geomagnetic_s
torm (Jan 2014)2) http://www.serc.kyushuu.ac.jp/news/MAGSessRes2010/talk/20Setyanto-Real Time MAG in Indonesia.pdf(Dec 2013)3) http://www.lapanrb.org (Oct 2013)4) S. Hardhienata; M. Kartasasmita (2007)
The Strategy of Indonesian Satellite
Technology Development; Chp. 1 of
LAPAN-TUBSAT : From Concept to Early

Operation; Lembaga Penerbangan dan
Antariksa Nasional
5) B. J. Fraser, C. T. Russell, J. D. Means, F.
W. Menk, C. L. Waters (2001) FEDSAT An Australian Research Microsatellite;
Workshop on Applications of Radio
Science6) http://wwwssc.igpp.ucla.edu/personnel/russell/papers/F
EDSAT/ (Dec 2013)7) https://directory.eoportal.org/web/eoportal/s
atellite-missions/f/fedsat (Dec 2013)8) A. Santoso (2013); Pegukuran Medan
Magnet di Sekitar Bus Satelit Dalam
Kegiatan Kajian Ilmiah Muatan Satelit
LAPAN-A2/ORARI; 2nd Internal Report
Center for Space Science
9) A. Santoso (2013); Kajian Muatan Ilmiah
Satelit LAPAN-A3/IPB Dan LAPAN-A4;
3rd Internal Report Center for Space Science10) Indian Space Research Organisation(ISRO) (2003) PSLV Auxilary Payload
Manual;11) R.H. Triharjanto; M. Mukhayadi (2012);
Optimasi Misi dan Modifikasi Desain
Satelit Mikro LAPAN-A2; PengembanganSatelit Mikro LAPAN : Sistem, Subsistem,
dan Misi Operasi; IPB Press
12) W.
Hasbi,
Suhermanto(2013);Development of LAPAN-A3/IPB SatelliteanExperimental
RemoteSensing
Microsatellite; Proceeding ACRS, Bali,
Indonesia13) N. B. Trivedi, C. T. Russell, M. J. F.
Barbosa, S. L. G. Dutra, N. R. Teixeira, J.
D. Means, J. A. Neri, (2000); Geomagnetic
Field Investigation On The Polar
Microsatellite
SACI-I;
CoordinatedMeasurementsofMagnetospheric
Processes, Adv. Space Res., 25 (7/8) 13151323.
14) http://magnetometer.com/wpcontent/uploads/TFM65-VQSFEBRUARY-2008-Spec-Sheet1.pdf

Title: A New Millimeter-wave GBSAR for Landslide Monitoring
Koo Voon-Chet1, Josaphat Tetuko Sri Sumantyo2, Lim Tien-Sze3, Chan Yee-Kit4, Habibah Lateh5
1

Professor, Center for Remote Sensing and Surveillance Technologies, Multimedia University, Malaysia
2
Professor, Center for Environmental Remote Sensing, Chiba University, Japan
3
Senior Lecturer, Multimedia University, Malaysia
4
Associate Professor, Multimedia University, Malaysia
5
Associate Professor, School of Distance Education, Universiti Sains Malaysia, Malaysia

Abstract
Every year, over one million people are exposed to weather-related landslide hazards around the World.
Due to the recent climate change, it is likely that the decrease of permafrost areas, changes in precipitation
patterns and increase of extreme weather events will influence the weather-related mass movement activities.
This paper reports the recent development of a ground-based synthetic aperture radar (GBSAR) for
continuous monitoring of landslide-prone areas in Malaysia. It is an ultra-wideband system operating at 17
GHz with spatial resolution of 0.3 m in range and 5.8 mrad in cross range. The system is mounted on a rail
which travels along a linear guide to achieve SAR imaging. The GBSAR has been installed at a test site toprovide timely information for landslide monitoring and early warning system. The paper discusses thedesign, development and field experiments using the new GBSAR system.
Keywords: Synthetic Aperture Radar, Interferometry, Landslides, Millimeter-wave, Environmental Monitoring

1. Introduction
Synthetic Aperture Radar (SAR) is an active sensor
which can achieve fine along track resolution bytaking the advantage of radar motion to synthesize alarge antenna aperture. Over the past few decades,
SAR has been widely used as an important andefficient tool for Earth remote sensing [1]-[3]. SAR istypically operated in microwave frequencies andcapable of providing high resolution two-dimensional
images independent from cloud coverage and weather
conditions. SAR interferometry is a powerful andwell-established technique for the determination of
object displacements with high precision and accuracy.
Examples of applications using interferometric SAR(InSAR) include detection and precise measurement of
surface topography, glacier movements, as well as
ground deformation and subsidence [4]-[5].
The feasibility and the effectiveness of space-borne
InSAR for monitoring ground displacements at a
global scale due to landslides have been welldemonstrated [6]-[7]. On the other hand, ground-based
InSAR has the advantage of providing continuous
Contact Author: Koo Voon Chet, Professor,
Multimedia University, Jalan Ayer Keroh Lama,
75450 Melaka, Malaysia
Tel: 606-2523060 Fax: 606-2523059
e-mail: vckoo@mmu.edu.mymonitoring of landslide-prone areas at relatively low
cost and simple setup. For small-scale features orchange detection, a higher frequency band at
millimeter wave region is preferred as it is moresensitive to surface roughness and small-scale
structures such as rocks and debris. Examples of
millimeter wave Ku-band (16 GHz LISA, 17.2 GHz
IBIS) and W-band (95 GHz) ground-based SAR(GBSAR) systems have also been reported in [8]-[10],which clearly shows the capabilities of InSAR in
detecting small-scale features at a regional scale.
This paper reports the design and development of a
Ku-band ground-based SAR (GBSAR) system fortimely landslide monitoring. The system is mounted ona linear rail that moves along an azimuth range of 1.5
m. The key idea is to compare the phase of two or
more complex InSAR images that have been acquired
at different times. When terrain displacements occur inthe time elapsed between two image acquisitions, thephase change due to the tiny path length difference ofthe radar wavelength can be accurately measured in
the order of millimetric accuracy. By continuously
measuring these displacements, timely information canbe extracted for landslide monitoring and early
warning system.

Table 1: Design Specifications
No.

Specifications

1.
2.

Operating
Frequency
Bandwidth

Design
Value
17.26
GHZ
500 MHz3.

Waveform

FMCW

4.

Polarization

single, HH

5.

Transmit
Power
Antenna
Aperture
Antenna Gain
3dB
beamwidth

1W

6.
7.
8.

9.

10.
11.
12.

13.
14.

Synthetic
LengthRange
Resolution
AzimuthResolution
Maximum
Sensing
Distance
Sigma naught
SNR

5 cm
16 dB
24.0°
(azimuth)
24.0°(elevation)
1.5 m

Remarks
Ku-Band, λ = 17.4mm
range resolution =30 cm
For short range
operation.
Dual antenna, H
transmit and H
receive
30 dBmPyramidal Horn
AntennaAzimuth range
illumination: ~420 m
at range distance1000 mFor easytransportation andinstallation

0.5 m
5.8 mrad2.9 m at 500 m, 5.8
m at 1000 m.

1500 m−20 dB> 10 dB

at 1000 m

Figure 1 shows the geometry of the GBSAR. At asensing distance of 1000 m, the azimuth illumination
is approximately 420 m. The GBSAR will move along
a high precision motorized linear rail at 10 mm perstep, which is equivalent to 150 sample points inazimuth direction. At each azimuth position, the radartransmits a FMCW signal at Ku-band with total
bandwidth of 500 MHz to yield the range resolution of
0.3 m. After SAR processing, the azimuth resolution is
5.8 m at 1000 m.

Sensing distance 1000 m

2. System-Level Specifications
Table 1 summarizes the technical specifications of
the GBSAR system. The proposed system operates at
17.26 GHz (Ku-band) with a bandwidth of 500 MHz.
Millimeter-waves are chosen to allow the monitoringof small-scale changes. The spatial resolution is 0.5 m
in range and 5.8 mrad in azimuth range. FMCW
configuration is chosen for short-range operation. The
millimetre-wave radar front-end and antennas aremounted on linear rail with 1.5 m in length.

1.5 m

Figure 1: The GBSAR Geometry
3. GBSAR System Design
Figure 2 shows the functional block diagram of the
GBSAR system. It consists of three major components,
namely (1) RF and antenna subsystem, (2) embedded
radar processing subsystem, and (3) high precisionlinear scanning platform.
3.1. RF and Antenna Subsystem
The RF front-end module is depicted in Figure 3.
The baseband FMCW waveform is generated by acustom-designed direct digital synthesizer (DDS). The
clock frequency to drive this generator is delivered by
a 10 MHz phase-locked oscillator. The FM frequency
is set at 156 Hz, and the sweep bandwidth is 500 MHz.
This signal is then upconverted to Ku-band (17 GHz),
amplified and sent out through a transmitting hornantenna. The transmit power is about 30 dBm. A
directional coupler is used to couple a small portion ofthis power to the RF receiver’s mixer. The transmitting
antenna is a miniature pyramidal horn with aperturesize of 5 cm. It has 14 dB gain and 24° beamwidth inboth azimuth and elevation planes. The antenna pattern
is shown in Figure 4.
The RF receiver has multiple stages of low noise
amplifiers (LNAs), to amplify the weak signal returns
from the receiving antenna. The amplified signals willthen be mixed with a reference transmit signal toproduce the in-phase (I) and the quadrature-phase (Q)intermediate frequency (IF) signals. The maximum IF
signals are approximately 1.5 MHz at 1500 m.

temporal change detection. The hardware prototype ofthe embedded radar processing module is shown in
Figure 6.

Embedded SAR Processor

Figure 2: Functional Block Diagram of the GBSAR

Real-time SAR Raw

Real-time SAR

Data Capturing

Processing

ADC Card

Solid State Hard disk drive

Figure 5: Embedded Radar Processing Module
	
  
	
  

	
  
Figure 6: Hardware Prototype of the Embedded
Processing Module

Figure 3: RF Front-end Module	
  3.3. High Precision Linear Scanning Platform
In order to achieve stable and linear movement at
fine resolution, a high precision linear scanningplatform has been developed. Figure 7 shows the
hardware prototype of the linear scanning platform. Its
working length is 1500 mm and its achievable step sizeis 1 mm. For every SAR acquisition, a total of 150
range samples will be captured at a spatial interval of
10 mm along azimuth direction.

Figure 4: Antenna Radiation Pattern

3.2. Embedded Radar Processing Subsystem
The functional block diagram of the embedded radar
processing subsystem is shown in Figure 5. The I and
the Q of the received IF signals will first be digitizedby a 100 MHz analog-to-digital converter (ADC) andstored onto the onboard solid-state hard disk (SSD).
Upon completion of every scan (150 steps), thereal-time SAR processing module will read in the raw
data and perform SAR processing using range-Doppler
algorithm. The generated SAR image will then be
stored and compared with the next-scan image to yield

Figure 7: Hardware Prototype of the Linear
Scanning Platform

4. Field Experiments and Results
Figure 8 shows the experimental setup during a fieldtest at Melaka, Malaysia. Trihedral corner reflectors
are placed on a slope to perform external calibration.

(a) GBSAR In Operation

within ± 5 mm.

Figure 9: Point Target Return(b) Test Site
Figure 8: Experimental Setup for GBSAR
For every SAR acquisition, the GBSAR travels
along its azimuth direction and collects a total of 150
range samples at every 10 mm interval. The echo of
one single target within the antenna beam will bepresent at every azimuth position and is therefore
defocused. After range compression, an ideal point
target appears at each pixel of the recorded raw image
with the same amplitude but the phase is a function of
the antenna position. Azimuth range compression isachieved by multiplying the azimuth range sample
with the complex conjugate of the baseband reference
signal at frequency domain, and finally, the resultant
signal is inverse-Fourier transformed to obtain afocused image in both range and azimuth domain.
A sample of the focused SAR image with single
point target is shown in Figure 9. The point target isthen shifted by 10 mm for every subsequent scan, for
10 scans. Figure 10 shows a sample of the phasedifference plot derived from two SAR images taken at
different time. The phase difference dφ is extracted tocompute the displacement dR by using the following
equation:dR=

λ dφ / 4π(1)where λ is the wavelength of the transmit frequency.
The measured displacement results are presented inTable 2. It is clearly shown that the GBSAR is capableof detecting sub-centimeter changes with error boundFigure 10: Temporal Change Detection using Two
SAR Images
Table 2: Displacement Measurement Results
Target Setup
Distance (mm)
10
20
30
40
50
60
70
80
90

MeasuredDistance (mm)
11.6
21.7
31.6
42.1
51.6
62.0
71.1
84.2
93.4

Error (mm)
1.6
1.7
1.6
2.1
1.6
2.0
1.1
4.2
3.4

5. Conclusions
A new ground-based Synthetic Aperture Radar
operating at 17 GHz has been designed and developed. It
has 0.3 m × 5.8 mrad spatial resolutions, and change
detection capabilities up to 5 mm. The system will be
used for landslide monitoring at selected test sites in
Malaysia.

6. References
1) Wiley, C. (1985) Synthetic Aperture Radars: A
Paradigm for Technology Evolution. IEEE
Transaction on Aerospace Electronic Systems, vol.
21, no. 3, pp. 440-443
2) Henderson, F. and Lewis, A. (1998) Manual of
Remote Sensing: Principles and Applications of
Imaging Radar. New York: Wiley.
3) Cumming, I. G. and Wong, F. H. (2005) Digital
Processing of Synthetic Aperture Radar Data:
Aglorithms and Implementation. Norwood, MA:
Artech House.
4) Rosen, P. A., Hensley, S., Joughin I. R., Li, F. K.,
Madsen, S. N., Rodriguez, E. and Goldstein, R. M.
(2000) Synthetic Aperture Radar Interferometry.
Proceedings of the IEEE, vol. 88, no. 3, pp.
333-382.
5) Massonnet, D., Rossi, M., Carmona, C., Adragna,
F., Peltzer, G., Feigl, K. and Rabaute, T. (1993)
The Displacement Field of the Landers Earthquake
Mapped by Radar Interferometry. Nature, vol. 364,
pp. 138-142.
6) Lanari, R., Mora, O., Manunta, M., Mallorqui, J. J.,
Berardino, P. and Sansosti, E. (2004) A Small
Baseline Approach for Investigating Deformations
on Full Resolution Differential SAR Interferograms.
IEEE Transaction on Geoscience and Remote
Sensing, vol. 42, no. 7, pp. 1377-1386.
7) Crosetto, M., Crippa, B. and Biescas, E. (2005)
Early Detection and In-depth Analysis ofDeformation Phenomena by Radar Interferometry.
Engineering Geology, vol. 79 (1), pp 81-91.
8) Tarchi, D., Casagli, N., Moretti, S., Leva, D. andSieber, A. J. (2003) Monitoring Landslide
Displacements by using Ground-based Radar
Interferometry: Application to the Ruinon
Landslide in the Italian Alps. Journal ofGeophysical Research, 108, pp. 10.1-10.4.
9) Rödelsperger, S., Läufer, G., Gerstenecker, C. andBecker, M. (2010) Monitoring of Displacementswith Ground-based Microwave Interferometry:
IBIS-S and IBIS-L. Journal of Applied Geodesy,4(1), pp. 41-54.
10) Helmut. E., Hagelen, M., Johannes, W. andSommer, R. (2008) High Resolution Millimeter
Wave Measurement Radars for Ground Based SAR
and ISAR Imaging. Radar Conference, pp. 1-5.
11) Suzuki, S. and Honda, T. (2012) Research on Low
Carbon Planning. Journal of Sekiguchi Global
Research Institute, pp. 77-82.

The challenge for still unresolved development of Multi-band Equatorially Orbiting POLSAR
satellite sensors - an integral task for the major space-SAR technology centers world-wide –focused on the Indonesian Islands Environment
Wolfgang-Martin Boerner
Professor Emeritus, University of Illinois at Chicago

Abstract
With the relentless increase in population density, the anthropogenic expansion into natural terrestrial
hazard zones has become irreversible resulting in ever more catastrophic disasters, not only in the
Asia-Pacific region more so within the entire tropical belts engulfing Mother Earth. Thus not only theIndonesian-Pacific Islands, so also South America, Africa and back via the Indian Ocean Islands toAsia-Pacific, these natural events like volcano eruptions, earthquakes with emerging tsunami, cyclones andsevere down pours have caused havoc, loss of lives, destruction of infrastructure and above all intentionalmanmade interference resulting in the deterioration of pristine tropical jungle forests. What is required isaround-the-clock local and wide-area surveillance and remote sensing of the vegetative cover for which firstwell designed optical equatorially orbiting satellite sensors had been developed but their successful
implementation failed because of the ever increasing cloud, precipitation, humidity and aerosol cover within
the entire equatorial belt of +/- 15* ~ 20* latitude rendering penetration at optical wavelength mostly
ineffective. Hence, we must take recourse to microwave sensing, and implement radar and synthetic aperture
sensors from air and space operational at day & night independent of weather; and the sensors especiallysuited are the fully polarimetric POL-SAR sensors developed for satellite remote sensing by the major SAR
technology development centers worldwide. As first and main test case, we will explore the IndonesianIsland region.
Keywords: equatorial satellite orbits; polsar imaging; Indonesian islands surveillance

Introduction
The outstanding performance capabilities of thethree Satellite POLSAR sensors are well established;
and in this exposition the exploitation of the fullypolarimetric
ALOS-PAL=PPL=SAR
mode
isdemonstrated by implementing the Niigata-University
four-scatterer SAR image decomposition withcoherency-matrix rotation proving the superior
imaging capabilities of the fully polarimetric SAR
modes not only for the ALOS-PALSAR L-Band andsimilarly to the S-Band, C-Band and X-Band. The
novel fully polarimetric POL-SAR image processing
techniques are then applied to natural hazard detection
and subsequent disaster reduction of taiphoons withland-slides, volcano eruptions with plume aftereffects& landslides, and of earthquakes with drop-slips
Dr. Wolfgang-Martin Boerner, Professor Emeritus, University
of Illinois at Chicago, Electrical and Computer Engineering,
Communications, Sensing & Navigation Laboratory,
900 W. Taylor St., SEL (607) W-4210, M/C 154
CHICAGO IL/USA-60607-7018
Tel: +[1] (312) 996-5480 Home: + [1] (847) 498-4457
e-mail: wmb1uic@yahoo.com

experienced within the SE-Asian/Pacific Ring-of-Fire
including next to Japan in Taiwan, the Philippines andIndonesia, promoting equatorially orbiting Single andTandem L-/S-/X-Band POLSAR sensor deployment.
Major emphasis is placed on the development ofequatorially orbiting satellite sensors between +/-12(15)* latitude.
The Indonesian Islands stretch over almost fourtime zones along the equatorial belt in between +/10* latitude, and its lush vegetation along with its
mineral resources are exposed to increasing natural
hazards like volcano eruptions, earthquakes andseaquakes with ensuing tsunami, cyclones withdevastating floods plus ruthless mineral mining andconversion of natural tropical jungles into oil-palm
estates for ethanol production. Thus, disaster
assessment and prevention has become an ever morepressing topic of top priority. Current ground-based
disaster damage assessment methods are cumbersome
and costly due to sudden sporadic hazard occurrences;and local point measurements are not representative oflarger affected regions. Due to the strong spatial andtemporal
dynamics
ofgeo/bio-environmental
constituents enhanced by strong local weather changes,
frequent continual observations are necessary forwhich microwave satellite remote sensing and stresschange monitoring provide the sought for repetitive
monitoring capability and synoptic coverage subject
to equatorially orbiting POL-SAR satellite
implementation.

decomposed with the launch of the three fullypolarimetric multi-modal SAR Satellites currently
only at L-, C-, X-Band and its first tandem
satellite-pair update of the DLR TanDEM-X. All ofthese efforts will be topped by near-future joint
DLR-JPL
DESDynI/Tandem-L
wide-swath,high-resolution
fullypolarimetricsensorimplementation, which in due time will be enlarged toaccommodate next to the L-, C-, X- also P-Band
sensors using one and the same reflector, thenenabling full assessment also of dense tropical forests
which will for example result in curtailing illegal
deforestation, there and elsewhere.

Fig.1. ALOSPALSAR, RADARSAT-2, TerraSAR-X.

Method of approach
The basic radar technologies to do the job are themultimodal Synthetic Aperture Radar (SAR) sensors.
In the meantime, fully polarimetric multi-modal highresolution SAR systems at multiple frequencies andincidence angles were introduced first with themulti-band AIRSAR of NASA-JPL culminating in theonce-only pair of SIR-C/X-SAR shuttle missions of1994 April and October as well as the SRTM shuttle
mission, which laid the ground work for true day/night
space remote sensing of the terrestrial barren andvegetated land and ocean covers using multi-bandpolarimetric SAR Thereafter, the Canadian CCRS,
the German DLR and the Japanese NASDA & CRL{now JAXA & NICT} took over introducing andsteadily advancing the Convair-580, the E-SAR (nowF-SAR) and Pi-SAR airborne highly advanced fullypolarimetric sensors platforms, respectively [1, 2].
These separate international multi-modal fullypolarimetric and also interferometric airborne SAR
developmental
efforts
culminatedinawell-coordinated group effort of these three
independent teams eventually launching and operating
Fully Polarimetric Satellite SAR Sensors (Fig. 1) at
L-Band (ALOS-PALSAR launched by JAXA/Japan in2006 January – and to be followed by
ALOS-PALSAR-2 &3); at C-Band (RADARSAT-2
launched by CSA-MDA in 2007 December – to befollowed by independent RADARSAT-3&4) and at
X-Band (TerraSAR-X launched by DLR-Astrium in2007 July with the follow-on tandem mission
TanDEM-X (Fig. 2) launched in June 2010). Thus,
international collaboration on advancing day/nightglobal monitoring of the terrestrial covers was

Fig.2. TanDEM-X Configurations.

Fig.3. Indonesian Islands within Equatorial Belt.

Satellite sensor implementation
The ALOS-PALSAR (L-band), the RADAR-SAT-II(C-Band) satellite POLSAR sensors together withTerraSAR-X and TanDEM-X satellite sensors
provided spectacular imagery at Indonesian sites
chosen at random, whereas in this proposed
equatorially orbiting satellite POLSAR sensors are theobjective to identifying minute surface changes due tonatural hazards and anthropogenic destruction of the
precious tropical vegetative ground covers within theequatorial belt of the Indonesian islands stretchingover almost four time zones along the equator along
which some 120 active volcanoes periodically erupt.
The disastrous destruction of the tropical environmentis inflicted mainly by coastal oil rigging, rigoroussurface mining (coal, ore, gold, precious and rareminerals), ethanol production by replacing virgin
tropical jungles by oil palm monoculture forests,
calling for the immediate implementation of the DLR
TerraSAR-X/TanDEM-X
as
well
as
ALOS-PALSAR-2 and RADAR-SAT-3 satellite
sensors.

Fig.4. Deforestation Map of Indonesia.

Fig.5. Equatorial Satellite Orbits over Indonesia.

Fig.6. Mineral resources map.

Selection of desired test sites
For demonstrating its applicability a selected set of
distinct test-regions spread along the entire equatorial
extent with its chain of some 120 active volcanoes
needs to be specified from North-west Sumatra via
Java, Nusa Tenggara, Kalimantan, Sulawesi to the

Maluku/Timor islands and Papua. During the recent
years, excellent satellite X-Band remote sensing
results had already been obtained for some randomly
selected regions over Kalimantan on Borneo [3],which needs to be supplemented by a more rigorous
selection of pertinent test sites across all of Indonesia
with the upgraded TerraSAR-X/TanDEM-X satellite
DLR sensors [3]. With the aid of Figures 2, 5 and 6,
here we propose a set of possible sites for further
selective consideration from West to East, requiring
the input of local specialists:
Table 1. Selection of desired test sites
SUMATRA
Banda Aceh
Medan
PadangBandar Lampung
Krakatao
JAVA
BantenJakarta/Depok
Bogor
Bandung
Yogyakarta
Solo/Surakart
Semarang
Surabaya
MalangJember
NUSA TENGGARA
Bali/Denpasar
Lombok/Mataram
Timor/Kapung
KALIMANTAN
Palembang
Banjarmasin
Palangkraya
PontianakSamarinda/Balikpapan
SULAWESI
Makassar
Kendari
Palu
MenadoMALUKU/PAPUA
Ambon
Biak
SorongMerauke/Iran-Jaya

Fig.7. Chain of Indonesian volcanoes.

Recommendations
At each of the many cited regions, distinct local sites
peculiar physical, climatologic and anthropogenic
conditions exist, and in order for covering all of thesediverse sites, it is indeed essential for not waiting any
longer but have a properly chosen set of equatoriallyorbiting multi-band sensors developed and test sites
concurrently monitored with other near field testing
methods of for example the local island agricultural,
forestry and aquacultural institutions plus mining
companies. In order for realizing this urgently
required design and development of equatoriallyorbiting with multi-band POLSAR satellite sensors
with sufficiently wide swath-width for covering theentire extent of the Indonesian islands across its
equatorial belt, all of the leading multi-band
POL-SAR design and development centers need to becalled for immediate action without national and/or
institutional ego but in view of its superior relevancefor the future health of Mother Earth.

Fig.8. Natural Hazard Distribution in Indonesia.

Development of equatorially orbiting multi-bandpolsar satellites
Although LAPN-TUB had initiated the successful
development of mini-satellites equipped with Opticalsensors for equatorial orbital monitoring over theequatorial belt at very narrow swath-width providing
12 ~ 16 daily local passages, no mission-dedicatedmicrowave sensor was hitherto developed for
geo/bio-environmental
remotesensing
andstress-change monitoring. However, considering thewide plethora of diverse applications a multi-bandwide-swath fixed equatorially orbiting satellite of theMulti-band DESDynI-Tandem configuration withbeam-shaping capability enabling ~ 400 km to 500 km
swath-width at L-, S-, and X-Bands ~ would ideallybe desired and should be aimed for to become
operational within 5 to 12 years. Not only Indonesia
but all tropical environments along entire terrestrial
equatorial belt require the urgent deployment of fullypolarimetric POL-SAR sensors including theintermittent tropical oceans within which major global
weather phenomena like cyclones develop.

Figure 9 Closed loop Equatorial Satellite Orbits

Conclusions
The challenge is thus to develop equatoriallyorbiting SAR, preferably POL-SAR satellite sensors,within the desirable P/L/S/C/X/Ka multi-bands, which
does pose severe technological problems due to thesteep incidence-angle illumination on one hand, andbecause of the fact that the major SAR Technology
Designers reside far outside the equatorial belt not
being excited about SAR sensor development for thetropical belt anywhere. Therefore, we need tomobilize and draw full responsible attention of themain SAR Development Centres worldwide such as
NASA/JPL, ESA/ESTEC, JAXA/EORC, CSA/SAR,
DLR/SAR, DSTO/SAR, ISRO/SAC, INPE/SERE plus

NTU-Temasek,NCU-CSRSR,LAPAN/RANCABUNG
UR, and so on; joining forces and strongly
contributing to a viable multi-band general bi-static(including cross/along)-track POLSAR sensor
technology, well suited for equatorial monitoring
within orbits of +/- 20* latitude. Once this urgent goalis achieved, local regions could be observed daily up
to 12 to 14 times, covering both the land and ocean
regions essential for environmental protection andmeteorological forecasting, respectively, on a hitherto
unprecedented global level. The Indonesian Islands
environment will be considered as a prime test case.
More importantly, it must be of top priority to
implicate the network of international radar
polarimetry community at the National (LIPI, BMKG,LAPAN) and envisioned Indonesian Geomatics &Remote Sensing Centers for influencing a plethora ofother local campus wide disciplines engaged inenvironmental and humanitarian for implanting thebenefits of SAR Polarimetry with a special emphasis
on monitoring and maintaining the environmental
health of our Mother Earth which is under severe
attack especially here in Indonesia!
Acknowledgment
The kind provision of figures and maps regarding
Equatorial Satellite Orbits by Drs. S. Hardhienata andRoberto Heru Triharjanto of LAPAN as well as theclose collaboration of several local IEEE AES/GRSS
experts is sincerely acknowledged. The excellent fullypolarimetric POL-SAR images contributed byProfessor Yoshio Yamaguchi and his team at Niigata
University deserve our highest attention. A special
note of sincere gratitude is extended to Dr.-Eng.
Josaphat Teteku Sri Sumantyo sensei of Chiba
University for inviting this presentation for
SOMIRES-2014 at Denpasar, Bali, Indonesia. Lastand not least, in addition the excellent contributions
for preparing this paper by GRA Eng. Tadahiro
Negishi are appreciated with highest respect.

References
1) Wolfgang-Martin Boerner, 2011, “International Collaboration on
advancing microwave radar remote sensing and stress-changemonitoring of the terrestrial covers from space for the benefit ofsustaining the biosphere in which we reside”, IEICE Global Plaza,
Website Community Plaza.
www.ieice.org/eng/global_plaza/index.html
2) A. Reigber, M. Jäger, J. Fischer, R. Horn, R. Scheiber, Prats, A.
Nottensteiner, Szstem Status and Calibration of the F-SAR
Air-borne SAR Instrument, Proc. IGARSS 2011, Vancouver, BC,2011 August, pp.1520 - 1523
3) Irena Hajnsek et al, INDREX II, Indonesian airborne

ESAR radar experiment campaign over tropical forests at
L/P-Band of Kalimantan, Nov 2004 (Technical Report)
4) Y. Yamaguchi, W.-M. Boerner, R. Sato, H. Yamada,
ALOS-PALSAR QUAD-POL Images, GRS Newsletter,
June 2009, pp. 9 – 12.
5) Gulab Singh, Y. Yamaguchi, W.-M. Boerner and S.-E. Park,“Monitoring of the March 11, 2011, Off-Tohoku 9.0
Earthquake with Super-Tsunami Disaster by implementing
fully polarimetric high resolution POLSAR techniques”
Proc. IEEE, vol. 101, no.3, pp.831-846, March 2013.
S;
Triharjanto,
R.H.
(Editors);
6) Hardhienata,
LAPAN-TUBSAT : From Concept to Early Operation;
Lembaga Penerbangan dan Antariksa Nasional; 2007 (alsosee LAPAN-A2 : Indonesian Near-Equatorial Surveillance
Satellite 18th Asia-Pacific Regional Space Agency Forum(APRSAF), Singapore, 2011)
WMB-SOMIRES14-Final=140226

The Plan for Space Observation Network Installation in Southeast Asian Region
Tu Hwan Kim1, Sung Ho Na2, Seung Yong Kang3
1Professor, Department of Space Electronics Information Engineering, Ajou University
2Research Associate, Department of Space Electronics Information Engineering, Ajou University
3Master student, Department of Space Electronics Information Engineering, Ajou University

Abstract
In the near future, after spread of the small SAR satellites in Southeast Asian region, each countries will installsmall ground stations to receive data from satellites. If the ground stations will be equipped with S/X bandreceiving system, they may be used as Geodetic VLBI (Very Long Baseline Interferometry) station. In otherwords, it is possible to do VLBI observation with main station which has a 20 m class antenna equipped withbroadband receiving system. And then it can be used for multiple purposes, such as resources exploration, crustal
deformation, monitoring of natural disasters and so on.
On the other hand, there is no geodetic VLBI observation networks in Southeast Asia, and they do not use theWorld Geodetic System (WGS), which is adopted worldwide. To use the WGS, one should determine accurately
the reference origin for his country, and then build its local reference coordinate system. For this purpose, after
installing the geodetic VLBI observation station, it is necessary to accurately determine the coordinates of theobservation station. In this way we can build the new national reference coordinate systems based on the WGS. To
perform the geodetic VLBI observation thereof, we can construct the international joint space observation networkwith small ground stations and the hub observing station with a 22m antenna of Korea.
This paper discuss the multi-purpose space observation network installation in Southeast Asian region.
Keywords: Small SAR Satellite, VLBI, Space Observation Network, WGS

1. Introduction
In 1995, Korea determined the origin point of its
new national geodetic system which conforms to theworld geodetic system by VLBI co-observation withJapan, and the baseline between two VLBI stations inboth countries were accurately defined (Figure 1). At
this time, the antenna diameter was 26 m (in Japan)
and other one was 3.8 m (in Korea). Each observation
took 24 hours, and it was repeated 4 times. Likewise,
the origin point of the new national geodetic systemthat conforms to the world geodetic system of each
Southeast Asian nation can be determined after 3-mclass antenna installations and co-observations with
Sejong VLBI center (in Korea). The 3-m class antenna
can be operated at the ground station for datatransmission from small SAR satellite as well.
Fig.1. Korea-Japan geodetic VLBI co-observation(1995)

Contact Author: Tu Hwan Kim, Professor, SpaceElectronics Information Engineering, Ajou
University, 206, World cup-ro, Yeongtong-gu,
Suwon-si, Gyeonggi-do 443-749, KOREA
Tel: 82-31-219-2648
e-mail: thkim@ajou.ac.kr

Table 1. The origin point of Korea reference frame(ITRF 94 EPOCH : 1995. 827)
X = - 3062002.5526 m
Y = 4055436.7504 m
Z = 3841860.8691 m
2. WGS and geodetic VLBI
Earth has very complex surface which is composedof mountains and seas, etc. In order to map
geographical characteristics, a spatial reference frame
is required. The spatial reference frame must be easy
to use and simple, and include clearly defined geodetic
control points and reference axes for accurate
positioning and intuitive association with the physicalworld.
Reference frame includes definitions for positioning,commentary coordinates, processing method withnecessary constants. SLR and geodetic VLBI havebeen used to determine International Terrestrial
Reference Frames. The origin points of national
geodetic system can be defined by geodetic VLBI in
Southeast Asia region.
The coordinate systems of Korea and Japan werecombined in mm-accuracy from geodetic VLBI
co-observation (in 1995). The Cartesian coordinates of
the Korean geodetic origin referenced to ITRF 94 areshown in Table 1. It was found that, the baseline
between Suwon and Tsukuba has been reduced by 40
mm per year.
VLBI observation is performed as follows. Morethan 2 antennas simultaneously receive the radio
waves coming from compact radio source (Quasar) in
the several billion light-years distance. Each station
has independent standard frequency of high stability.
Received signals are sampled at reference signal which
is supplied from standard frequency device. Result of
the correlation process for the digitized signal is
examined, and then the time difference of the same
wavefront to reach both antenna is accurately
calculated (time accuracy over 1 part per 10 billion).
Main component of this differential time is thegeometric delay 𝜏𝑔 (𝜏𝑔 = 𝐷 ∙ 𝑠/𝑐) which is determined

Fig.2. Geometric delay time 𝜏𝑔by the vector 𝐷 (direction to the radio source) and thevector 𝑠 (baseline between both antennas) (Figure 2).
Observation for geometric delay time is repeatedly
performed with different radio sources. After all, theearth direction from the radio source, the position of
the antenna on earth surface, the position of the radiosource on celestial sphere, all of these can be
determined by mm-accuracy (0.1 milliarcsecond inangle). The origin point of new national geodetic
system is to be determined accordingly.
3. Small SAR satellite development, manufactureand spread
The small satellite can be developed at low cost in ashort period of time while the large satellite
development will take a long period of time to researchand need a huge amount of investment. Therefore, thesmall satellite development has an advantage in thedevelopment of space technology. As shown in Figure
3, this small satellite development is included as partof the "Korea National Space Development Program
Roadmap" by detailed action plan. The proventechnology in the small satellite can be adapted to thelarge multi-purpose satellite in the future.
The multi-purpose satellite can be made in Korea by
the using the small satellite technologies. And Korea
government has a plan to launch a next generation
small satellite per 3-4 years. These technologies havebeen not studied in Korea before, micro satellite will
be priority developed among the plan for small
satellite of South Korea. Ajou University has made a
MOU with Prof. Josaphat Tetuko Sri Sumantyo in
National Chiba University, Japan who are excellent fordevelopment of the micro SAR satellite. The micro
SAR satellite is most popular as the utility of the microsatellite.
If the micro SAR satellite is developed by National
Space Program, Ajou University will develop thestandard satellite for micro satellite with corporations
and supply it to domestic and Southeast Asian
countries (if necessary, perform ODA). Then it will
help to accelerate the space industry. Especially, it
contributes to the advancement of science andeconomy of countries in Southeast Asia which haverich resources and many natural disasters.

Fig.3. Korea national space program (Satellites) roadmap
4. Southeast Asia space network installation
Countries in Southeast Asia have rich natural
resources but they have many natural disasters, too.
Thus these countries have needs of earth observations
with observing satellite and installing the small groundstation to gather and utilize the desired observing data
effectively. The space observation network can beutilized as the remote sensing exploration or theobservation of natural disasters. Moreover, it is thebenefits of the small ground station that the cost of a
installing is much cheaper than that of the large groundstation.
Meanwhile, in Southeast Asia, the geodetic VLBI
observation network is not existed (Figure 4) and theworld geodetic system is not used. However, in thesedays, most countries commonly use the world geodetic
system as a national geodetic system. To establish theworld geodetic system of a country, the origin point of
national geodetic system should be determined exactly.
For determining the origin point, the country should
install the geodetic VLBI observatory station and thendo the international VLBI observation. The measured
point becomes an origin point of the national geodetic
system, and the new coordinate system of the wholecountries are determined based on it. Finally, the newnational geodetic system is established based on theworld geodetic system.
For the geodetic VLBI observation, if the diameterof an antenna at one side is more than 20m, then 3m is
acceptable as a diameter of the other side antenna. If
the Space Geodetic Observation Center (in Sejong-si,
Korea) which has the 22m-diameter antenna play arole as the central station, then the geodetic VLBI
observation can be possible by using the small groundstation with the 3m-diameter antenna in Southeast Asia.
For that, only requirement is that the replacement of

the antenna receiver for the satellite communication
with for the geodetic VLBI receiver.
When the geodetic VLBI observation is possible,
each country can not only determine the origin point of
the new national geodetic system, but also measure thevariation of plate movements in Southeast Asia region.
5. Conclusions
According to the Korea national space program
roadmap, Ajou University and Chiba University willdevelop micro SAR satellite. It will be manufactured
by corporates and will be spread to Southeast Asia.
Micro SAR satellite will explore resources andmonitor natural disaster. It will be supported by groundstation which is designed to allow VLBI observation(Figure 5). The ground station can be origin point of
national reference frame according to WGS when
perform VLBI observation. In that case, Korea can be
the hub to support it, and these network will be
multi-purpose space network.

Fig.4. IVS Network Station (2013)

Fig.5. Southeast Asia space observation network (plan)
6. References
1) Tuhwan, Kim and Sasao, T. (2004) Research for thebasic planning and feasibility study of constructionof geodetic VLBI, pp. 14-192) Tuhwan, Kim and Jaehyun, Kim (2013) Micro
SAR Satellite Development in Korea and a Plan ofSpace Observation Network in Southeast Asia.
Proceeding of SOMIRES 2013, pp.32-33
3) Tuhwan, Kim (2001) Research for the introductionof geodetic VLBI, pp. 40-44
4) http://ivscc.gsfc.nasa.gov/stations/ns-map.html

Image Quality Comparison of Linearly Polarized and Circularly Polarized SAR
Heein Yang1, Bambang Setiadi2, Josaphat Tetuko Sri Sumantyo3, Jae-Hyun Kim4
1 Master student, Department of Electrical Engineering and Computer Science, Ajou University
2Ph. D candidate, Center for Environmental Remote Sensing, Chiba University
3Professor, Center for Environmental Remote Sensing, Chiba University
3Professor, Department of Electrical Engineering and Computer Science, Ajou University

Abstract
Synthetic Aperture Radar (SAR) is recognized as a powerful surveillance and land observation purpose systemthese days. An SAR sensor is usually loaded on moving platform such as aerial vehicle or satellite then acquires theimages of remote area in interest. Also this system uses microwave for its own illumination source, therefore it canbe operated regardless of the weather condition. When SAR system performs its mission in space, there areionosphere and air in the path of satellite and the target as a propagation medium. Conventional SAR system uses
linearly polarized (LP) microwave and as LP wave traverses through the ionosphere, Faraday rotation (FR) effectoccurs. FR makes the reference plane of microwave tilt slightly, consequently causes polarization mismatch when
receiving the backscattered signal. This polarization mismatch eventually degrades the image quality such as image
burling, degradation of contrast, and etc. To cover up the problems of conventional LP-SAR system, this paper
proposes that circularly polarized (CP) SAR system which can get rid of polarization mismatch theoretically andcompare the pros and cons between LP and CP SAR images with simulated image data.
Keywords: polarization mismatch, synthetic aperture radar, circular polarization, Faraday rotation, ionosphere

1. Introduction
Radar which is an acronym of radio raging anddetection is widely used for recent human life as thetechnology evolves, it is used not only for military
purpose but also for agriculture, hydrology,
environmental remote sensing, and etc [1]. Synthetic
aperture radar (SAR) is a kind of imaging radar that uses
microwave to detect target in remote area. As an active
sensor, SAR sensor can illuminate the target regardlessof light source (e.g. Sun), so compared to optical sensor
it can be operated regardless of day-night condition.
Furthermore, as it uses microwave that has longer
wavelength than visible light, SAR sensor can acquire
the high-resolution image of target in all-weather
condition.
To acquire the image, SAR sensor is loaded on
moving platform typically aircraft and satellite, thentransmits and receives the microwave signal along its
path. Regarding to space-borne SAR sensor which
performs its imaging mission on satellite, themicrowave of this case would traverse ionosphere andair as a medium between satellite and target on Earth.
Usually, linear polarization (LP) microwave is

Contact Author: Jae-Hyun Kim, Professor, Ph. D,
Ajou University, Won-Cheon hall, Kyeonggo-do,
Suwon-si, Yeongtong-gu, Woncheon-dong, San 5
Tel: +82-31-219-2477 Fax: +82-31-212-9531
e-mail: jkim@ajou.ac.kr

implemented for transmit signal in conventional SAR
systems. When LP microwave traverses ionosphere, thereference plane of LP microwave rotates up to 40° in
the case of L-band [5]. This rotation causes thepolarization mismatch in receiving stage, and the
impairment of transmitted and received signal causedby polarization rotation degrades SAR image quality.
The phenomenon causing the rotation on reference
plane of polarization is called the Faraday rotation (FR).
In this paper, the phenomenon called FR is explained
first then the effect of FR on SAR image is presented
next. Characteristics of LP and CP SAR systems are
introduced and by inspecting their scatteringcharacteristics the performance of CP SAR is drawn out.
2. Circular Polarization Implementation on SAR
2.1. Polarization Properties of SAR Sensors
Polarization is defined as the reference plane of
microwave in free-space due to the distribution ofcurrent and voltage on antenna. If the electromagnetic
field components of plane wave are not changed during
the propagation time it is called LP wave. LP wave canbe classified to horizontal and vertical polarization.
SAR sensor transmits and receives the microwave toacquire the image of targets. Electromagnetic wave
deals with two modes of radiation: horizontally (H) andvertically (V) polarized waves. When a radiation source
transmit and receive LP wave, an H wave impinging on
a target could produce V wave as well as H waves anda V wave interacting with a target may also yield H
waves as well as V waves. Table 1 presents the types of

OHH
OHV
OVH
OVV

Table 1. Types of LP polarizations
H mode scattering for H mode radiation
H mode scattering for V mode radiation
V mode scattering for H mode radiation
V mode scattering for V mode radiation

Table 2. Plane rotation degree due to FR
Frequency bands
Rotating degree
C-band326°
L-band40°
X-band8°

Fig.1. Polarization rotation due to Faraday rotation
LP polarizations [8]. When SAR sensor transmits H
wave, two receiving antennas for H and V backscattered waves are needed. For examples, the target
that has V components such as high-tall man madebuildings is easy to reflect H waves and less reflects theV waves. In image processing stage, the image obtained
from V back-scattered polarization wave with V
transmit signal is called VV image.
2.2. The Faraday Rotation Effect
Usually, microwave on Earth propagates through the
air as a medium, but microwave from space istransmitted and received through ionosphere that is
located between space and air. There is a phenomenon
called Faraday rotation effect which is caused byinteraction between light and magnetic field in a
medium and causes a rotation of the plane ofpolarization in the direction of propagation. Figure 1
shows the polarization rotation due to Faraday rotation.
Conventional SAR systems adopt LP microwave forits own illuminating source. It transmits LP signal andreceives back-scattered signal from target. If the SAR
sensor uses only H or V signal and receives only one
type of polarizations, it is called single-pol system.
When it transmits one type of polarizations and receives
H and V simultaneously in two receiving antennas, thissystem is called dual-pol system. Last, the system
adopts two transmitting antennas and two receiving
antennas for H and V polarization is called full-pol
system.
While LP polarization wave propagates throughionosphere, the polarization plane rotates and the
maximum degree of rotation according to frequency
bands is presented in Table 2 [2], [4].

Fig.2. Mismatch of polarization between transmitting
and receiving signals
2.3 Faraday Rotation Effect on SAR images
The full-pol space-borne SAR systems receive backscattered H and V waves. For example, if H wave istransmitted to targets, to acquire HH image SAR sensor
stores H back-scattered signal. On image processing
stage, SAR processor operates correlation process
between received signals and transmitted signals(reference signals).
Here, due to FR effect, mismatch between
transmitting (Tx) and receiving (Rx) polarization signal
occurs. For example, assume that SAR sensor transmits
H polarization wave and receives H back-scatteredpolarization wave from the target. Theoretically, theplane of both Tx and Rx signals should identical on Rx
antenna. However, while microwave traverses
ionosphere, due to FR effect, reference plane of Tx andRx polarization rotates and consequently FR causespolarization mismatch on receiving antenna.
Polarization mismatch lowers the amplitude of Rx
signal when it compared to Tx polarization plane.
Mismatch between Tx and Rx is depicted in Figure 2.
Due to the mismatch there occurs polarization
mismatch loss between polarization vectors. It degrades
image quality such as image blurring, image brightness
degrading, and etc.
2.4 CP-SAR Implementation
There is circular polarization wave that is utilizedwith two, orthogonal components: right- and lefthanded circular polarization (RHCP and LHCP). It isTable 4. Parameters of point target analysis
Parameters
Value
Center frequency
1.27 GHz
Bandwidth
10 MHzPRF
2346.3 Hz
Pulse width
30 us
Azimuth beamwidth
1.4989°Range beamwidth
2.9979°Altitude
600 kmPixel size
1024 x 1024

Fig.3. Definition of axial ratio
Table 3. Dataset of SAR image comparison
Parameters
Specification
Satellite
ALOS PALSAR
Data
PLR 1.1
Data size
18432 (row) x 1088 (col)Output format
8-bit BMP
Processor
PolSARPro v4.2, MATLAB
frequently used in EME (Earth-Moon-Earth)communications and here CP wave implementation on
SAR will be presented. Electric field (E-field) andmagnetic field (M-field) of CP are perpendicular eachother in their propagation direction and the reference
plane of CP is circle shape. The characteristics of eachtype of polarization can be defined by axial ratio thatindicate the proportion between E-component and Mcomponent. Definition of axial ratio is defined as
ε = 𝑐𝑜𝑡 −1 (𝑅)(1)where ε = ellipicty angle (−45° ≤ ε ≤ 45°)
R = value of axial ratio
Because a circle has one same radius in it, axial ratioof CP wave equals 1 [4]. Figure 3 shows definition of
axial ratio.
Polarization mismatch loss described in dB scale isdefined as (2).

1   w2  A2  2  w  A cos 2  ( dB ) 10 log 1   w2  2A  (2)

 w and  A represent the circular polarization
ratio of the transmitted wave and the circularpolarization ratio of receiving antenna respectively.
Each circular polarization ratio is defined as follow.
 w   rw  1 rw  1
 A   rA  1 rA  1(3)

rw and rA indicate axial ratio of transmitted wave
and axial ratio of receiving antenna respectively.
Assuming that axial ratio of CP equals 1, thepolarization mismatch loss is eliminated completely.

Fig.4. Comparison of CP images (1st row) and LP images(2nd row)
2.5 Simulation and results
Dataset of simulation is defined in Table 3. To
compare the LP and CP image, full-pol LP SAR images
are used. First, raw data from ALOS PALSAR(Advanced Land Observing Satellite Phased Array Lband SAR) is converted to four SLC (single lookcomplex) images by using PolSARPro V4.2 tool. Eachgrey-scale image represents polarization types oftransmission source and back-scattered components. By
converting the scattering matrix from LP to CP with (4),CP images can obtained with MATLAB [6].

OLL
O
 RL

OLR  1 1 j  OHH
ORR  2  j 1   OVH

OHV  1 j 
OVV   j 1 

(4)

To compare the image quality with in the sense ofcontrast and brightness, CP and LP images are presented
in Figure 4. Among the images, especially LL (CPimage) and HH (LP image) images show remarkabledifference of brightness and contrast.
Not only compare the image as it is but also analyze
the point target characteristics, simulation was donewith the parameters in Table 4.

Table 5. Dataset of point target analysis
Parameters
PSLR (dB)CP azimuth samples-17.52 dB
LP azimuth samples-14.01 dB
CP range samples-35.98 dB
LP range samples-27.86dB

Fig.5. Azimuth sample PSLR of CP and LP

Fig.6. Range sample PSLR of CP and LP
Back-scattered signal strength of CP and LP arecompared in Figure 5 and Figure 6 in the sense of PSLR
(peak to side-lobe ratio). PSLR indicates the difference
between normalized main-lobe peak value and largest
side-lobe value. PSLR is a kind of barometer that canevaluate the performance of SAR signal. Parameters
used for point target analysis is presented in Table 5.
Assuming the one point target is in the field, PSLR iscalculated. In the case of azimuth sample, PSLR of LP,-14.01dB, is changed to -17.52dB in CP case. Likewise,
range sample PLSR of CP is enhanced from -27.86dB
to -35.98dB.
3. Conclusions
In this paper, polarization mismatch loss caused by
Faraday rotation is investigated that it degrades SAR
image quality. Conventional SAR systems implemented
with LP microwave suffer from FR that rotates thepolarization plane. CP-SAR that utilizes circularly
polarized microwave is proposed and images of LPSAR and CP-SAR are compared. Comparing the PSLR
of azimuth and range samples respectively, in azimuth
sample case, PSLR of CP has increased -3.53dB and inrange case, PSLR of CP has increased -7.12dB. By
comparing the simulation results, it is shown that theimage obtained from CP-SAR performs better thanconventional LP-SAR when FR occurs andconsequently it means that CP-SAR system is robust to
FR because this system can eliminate the polarization
mismatch loss ideally. Still, performance evaluation
methods such as comparing IRF (impulse response
function), PLSR, and ISLR (integrated side-lobe ratio)
are needed to verify the CP image quality. Next research
step will be the precise quantitative analysis on CP-SAR
performance.
4. References
1) H. I. Yang, D. G. Lee, T. H. Kim, J. T. Sri Sumantyo
and J. H. Kim (2014) Semi-automatic Coastline
Extraction Method Using Synthetic Aperture Radar
Images, in Proc. ICACT 2014, pp. 678-681
2) J. T. Sri Sumantyo (2012) Development of
Circularly Polarized Synthetic Aperture Radar
Onboard Unmanned Aerial Vehicle (CP-SAR UAV),in Proc. IGARSS 2012, pp. 4762-4765
3) Yohandri, V. Sissan, I. Frimansyah, P. Rizki Akbar,
J. T. Sri Sumantyo and H. Kuze (2011) Development
of Circularly Polarized Array Antenna for Synthetic
Aperture Radar Sensor Installed on UAV, Progressin Electromagnetics Research C, Vol. 19, pp. 119133
4) P. Rizki Akbar, J. T. Sri Sumantyo and H. Kuze
(2010) CP-SAR UAV Development, International
Archives of the Phrotogrammetry, Remote Sensing
and Spatial Information Science, Vol. XXXVIII,Part 8, pp. 203-208
5) H. I. Yang, J. T. Sri Sumantyo and J. H. Kim (2014)
Development of CP-SAR (Circularly Polarized
Synthetic Aperture Radar) System, in Proc. ISRS
20146) Y. Yosio (2007) Radar Polarimetry from Basics toApplications: Radar Remote Sensing using
Polarimetric Information, Society of Electronics andInformation Communications, pp. 172-179
Acknowledgement
This research was supported by NSL (National SpaceLab) program through the National Research
Foundation of Korea funded by the Ministry of
Education, Science and Technology (2012-0009092)
and by KARI (Korean Aerospace Research Institute)
through the Ministry of Science, ICT and Future
Planning.

International cooperative studies on environment and disaster mitigation
with satellite remote sensing
Fusanori Miura1, Tasuku Tanaka2, Made Sudiana Mahendra3 and Takahiro Osawa4
1Vice President, Professor, Graduate School of Science and Engineering. Yamaguchi University, Tokiwadai 2-16-1,

Ube, Yamaguchi, 755-8611 Japan, Visiting Professor of Udayana University
2Professor, Graduate School of Science and Engineering. Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi,

755-8611 Japan, Visiting Professor of Udayana University
3Professor, Graduate School of Environmental Science, Udayana University, Jalan PB Sudirman, Denpasar, Bali,

80232 Indonesia, Visiting Professor of Yamaguchi University
4Doctor, Center For Remote Sensing and Ocean Sciences (CReSOS), Udayama University, Jalan PB Sudirman,

Denpasar, Bali, 80232 Indonesia, Visiting Associate Professor of Yamaguchi University

Abstract
The center for Remote Sensing and Ocean Science (CReSOS) was established in Udayana
University (UNUD) in 2003 with the aid of Japan Aerospace Exploration Agency (JAXA ) andNational Institute of Aeronautics and Space of Indonesia (Lembaga Penerbangan Dan Antariksa
Nasional: LAPAN). According to the objectives of CReSOS, JAXA started pilot project in 2003 andcontinued it until 2008. During the period, an education program on satellite remote sensing
technology has been established in a master course of UNUD. At the same time, international
cooperative research has also started between UNUD and Japanese research institutes. UNUD and
Yamaguchi University (YU) established joint master course program in 2009 with the support ofGrant from Japanese Government under the title of “International Graduate School Cooperation by
Satellite Remote-Sensing”. Then UNUD and YU expanded the educational program into the double
degree program in 2011. Some students in the program move to YU and study in the second
academic year. After getting master degrees from both UNUD and YU, some of them go to Doctoral
course and acquire PhD. Many valuable papers have been published through the program. The
program is now expanded not only for Indonesian students but also for students in Southeast Asia
countries.
Keywords:
Keywords Satellite remote sensing, International cooperative education and research,
Environmental and natural disaster issues

Introduction
The center for Remote Sensing and Ocean
Science (CReSOS) was established in Udayana
University (UNUD) in 2003 with the aid ofJapan Aerospace Exploration Agency (JAXA)
and National Institute of Aeronautics andSpace of Indonesia (Lembaga Penerbangan
Dan Antariksa Nasional: LAPAN). Professor
Yasuhiro Sugimori (professor emeritus of Chiba
University) is the first Director of CReSOS.
Unfortunately he pass away in 2008 and prof.
Tasuku Tanaka succeeded him.
In the year 2009 Yamaguchi University (YU)won the Japanese government fund for International Cooperation for Space Technology.
Contact Author: Fusanori Miura, Professor,
Graduate school of Science and Engineering,
Yamaguchi University, 2016-1, Tokiwadai, Ube
755-8611, Japan
Tel: 81 836 85 9536 Fax: 81 836 9536
e-mail: miura@yamaguchi-u.ac.jpYamaguchi

Based on this fund UNUD and YU established“Joint Master Course for Environment andDisaster Mitigation Research”.
In the year 2012 YU won another Japanese
government fund. We are now planning how tofurther enhance the current cooperation
between UNUD and YU.
Establishment of CReSOS
The objectives of CReSOS are;1) to initiate training and education for humanresources development and to enhance theimage of Bali island as tourist destination,science and technology promotion.
2) to initiate regional and international
collaboration among scientists in the field of
remote sensing.
3) to invite the researchers from all over theworld to do research related to application of
remote sensing.
4) host seminars, workshops and conferences.
According to the objectives of CReSOS, JAXA

started pilot project in 2003 and continued it
until 2008. During the period, an education
program on satellite remote sensing technology,
the theory and its applications, has been
established in a master course of UNUD. At thesame time, international cooperative research
has also started between UNUD and Japanese
research institutes. The research fields/topics
were wide as follows;a. Bio-diversity of coastal waters in Bali andneighboring islands.
b. Monitoring and exploration of the marine
resources and environment.
c. Empowering the society in coastal areas toincrease their productivity.
d. To attain better understanding of thesea-dynamic, land- atmospheric interaction.
e. Coastal zoning particularly in the region ofSoutheast Asia.
As can be seen from the above, the research
fields/topics were limited to those have been
related to the ocean science at first, but havebeen expanded to disaster mitigation.
We have also established the cooperation
with Indonesia Ministry of Education, Bureau
of International Cooperation (DIKNASA).
Joint Master Course
In 2009, as mentioned in Introduction,
UNUD and YU established joint master course
program with the support of Grant fromJapanese Ministry of Education, Culture,
Sports, Science and Technology (MEXT) under
the title of “International Graduate School
Cooperation by Satellite Remote-Sensing”.
Then UNUD and YU expanded the educational
program into the double degree (DD) programin 2011. Some UNUD students who take the
DD program move to YU and study in thesecond academic year. During the stay in YU,
they write the first master thesis and then go
back to UNUD to write the second thesis at theend of the second year. After getting master
degrees from both UNUD and YU, some ofthem enter Doctoral course and acquire Ph.D.
in YU. Through these educational and research
activities, many valuable fruits have beenobtained. Main published papers are listed at
the end of this paper. The program is now
expanded not only for Indonesian students but
also for students in Southeast Asia countries.

Joint master course education program
To start the education program, we needed toknow differences in education system between
UNUD and YU and then to adjust them. The
organizations which are responsible to theprogram and the academic system in both

universities are as listed in Table 1.
Table 1 Responsible organizations and academic
systems in both universities.

The required units in both universities arealso different and are listed in Table 2.
Table 2 Required units for master degree.

Ten subjects (20 units) listed in Table 3 were
designated as sharedlectures. These lectures
are delivered simultaneously both to Sudirman
campus (Denpasar city) of UNUD and Tokiwa
campus (Ube city) of YU through the remote
lecture system which we developed using
internet. At most students of UNUD work indaytime, the shared lectures start at 15:10 inBali time (16:10 in Japan time). Two classes are
given per day. To perform the shared lecture,
many professors and experts participate andcontribute not only from UNUD and YU but
also from other organizations such as JAXA,
Hokkaido University, University of Tokyo,
Chiba University, Tokai University and soforth.
Photograph 1 shows a snapshot taken after
the shared lecture in UNUD. The back screen
is the classroom in YU.

Double degree program
By expanding and making use of the joint

Table 3 Subjects of the joint master course
education program,

program, students in UNUD can obtain the
degree of Mater of Engineering (ME) from YU,
and Master of Science (MS) from UNUD bystaying one year in YU in the second academic
year. The DD students can bring 10 units when
they are enrolled in YU, that is, they need totake more than 20 units in YU. After finishing
the master thesis, they come back to UNUD
and starts study for the second master thesis.
To make it easier, joint research tutorial
system is provided. In addition, some
professors were entitled as “Visiting (associate)
professor” each other. Photography 2 shows theceremony of the certification.
As there is no Ph.D. course for environment
or disaster mitigation in UNUD, most DD
students go to Ph.D. course in YU. The numberof DD students is as follows;
Class 2010: 3 students and2 students in Ph.D. in YU
Class 2011: 3 students and2 students in PhD in YU
Class 2012: 3 students
Class 2013: 3 students
The activities by the students have promoted
the international cooperative research between
UNUD and YU and bore fruitful results as
explained in the next section and listed at theend of this paper

Joint master course education Research

Photo.1 A snapshot taken after a shared lecture.

The research topics are rich in variety as
Ocean environment & fishery, Climate change
and oceanography, Weather and land process,Precipitation and natural disasters, Disastermitigation, such as tsunami disasters, flood,and so forth.

(1) Ocean environment & fishery

Figure 1 shows one of the examples of theresults from this research theme. It shows therelationship between the number and locationsof Big-eye tuna caches and the spatial
distribution of Sea Surface Temperature(SST)in Indian Ocean in March (left) and August(right) in 2010. This research combines thefishery and satellite remote sensing technology.
By making use of these results, Efficient andsustainable fishery is expected.

(2) Climate change and oceanography

Photo.2 Ceremony of the certification of visiting
professor.

master course education program, we designed
the double degree (DD) program. In the DD

It is thought that the temperature of theocean around Indonesian archipelago may havestrong effect to the world climate. Figure 2
shows the seasonal variability of SST, U-WS
and RR in the Indian and Pacific oceans at theobserved locations. The variability is average often years observation. These basic data will be
useful to understand the cause of abnormal
climate phenomena such as El Nino, La Ninaand so forth.

Fig.1 Relationship between the number and locations of Big-eye tuna caches and the spatial
distribution of Sea Surface Temperature(SST)

Fig.2 seasonal variability of SST, U-WS and RR in the Indian and Pacific oceans aroundthe Indonesian archipelago

Fig.3 relationship between rainfall and occurrence of flood

(3) Precipitation and groundwater level

Figure 3 shows the relationship between therainfall and the occurrence of the flood. The
time history (upper left figure) and the space
distribution (right figure) of the rainfall wereobserved by GSMaP. This kind of research will
be useful to understand the mechanism of theoccurrence of flood and disaster reduction.

(4)Disaster mitigation(a) Tsunami inundation area

On March 11 in 2011, a magnitude nine (M9)earthquake attacked the north-east Japan areaand severe tsunami devastated very wide area.
To determine the attached area by tsunami isvery important to grasp the damaged area anddamage situation of there. Figure 4 illustrates
the obtained inundation area by the tsunami in
Rikuzentakata city. Figure(a) is a true-color
image obtained from ALOS-AVNIR-2. Green
area in Fig.4(b) represents the inundation areaby using NDVI. Figure4(c) represents theinundation area (white zone) from ALOSPALSAR.

(b) Fool inundation area

Fig. 4(a) True-color image of Rikuzentakata
after the tsunami attack.

Figure 5 shows an example analysis of floodinundation area caused by heavy rain in
Thailand in 2011. Figure (a) is the image before
the occurrence of the flood and (b) that after theoccurrence of the flood. They were obtainedusing NDVI. Blue area represents water zone
while red area vegetation zone.

Fig. 4(b) NDVI image of the inundation area
due to the tsunami.

Fig. 5(a) Before the heavy rain

Fig. 4(c) The inundation area obtained from
SAR image.

Fig. 5(b) Inundation area after the heavy rain

New Initiative
In 2013, Yamaguchi University won anotherJapanese Government Fund for enhancing theInternational Collaboration. We are planning
to invite the master course students from theSouth-East Asian countries, such as Thailand,
Malaysia, Vietnam, Philippine, and east Timor
to the new academic year 2014 from September
2014. We, Yamaguchi University and Udayana
University, jointly enlarge cooperation with theIndonesian Government, Research Institutes
and Universities. We are now under way to sign
the MOU for cooperation with Ministry of
Finance, Indonesia.
The use of Synthetic Aperture Radar (SAR) is
promising for the research on Environment andDisaster mitigation, in particular, by virtue ofthe recently launched ALOS-2 satellite data.
In 2012, the sister cooperative project,“Restoration of Deforest Areas by Symbiosis
Technology”” emerged from the current joint
project. We have established the pilot site on
Batur Mountain north of Bali Island.
Through the cooperative activity, YU joined
Sentinel Asia and was assigned as a memberof Data Analysis Node (DAN) as the first
university in Japan, and have contributed byproviding useful imaged through the web-site.
Summary
We reviewed the joint educational andresearch projects between Udana andYamaguchi University since 2003. From thisproject, we accomplished:(1) Mutual understandings between two
countries;(2) New findings in environment and disastermitigation research in the South-East Asia;(3) Growing up young Scientists(4) Confirmation of capability of spacetechnology for environment and disastermitigation research.
We are looking forward to expanding thecurrent project to the South-Asian countries
and other research institutes and universities.
Acknowledgements
Many professors, experts and organizations
participate and contribute to the joint project
between Udayana University and Yamaguchi
University. Without their cooperation and help,
this project would not be succesful. The authors
express deepest thanks to all of them.
List of main
main published papers
1) A. R. As-Syakur, T. Tanaka, R. Prasetia, I. K.
Swardika & I. W. Kasa “Comparison of TRMM
multisatellite precipitation analysis (TMPA)
products and daily-monthly gauge data overBali” International Journal of Remote Sensing,
Vol.32, pp. 8969-8982, 2011.
2) N. W. Ekayanti, T. Tanaka , A. R. As-Syakur, A.
R. As-Syakur & T. Osawa, “Application of

ALOS/PALSAR to estimate carbon dioxidetransfer velocities compared with satellite windspeed data 2007-2008”, International Journal of
Remote Sensing, Vol.32, pp. 9789-9800, 2011.
3) I. K. Swardika, T. Tanaka & H. Ishida “Studyon the characteristics of the Indonesian seasusing satellite remote-sensing data for 1998–
2007”, International Journal of Remote Sensing,
Vol.33, pp. 2378-2394, 2012.
4) W. G. Astawa Karang, F. Nishio, L. Mitnik, & T.
Osawa, “Spatial-temporal distribution andcharacteristics of internal waves in the Lombok
Strait area studied by Alos-Palsar images”
Earth Science Research, Vol. 1, No. 2, pp.11-22,
2012.
5) I. A. G. Jayanti, T. Osawa, I. W. S. Adnyana, T.
Tanaka, I. W. Nuarsa, & A. R. As-Syakur,“Multitemporal MODIS Data to mapping rice
field distribution in Bali province of Indonesia
based on the temporal dynamic characteristicsof the rice plant”, Earth Science Research, Vol.
1, No. 1,pp. 64-74, 2012.
6) I D. N. Nurweda Putra & T. Tanaka “The local
characteristics of Indonesia sea and its possible
connection with ENSO and IOD: Ten years
analysis of satellite remote sensing data” Earth
Science Research; Vol. 2, No. 2, pp.153-180,
2013.
7) A. R. As-Syakur , T. Tanaka , T. Osawa, & M. S.
Mahendra “Indonesian rainfall variability
observation using TRMM Multi-Satellite Data”
International Journal of Remote Sensing, vol.
34, pp. 7723-7738, 2013.
8) A. B. Sambah, F. Miura, “Remote sensing, GIS,
and AHP for assessing physical vulnerability totsunami hazard”, International Journal of
Earth Science and Engineering, Vol.7, No.10,
pp.17-25, 2013.
9) A. B. Sambah and F. Miura, “Comparison ofdifferent DEM data for tsunami vulnerability
mapping using GIS and Analytical Hierarchy
Process”, The 34 Asian Conference on Remote
Sensing, Bali, Indonesia, October, 2013.
10) A B. Rimba and F. Miura, “Predicting Flood
Vulnerable Areas by Using Satellite Remote
Sensing Images In Kumamoto City–Japan”,
The 34 Asian Conference on Remote Sensing,Bali, Indonesia, October, 2013.
11) D. Setiawati, F. Miura and P. Aryastana,“Verification of hourly GSMAP rainfall
estimated during the flood events in Kumamoto
Prefecture, Japan”, The 34 Asian Conference on
Remote Sensing, Bali, Indonesia, October, 2013.
12) A. B. Sambah and F. Miura, “Remote sensing
and spatial multi-criteria analysis for tsunami
vulnerability
assessment”,
EMERALD,
Disaster Prevention and Management, Vol. 23,
Issue 3, 2014.
13) A. B. Sambah and F. Miura, “Integration of
spatial analysis for tsunami inundation andimpact assessment”, Journal of Geographic
Information System, Vol.6, No.1, pp.11-22,
2014.

Contact Person
Prof. Josaphat Tetuko Sri Sumantyo, Ph.D
Center for Environmental Remote Sensing, Chiba University
1‐33 Yayoi, Inage, Chiba 263‐8522 Japan
Tel. +81 (0)43 290 3840 / Fax +81 (0)43 290 3857
Email jtetukoss@faculty.chiba‐u.jp
Website http://www2.cr.chiba‐u.jp/jmrsl/

Fusanori Miura
Yamaguchi University“International cooperative studies onenvironment and disaster mitigation withsatellite remote sensing