KOMPSAT-5 (Korea Multi-Purpose Satellite-5) / Arirang-5
Land surface topography
Land surface imagery
Launched in August 2013, KOMPSAT-5 is part of the Korean National Development Mission Plan by the Ministry of Education, Science and Technology, developed by the Korea Aerospace Research Institute (KARI). The primary objective of the mission is the operation of a SAR (Synthetic Aperture Radar) imaging satellite for the monitoring of environmental disasters. KOMPSAT-5 is often referred to as the GOLDEN mission, due to the characteristic aspects of the mission: GIS (Geographic Information System), Ocean, Land management, Disaster and Environmental monitoring.
|Mission status||Operational (nominal)|
|Launch date||22 Aug 2013|
|End of life date||22 Aug 2022|
|Measurement category||Landscape topography, Multi-purpose imagery (land)|
|Measurement detailed||Land surface topography, Land surface imagery|
|Instrument type||Imaging microwave radars|
|CEOS EO Handbook||See KOMPSAT-5 (Korea Multi-Purpose Satellite-5) / Arirang-5 summary|
KOMPSAT-5 carries three instruments: Corea SAR Instrument (COSI), the Atmosphere Occultation and Precision Orbit Determination (AOPOD), and the Laser Retro-Reflector Array (LRRA). COSI is a multi-mode X-band instrument that provides high-resolution SAR imagery in various modes, fulfilling the primary objective. COSI provides viewing of landscape topography and multi-purpose land imagery for land applications of cartography and disaster monitoring. AOPOD is a spaceborne, dual frequency GIS receiver, which together with the LRRA form the secondary payload.
The Corea SAR Instrument (COSI) operates in three specific modes, allowing the instrument to provide SAR imagery in varying resolution and swath widths.. The standard SAR mode has a spatial resolution of 3 m and swath width 30 km, the wide-swath SAR mode has resolution of 20 m and swath 100 km, and the high-resolution SAR mode has a resolution of 1 m and swath 5 km. The satellite has an incidence angle of 45° and an angle range of 20° - 45° (nominally) and 45° - 55° (extended). The instrument has a mass of 520 kg and a design life of 5 years, which it has outlasted.
KOMPSAT-5 operates in a sun-synchronous orbit of altitude 550 km, inclination 98.1° and LST (Local Solar Time) of 0600 hours. It also has an orbital period of 98.5 minutes, and a repeat cycle of 28 days.
Space and Hardware Components
The KOMPSAT-5 Ground Segment (KGS) is developed by the Electronics and Telecommunications Research institute (ETRI) (operated by KARI) and consists of the Mission Control Element (MCE), the Image Reception and Processing Element (IRPE) and the Calibration and Verification Element (CVE). These specific elements provide mission planning, orbit determination/predictions and allow for the utilisation of the Precise Orbit Determination (POD) function. Ultimately, the KGS processes and analyses KOMPSAT-5 payload data and has a system ability to generate level products from raw data within an hour, an important feature for event monitoring of land processes. KOMPSAT-5 utilises a bus designed by KARI, in collaboration with contractors such as Korea Aerospace Industries, Korean Air, Hanwha, Doowon Heavy Industries, and SI (Satrec Initiative). The bus contains the SMS (Structure and Mechanisms Subsystem), the TCS (Thermal Control Subsystem), EPS (Electrical Power Subsystem), AOCS (Attitude and Orbit Control Subsystem), PS (Propulsion Subsystem), TC&RS (Telemetry Command and Ranging Subsystem), and FSW (Flight Software) subsystems.
KOMPSAT-5 (Korea Multi-Purpose Satellite-5) / Arirang-5
KOMPSAT-5 is part of the Korean National Development Plan of MEST (Ministry of Education, Science and Technology) which started in 2005. The project is being developed and managed by KARI (Korea Aerospace Research Institute). The primary mission objective is to develop, launch and operate an Earth observation SAR (Synthetic Aperture Radar) satellite system to provide imagery for geographic information applications and to monitor environmental disasters. 1) 2) 3)
KOMPSAT-5 is also referred to as the GOLDEN mission:
- GIS: Acquisition of independent high resolution SAR images
- Ocean & Land Management : Survey of natural resources
- Disaster & ENvironment Monitoring : Surveillance of large scale disasters and its countermeasure.
In March 2006, KARI signed a contract with Thales Alenia Space of Italy, TAS-I (formerly Alcatel Alenia Space), to provide an X-band SAR payload system for multi-mode observations, including the data link subsystem for gathering the data transmitted by the radar, archiving them and subsequently transmitting them to the ground station. In addition, the company will also provide the ground SAR image processor as well as the calibration algorithms and equipments. 4) 5)
The KOMPSAT-5 spacecraft bus design, development and integration is being led by KARI. The private companies such as Korea Aerospace Industries, Korean Air, Hanwha, Doowon Heavy Industries, and SI (Satrec Initiative), which have already participated in the former Korean satellite programs, are involvied in the development of the KOMPSAT-5 spacecraft. Based on the experience of the previous programs, core technologies for satellite bus were enhanced during the development of KOMPSAT-5. 6) 7)
The KOMPSAT-5 spacecraft bus is of modular design and of KOMPSAT-2 heritage. The bus allows parallel integration of equipment. The bus subsystems consists of the SMS (Structure and Mechanisms Subsystem), the TCS (Thermal Control Subsystem), EPS (Electrical Power Subsystem), AOCS (Attitude and Orbit Control Subsystem), PS (Propulsion Subsystem), TC&RS (Telemetry Command and Ranging Subsystem), and FSW (Flight Software). The spacecraft has a launch mass of ~1400 kg, the design life is 5 years.
EPS (Electric Power Subsystem): EPS consists of three major components, the solar array, the battery, and the PCDU (Power Control and Distribution Unit).
- The solar array consists of two wings, each comprising four solar panels supported by a boom and attached to SADA (Solar Array Drive Assembly). The SADA rotates the wings and electrically connects their solar cell circuit, via junction box, through slip rings to the main bus. The SADE (Solar Array Drive Electronics) control the drives for sun tracking. The solar panels are populated with silicon solar cells electrically connected into strings. The spacecraft generates an average on-orbit power of 1.4 kW (EOL).
- The battery consists of 13 cells with 4 parallel Li-ion cells, cell bypass circuitry, and monitoring electronics. The battery has a capacity of 97 Ah (EOL)
- The PCDU perform the following major functions: It protects the battery from overcharging by the active control of the solar array generated power and it distributes the unregulated (+50 V) and the regulated electrical power (+28 V) to the bus and payload units via the controlled unit load switch. The PCDU also provides the secondary power for the TDE (Torque Drive Electronics) and TAM (Three Axis Magnetometer).
RF communications: The TC&RS data are transmitted in S-band (4 kbit/s), while the payload data are downlinked in X-band at 310 Mbit/s.
The KOMPSAT-5 (Arirang-5) spacecraft was launched on August 22, 2013 on a Dnepr-1 launch vehicle of ISC Kosmotras from the Dombarovsky Launch Site, Yasny, Russia. The launch was executed by the Russian Strategic Rocket Forces of the Russian Ministry of Defense with the support of the Russian and Ukrainian companies, which are part of the ISC Kosmotras industrial team. 9) 10) 11) 12)
This marked the first flight of the Dnepr-1 launcher since August 2011. Dnepr-1 launches had been suspended in 2011 by the Russian Defense Ministry based on the financial aspects of the program. Subsequently, in May 2013, it was decided by the Russian and Ukrainian governments to undertake the two launches.
- The first launch took place on 22 August 2013 and placed the Korean Arirang-5/KOMPSAT-5 satellite into orbit.
- The second launch (Nov. 2013) will place a cluster of small satellites into orbit with DubaiSat-2 of EIAST (Dubai) and STSat-3 of KARI (Korea) as the primary payloads.
Orbit: Sun-synchronous near-circular dawn-dusk frozen orbit, mean altitude = 550 km, inclination = 97.6º, nodal period = 95.78 minutes (15 1/28 orbits/day), LTAN (Local Time on Ascending Node) = 6 hours, the repeat cycle is 28 days. 13) 14)
• January 29, 2019: Ursa Space Systems, Inc. (Ursa) of Ithaca NY (USA) and SIIS (SI Imaging Services) of Daejeon, Korea have signed a multi-year contract, establishing Ursa's continued access to KOMPSAT-5 radar satellite imagery, distributed exclusively by SIIS. 16)
- This contract renews a long-standing partnership, extending back to Ursa's beginnings as a satellite imagery analytics company and the companies are excited to continue to partner to provide intelligence, analytics, and new insights as Ursa's technology creates new products for a wide range of industries. SIIS was an early partner in Ursa's global network and their radar imagery is leveraged across Ursa's suite of analytics products.
- "We had established this partnership in May 2017 in order to provide KOMPSAT-5 radar data that helps Ursa provide value-added services to customers," explained Wook-Hyun Choi, CEO and president of SI Imaging Services."Ursa has been a great partner in using KOMPSAT-5 data and extracting meaningful information out of it."
- Among other things, Ursa's products offers insight into the global oil supply chain. Their leading product, Global Oil Storage Monitoring provides customers with weekly measurements of crude oil storage in 150 locations worldwide. The resulting increased transparency in energy markets has improved decision making for consumers.
- "SIIS has proved a valuable and reliable partner over the course of Ursa's growth," said Derek Edinger, Ursa co-founder, and chief strategy officer. "The SIIS contribution to our radar satellite network has enabled us to pursue our mission of providing accurate, meaningful intelligence to customers."
• The KOMPSAT-5/Arirang-5 spacecraft and its payload are operating nominally in January 2019. SIIS (SI Imaging Services), a subsidiary of SI (Satrec Initiative), is the exclusive worldwide marketing and sales representative of the KOMPSAT series KOMPSAT-2, KOMPSAT-3, KOMPSAT-3A and KOMPSAT-5. 17)
• The KOMPSAT-5/Arirang-5 spacecraft and its payload are operating nominally in January 2017. 18)
• The KOMPSAT-5 spacecraft and its payload are operating nominally in March 2016. According to KARI, the spacecraft will be operated safely throughout 2016 and in the coming years. KOMPSAT -5 acquires the imagery on a global scale and downlinks the data to the KARI and Svalbard ground stations for public and commercial use. 19)
• Feb. 29, 2016: The chairman of DLR (German Space Agency) and the president of KARI signed an agreement authorizing DLR/DFD to acquire in Neustrelitz data from Korean Earth observation missions. The ceremony took place on 23 February at KARI headquarters in Daejeon, Korea. The agreement specifies that a KARI OGST (Overseas Ground Station Terminal) is to be established in Neustrelitz (DLR site in Germany). OGST hardware and software will make possible the digital processing of data from Korean earth observation satellites received at the antennas in Neustrelitz. In addition, command sequences prepared in Korea can be sent to the satellite from Neustrelitz. A high-rate Internet link guarantees the smooth exchange of data between Neustrelitz and Daejeon. 20)
- At present, the Korean earth observation program consists of KOMPSAT satellites. These yield high-resolution images in the optical, thermal, and X- band SAR ranges. The current KOMPSAT-5 SAR mission will be augmented by KOMPSAT-6 in the coming years. The KOMPSAT-6 instrument will be supplied by Airbus DS and is an upgrade of the TerraSAR-X instrument.
- Work on setting up OGST in Neustrelitz has started. Full implementation and data acquisition is planned for the end of 2016.
• Feb. 1, 2016: The KOMPSAT-5 project has started with InSAR acquisitions and the SIIS project has received a review from an end-user about the products. UH(Ultra High Resolution), EH(Enhanced High Resolution), HR(High Resolution) products were provided, and they showed great results. 21)
• May 20, 2015: The KOMPSAT-5 spacecraft mission is operational and KARI will soon make an official announcement for commercial distribution (Ref. 22).
• March 30, 2014: The KOMPSAT-5 project has completed the calibration and validation phase. Currently, KARI and SI are performing beta testing (this involves testing of the imagery over certain areas in different modes based on speculative imaging requests and independent quality assessment). Most probably, within 1-2 months, SI will start the commercial distribution of KOMPSAT/Arirang-5 imagery worldwide. 22) 23)
• Dec. 19, 2013: KARI released SAR images acquired for calibration purposes. During the early operation and calibration phase, all of the satellites functions have been verified and the satellite is now under payload calibration. The released images are acquired for the verification of payload performance. 24) 25)
- The KOMPSAT-5 CAL/VAL team will complete the calibration of the radar instrument and optimizing the data processing chain by the end of February 2014. After completion of calibration, KOMPSAT-5 will be operated to provide products for various applications such as security and defense, image interpretation, mapping, land and natural resource management, environmental monitoring, disaster monitoring and more. Commercial data from KOMPSAT-5 can be expected to be available from the second quarter of 2014.
• The KOMPSAT-5 spacecraft made contact with a ground station in the Asian country early Friday (Aug. 23, 2013), confirming its successful deployment into its target orbit, officials in Yasny said. 26)
Beacon signals from the satellite were initially picked up by the Troll Satellite Station in Antarctica, 32 minutes following the launch, partly indicating the satellite's successful deployment into its orbit. 27)
COSI (Corea SAR Instrument)
COSI is a multi-mode X-band instrument provided by TAS-I (Thales Alenia Space-Italy) as prime contractor (Ref. 2). The primary objective of the COSI assembly is to provide high resolution SAR imagery in various modes at an incidence angle of 45º (Ref. 1): 28) 29)
- High resolution SAR mode imagery: 1 m (also known as spot SAR mode)
- Standard SAR mode imagery: 3 m (stripmap mode)
- Wide swath SAR mode imagery: 20 m (ScanSAR mode).
The COSI payload consists of the SSS (SAR Sensor Subsystem) and the DLS (Data Link Subsystem). The SSS operates in X-band and is equipped with an active phased array antenna with electronic scanning capabilities in the azimuth and elevation planes. The DLS is in charge of source data storage (and ancillary data) and transmission to the ground segment.
Without the payload module structure
Peak power consumption
Average power consumption
2 minutes operation and downlink
9.66 GHz (X-band) or 3.2 cm wavelength
Standard mode imagery
3 m GSD, 30 km swath width
High resolution mode imagery
1 m GSD, 5 km swath width
Wide swath mode imagery
20 m GSD, 100 km swath width
Image acquisition time
2 continuous minutes per orbit
Selectable among: HH,HV, VH, VV
Incidence angle range (look angle)
Providing a potential nominal coverage region of 185-490 km from nadir
NESZ (Noise Equivalent Sigma Zero)
≤ -17 dB
On-board data memory
EOL (End of Life)
Downlink data rate
Resolution (GR) @ 45º incidence angle
Swath width @ 45º incidence angle
No of beams
No of beams
High Resolution (HR)
The incidence angle range of the steerable beam is from 20-45º nominally so that the ground coverage will be, when measured from nadir, covers a potential coverage region from 185-490 km (305 km wide) for the nominal support, and 490-675 km (185 km wide) for extended beam steering (Figure 12).
Thanks to the wider coverage of up to 490 km width in a single orbit than the 95-km distance between adjacent passes (at equator), a ground target can be imaged several times with multiple incidence angles, which is required for radargrammetric configuration.
In addition, the agile KOMPSAT-5 spacecraft has a body pointing capability in cross-track which offers a left or right-looking observation capability. This feature is of great importance for event monitoring - doubling in effect the FOR (Field of Regard). 31)
CalVal (Calibration and Validation) of COSI: The first SAR mission of Korea requires special attention for successful mission operations support. The CalVal activities include relative and absolute radiometric calibration and pointing calibration. The mission uses DT (Distributed Targets) and PT (Point Targets). COSI employs a total of 50 radar beams, 19 beams are being used for the HR (High Resolution) mode, while 31 beams support the standard imaging mode. In the WS (Wide Swath) mode, a combination of 19 beams of the standard mode are being used.
On the basis of the antenna model, all modes supported will be validated in the IOT (In-Orbit Test) phase. The DT and PT imagery of the various test sites will represent the key inputs for the CalVal activities. 32) 33)
KARI selected fixed ground CalVal sites in the Mongolia steppe region for the positioning of CRs (Corner Reflectors). These CalVal sites will be used periodically by the COSI instrument during the KOMPSAT-5 mission life time (5 years). The CalVal sites were selected due to their characteristics: flat area, no man-made structures, and low backscattering coefficient.
- Each trihedral CR (Corner Reflector) has a high RCS (Radar Cross Section) value, enough to have more than 30 dB SCR (Signal-to-Clutter Ratio).
- The position of all CRs is designed in order that all ST & HR beams can access at least one CR.
AOPOD (Atmosphere Occultation and Precision Orbit Determination)
AOPOD is a secondary payload consisting of IGOR, a spaceborne dual frequency GPS receiver and the LRRA (Laser Retro Reflector Array). The objective is to provide data for POD (Precision Orbit Determination) and GPS radio occultation measurements. KASI (Korea Astronomy and Space Science Institute) is in-charge of the development of the hardware and software for this system. 34) 35) 36)
The IGOR (Integrated GPS Occultation Receiver) of BRE (Broad Reach Engineering), Tempe, AZ, USA has been selected. The IGOR instrument, of BlackJack heritage, is customized to include a MIL-STD-1553B bus and two SSR (Solid State Recorders), each of 128 MByte. The IGOR instrument includes two RO antennas and two POD (Precision Orbit Determination) antennas. 37)
- IGOR instrument mass: 4.2 kg; size: 21.8 cm x 24.0 cm x 14.4 cm
- Peak power consumption: 25 W
- Tracking signals: L1 (1575.42 MHz) and L2 (1227.60 MHz)
- Tracking channels: 48 (4 antenna inputs)
- Sampling rate: 0.1 Hz and 50 Hz sampling; (0.1 Hz for POD support, 50 Hz for occultation science)
As shown in Figure 16, IGOR consists following parts: the RF receiving part to receive 4 RF signals, the digital part where the GPS signals are digitalized, the data storage device part consisting of a 128 MB SSR (Solid State Recorder), the 1553B interface part for the MIL-STD-1553B communication with the spacecraft, and the ground test interface part for the ground test and RS-422 communication.
In particular, all the parts except the RF receiving part are duplexed to secure the receiver stability. In the case of KOMPSAT-5, a total of 4 filter/preamp assemblies are installed in between the RF input port and the antenna in order to reduce the signal interference caused by the SAR signal. Two POD antennas and two occultation antennas are connected to the four RF input ports of the IGOR receiver.
The GPS signals received by the GPS antenna are stored in the SSR, the data storage device part, through the RF receiving part and the digital part. Since the capacity of the SSR data storage device is limited, the data is overwritten from the initial storage space of the SSR if the capacity of the received GPS data exceeds the SSR capacity. The current storage address of the raw data can be known through the telemetry. The GPS raw data stored in this way is transferred to the mass memory of KOMPSAT-5 and then transferred to and stored in the data storage server of the ground data center. The stored GPS raw data is transferred to the data processing server which processes the data to the RINEX (Receiver Independent Exchange) format, the standard GPS data format, and store it.
The GPS data processed in the ground data center can be used in various studies of the atmosphere and ionosphere including determination of satellite orbit and estimation of the temperature and pressure, vapor distribution and electron density in the atmosphere. The function of the IGOR is to provide the POD data for the determination of the precise satellite orbit and the GPS radio occultation data for scientific application research.
LRRA (Laser Retro Reflector Array)
The LRRA was developed at GFZ (GeoForschungsZentrum) Potsdam, Germany; it is being used for POD validation of KOMPSAT-5. The LRRA has four corner cube prisms mounted in a compact frame.
The KGS (KOMPSAT-5 Ground Segment) is developed by ETRI (Electronics and Telecommunications Research Institute) and operated by KARI. It consists of the following elements:
• MCE (Mission Control Element). MCE monitors and controls the satellite and provides mission planning. Mission control provides also operational orbit determination/prediction and the POD (Precise Orbit Determination) function.38)
• IRPE (Image Reception and Processing Element). 39)
• CVE (Calibration and Verification Element).
Overall, KGS provides the capability to receive, process, and distribute the KOMPSAT-5 payload data to satisfy the users of the KOMPSAT-5 mission.
The SAR data products of the mission will be globally distributed to the scientific and commercial user communities after completion of the commissioning phase (~ 6 months after launch). The products of the AOPOD will be used for weather forecasting by the national weather agency.
The ground segment for KOMPSAT-5 has a system ability to generate level products from raw data within an hour. In particular, this feature is important for event monitoring support.
HR (High Resolution)
In High Resolution Mode, the SSS (SAR Sensor Subsystem) shall provide Spotlight images with sliding spot extension of 5 km x 5 km swath width and a spatial resolution equal to 1 m x 1 m single look at 45º incidence angle
ST (Standard Mode)
In Standard Mode, the SSS shall provide Stripmap images with medium resolution, medium swath imaging, swath extension equal to 30 km and a spatial resolution of 3 m x 3 m single look at 45º incidence angle.
WS (Wide Swath)
In Wide Swath Mode, the SSS shall provide ScanSAR images with swath extension equal to 100 km and a spatial resolution of 20 m x 20 m at 45º incidence angle.
The KOMPSAT-5 SAR basic products are subdivided into four types:
1) L1A product: The level L1A product is a SCS (Single-look Complex Slant) product which is focused in slant range-azimuth projection that is the natural acquisition projection of the sensor. The primary purpose of L1A is to focus the image by compressing all of the energy that is backscattered from each illuminated target in the scene and acquired from the SAR antenna. Actually, the targets in an SAR image are acquired coherently along a certain time, so they distribute their energy in various image cells with many super positions of more targets in the same cell. This constitutes the main difficulty of SAR processing. The L1A also includes the determination of the Doppler Centroid, which is the centre frequency of the azimuth spectrum recorded by the SAR.
2) L1B product: The focused images obtained from the preceding L1A stage are in a slant range-azimuth plane. The application of the SAR images needs a more "user-friendly" geometry. Therefore, the L1B processing stage generates a detected ground multi-look product which is obtained by detecting, multi-looking, and projecting the SCS data onto a grid regular in ground.
3) L1C product: The L1C product is a geocoded ellipsoid corrected product which is obtained by projecting the L1A product onto a regular grid in a uniform pre-selected cartographic reference system (WGS84). For each sensor acquisition mode, the L1C contains the focused data, which is detected geo-coded on the reference ellipsoid and represented in a uniform preselected cartographic presentation.
4) L1D product: The L1D processing stage aims to generate a geocoded terrain corrected product which is fully calibrated through the use of a terrain model, then detected, geolocated on a DEM (Digital Elevation Model), and represented in a uniform pre-selected cartographic projection. The image scene is located and accurately (x, y, z) rectified onto a map projection through the use of ground control points and DEM. The L1D processing is performed on L1B data, with the use of the DEM for map projection.
MCE (Mission Control Element): The MCE system provides satellite control capabilities that allow the operators to carry out the KOMPSAT-5 mission with mission planning, command generation and transmission, telemetry processing and monitoring, flight dynamics support, and satellite static simulation. The system provides the primary interface to KOMPSAT-5 and the capabilities required to operate the KOMPSAT-5.
The MCE has the following key functions: satellite monitoring and control, mission planning and scheduling, flight dynamics, as well as S-band telemetry, tracking, and command.
FDS (Flight Dynamics Subsystem): The FDS is one of the core activities in the satellite mission operations for comprehensive orbital analysis and mission planning support as well as orbit data provision for image processing enhancement. For this, flight dynamics system provides the capability to analyze the satellite orbit and attitude in order to support mission operations. Flight dynamics team determines the satellite orbit by using satellite on-board GPS navigation solutions data as well as ground-based antenna tracking and ranging data. And, precise orbit determination using GPS raw data, i.e. pseudo-range and carrier phase measurement, is also carried out on a routine basis. The precise orbit ephemeris is distributed to the users for image processing. In addition, flight dynamics team generates orbit maneuver plan to maintain the satellite orbit within the pre-defined boundaries. Onboard fuel estimation is one of the tasks by flight dynamics team. Figure 4 represents the functional architecture and internal/external interface of KOMPSAT-5 flight dynamics subsystem in mission control element. 40)
IRPE (Image Reception and Processing Element): The IRPE provides the capability for receiving and storing KOMPSAT-5 SAR collected data; interfacing with the MCE for supporting image collection planning; generating standard and value-added SAR imagery products; and distributing imagery products to users. The IRPE also provides the X-band reception interface to satellite.
The IRPE consists of seven subsystems (Figure 20):
• Antenna and RF equipment
• DIS (Data Ingestion Subsystem)
• DAS (Data Acquisition Subsystem)
• ICPS (Image Collection Planning Subsystem)
• WMS (Workflow Management Subsystem)
• DPS (Data Processing Subsystem)
• UIS (User Interface Subsystem).
CVE (Calibration and Verification Element): The objective of CVE is the calibration of the COSI payload and maintaining its long-term system performance. Hence, the CVE's main goal is to model the relationship between geophysical parameters and measured backscattering coefficients.
The overall system calibration includes the following: internal/external calibration; compensation/correction of known system errors in amplitude and phase; georeferenced transformation of SAR image data to backscatter coefficients within an estimated error; development and procurement of calibration targets; and delivery of calibration information to be used during SAR product generation at the IRPE.
The CVE is comprised of the following elements:
• CVP (Calibration and Validation Processor)
• BCVP (Bus Calibration and Validation Processor)
• CVS ( Calibration and Validation System)
• ECS (External Calibration System).
The CVP calibrates the COSI payload in IOT (Initial Operational Test) phase and in the routine calibration phase. It also generates Antenna Lookup Table (LUT), calibration constant LUT, and azimuth cuts LUT from SAR Product, as well as L0 file received from IRPE. The CVP also evaluates the azimuth beam-pointing offset by estimating the Doppler center frequency; performing reports on calibration; and evaluating and reporting on image quality. The BCVP performs on-orbit calibration for spacecraft bus sensors and mechanical misalignment between the spacecraft bus reference axis and each sensor axis, and calibrates the antenna phase center of the dual frequency GPS receiver with respect to the KOMPSAT-5 satellite center of mass by comparison with precision orbit determination results using SLR. The CVS manages all data related to calibration activity and image quality evaluation, and is connected with the CVPs for the internal and external calibration through an ethernet environment. In addition, the CVS communicates with the IRPE and MCE in order to receive all data related to the calibration operation and to transfer all data required by the IRPE and MCE. The ECS is the facility comprising the calibration site, corner reflector, and extended target for supporting the operations foreseen for the calibration phase of payload IOT and routine SAR instrument calibration activities.
Some background on the KOMPSAT imagery distribution: In November 2012, Satrec Initiative (SI) of Daejeon, Korea announced an agreement with KARI (Korea Aerospace Research Institute) for "Worldwide Marketing and Sales Representative of KOMPSAT-2, -3, -3A and -5 image data." KARI assigned Satrec Initiative as the ‘worldwide exclusive representative' for KOMPSAT imagery sales. 41)
In response, the SI (Satrec Initiative Group) started a new company, SIIS (SI Imaging Services).The SIIS facilities are located at KARI. SIIS is the satellite imagery provider for Remote Sensing and Earth Observation. SIIS is the exclusive worldwide marketing and sales representative of the KOMPSAT series which is KOMPSAT-2, -3, -3A, -5 and DubaiSat-2. The DubaiSat-2 spacecraft was developed by SI in cooperation with MBRSC (Mohammed Bin Rashid Space Center), Dubai, UAE (United Arib Emirates), formerly EIAST (Emirates Institution for Advanced Science and Technology). On April 18, 2015, EIAST was officially renamed to MBRSC. 42)
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14) Yoola Hwang, Byoung-Sun Lee, Jaehoon Kim, Haedong Kim, Ok-Chul Jung , Dae-Won Chung, "Design and Implementation for KOMPSAT-5 Orbit Determination Operations," Proceedings of SpaceOps 2012, The 12th International Conference on Space Operations, Stockholm, Sweden, June 11-15, 2012, URL: http://www.spaceops2012.org/proceedings/documents/id1275514-Paper-004.pdf
15) Sang-Ryool Lee, Joo-Jin Lee, "The History of the Korea Multi-Purpose Satellite Program," Proceedings of the 60th IAC (International Astronautical Congress), Daejeon, Korea, Oct. 12-16, 2009, IAC-09.E4.3.3
16) "Ursa and SI Imaging Services Announce Further Collaboration On Satellite Analytics," Ursa, 29 January 2019, URL: https://www.ursaspace.com/single-post/2019/01/29/
17) Information provided by Sungdong Park, Chairman, Satrec Initiative Co., Ltd., Daejeon, Korea.
18) Information provided by Moon-gyu Kim, President & CEO of SIIS (SI Imaging Services), Daejeon, Korea
19) Information provided by Daewon Chung, PI (Principal Investigator)of KOMPSAT-5 and the head of the KARI Ground Systems Development Department, Daejeon, Korea.
20) Gunter Schreier, "Korean Earth Observation Data in Neustrelitz," DLR, Feb. 29, 2016, URL: http://www.dlr.de/eoc/en/desktopdefault.aspx/tabid-5258/19488_read-45645/
21) SIIS (SI Imaging Services) News, Feb. 1, 2016, URL: http://www.si-imaging.com/ds6_1_1.html?db=new_bbs&no=87&c=
view&page=1&SK=&SN=&kind3=&idx= [web source no longer available]
22) Information provided by Sungdong Park, CEO & Managing Director of SI (Satrec Initiative Co. Ltd.), Daejeon, Korea.
23) "SI News," Dec. 19, 2013, URL: http://kompsat.satreci.com/ds5_1_1.html?db=new_bbs&
24) "Satrec Initiative and KARI—Payload Performance Verification (Satellite—Imagery)," Satnews Daily, Dec. 19, 2013, URL: http://www.satnews.com/story.php?number=414093472#
25) Caleb Henry, "KARI Releases Kompsat 5 Images, Prepares for More EO Satellites," Satellite Today, Dec. 17, 2013, URL: http://www.satellitetoday.com/technology/2013/12/17/kari-releases
26) "Radio communication confirms successful launch of S. Korea's new satellite," Korea Herald, Aug. 23, 2013, URL: http://www.koreaherald.com/view.php?ud=20130823000083&mod=skb
27) "Telemetry data confirms launch of South Korean satellite," Space Travel, August 23, 2013, URL: http://www.space-travel.com/reports/Telemetry_data_
28) KOMPSAT-5 image data manual," SIIS (SI Imaging Services), URL: https://www.geosoluciones.cl/documentos/Kompsat-5/KOMPSAT_5_Image_Data_Manual(v1.0).pdf
30) Hoonyol Lee, "Radargrammetry of High Resolution Synthetic Aperture Radar Onboard KOMPSAT-5," Proceedings of IGARSS (IEEE International Geoscience and Remote Sensing Symposium) 2010, Honolulu, HI, USA, July 25-30, 2010
31) Duk-jin Kim, Wooil M. Moon, Ji-Hwan Hwang, Youn-soo Kim, "Application of KOMPSAT-5 for Emergent Oil Spill Monitoring," Proceedings of IGARSS (IEEE International Geoscience and Remote Sensing Symposium) 2010, Honolulu, HI, USA, July 25-30, 2010
32) JaeMin Shin, JinHee Kim, "Field Test of KOMPSAT-5 Calibration Equipment," Proceedings of IGARSS (IEEE International Geoscience and Remote Sensing Symposium) 2010, Honolulu, HI, USA, July 25-30, 2010
33) H. R. Jeong, D. H. Lee, T. B. Oh, C. H. Jung, H. S. Lim, "The KOMPSAT-5 Calibration Ground Equipment: Corner Reflector in Mongolia Site," Proceedings of the CEOS SAR Cal/Val Workshop, Zürich, Switzerland, Aug. 25-27, 2010
34) Sungki Cho, Wookyung Lee, Jong-K Chung, Jong-Uk Park, Jae-Cheol Yoon, Yongsik Chun, Sang-Ryool Lee, "Development Status of Radio Occultation Payload in KOMPSAT-5," Proceedings of the 4th Asian Space Conference & FormoSat-3/COSMIC International Workshop, Taipei, Taiwan, Oct. 1-3, 2008
35) Sungki Cho, Wookyung Lee, Mansoo Choi, Jong-Uk Park, Jae-Cheol Yoon, Jin-Hee Kim, Sang-Ryool Lee, "KOMPSAT-5 Radio Occultation Mission Status," FORMOSAT-3/COSMIC Data Users Workshop, Oct. 2009, Boulder, CO, USA, URL: http://www.cosmic.ucar.edu/oct2009workshop/prespublic/cho-29.pdf
36) Mansoo Choi, Woo-Kyoung Lee, Sungki Cho, Jong-Uk Park, "Operation of the Radio Occultation Mission in KOMPSAT-5," Journal of Astronomy and Space Sciences (JASS), Vol. 27, No 4, 2010, pp. 345-352
37) Sungki Cho, Mansoo Choi, Wookyung Lee, Jong-Uk Park, Jae-Cheol Yoon, Yongsik Chun, Sang-Ryool Lee, "Operation Plan of Radio Occultation Mission in KOMPSAT-5," GNSS RO Workshop, April. 2009, Pasadena, CA
38) Yoola Hwang, Byoung-Sun Lee, Young-Rok Kim, Kyoung-Min Roh, Ok-Chul Jung, Haedong Kim, "GPS-Based Orbit Determination for KOMPSAT-5 Satellite," ETRI (Electronics and Telecommunications Research Institute) Journal, Volume 33, Number 4, August 2011, pp. 487-496, URL: http://etrij.etri.re.kr/Cyber/servlet/GetFile?fileid=SPF-1312420426452
39) Myungjin Choi, Taeyoung Kim, Hee-Jin Bae, Yunyook Jang, Tae-Byeong Chae, Yong-Sik Chun, "The KOMPSAT-5 Image Reception and Processing Element," Proceedings of IGARSS (International Geoscience and Remote Sensing Symposium), Vancouver, Canada, July 24-29, 2011
40) Ok-Chul Jung, Su-Jin Choi, Jae-Cheol Yoon, Byoung-Sun Lee, Yoola Hwang, Dae-Won Chung, Eun-Kyu Kim, Hak-Jung Kim, "Flight Dynamics Operation for KOMPSAT-5 LEOP,"Proceedings of SpaceOps 2012, The 12th International Conference on Space Operations, Stockholm, Sweden, June 11-15, 2012, URL: http://arc.aiaa.org/doi/pdf/10.2514/6.2012-1259577
41) "Satrec Initiative Announces Agreement with Korea Aerospace Research Institute," SI, Nov. 15, 2012, URL: http://www.satreci.com/eng/ds1_1.html?tno=100&db=pr_board&no=22
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).