Sang-Soon Yong

Korea Geostationary Ocean Color Imager (KGOCI)

Korea Aerospace Research Institute (KARI) has a plan to launch COMS for consistent monitoring of the Korean Peninsula. Korea Geostationary Ocean Color Imager (KGOCI) is one of the main payloads of COMS which will provide a monitoring of ocean-colour around the Korean Peninsula from geostationary platforms. Ocean color observation from geostationary platform is required to remedy the coverage constraints imposed by polar orbiting platforms. In this paper the main characteristics of KGOCI are described. It will provide the measurement data of 6 visible channels and 2 near-infrared channels (400 nm-900 nm). The high radiometric sensitivity is essential of ocean color sensor because of the weak water leaving radiance. The integration time and aperture diameter required to achieve the SNR specification of KGOCI are analyzed.

Implementation of DDS chirp signal generator on FPGA

Synthetic aperture radar (SAR) is an active sensor that is widely used such as military purpose, land observation, and etc. The main characteristics of SAR system are as follow. First, as SAR uses microwave, it can be operated regardless of the weather and day-night conditions. SAR system uses the signal called chirp to acquire large bandwidth then it provides high-resolution images. The conventional analog type chirp generator of SAR system occupies large amount of space and weight. To implement chirp generator in small satellites, implementation of chirp generator on FPGA will be discussed in this paper.

The Analysis on the relation between the Compression Method and the Performance Enhancement of MSC(Multi-Spectral Camera) Image data

Multi-Spectral Camera(MSC) is a main payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/ storage. The compression method on KOMPSAT-2 MSC was selected and used to match EOS input rate and PDTS output data rate on MSC image data chain. At once the MSC performance was carefully handled to minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP and Cal./Val.(Calibration and Validation) phase. In this paper, on-orbit image data chain in MSC and image data processing on KGS including general MSC description is briefly described. The influences on image performance between on-board compression algorithms and between performance restoration methods in ground station are analyzed, and the relation between both methods is to be analyzed and discussed.

The design of MSC (multi-spectral camera) system operation

Multi-spectral camera (MSC) is a payload on the KOMPSAT-2 satellite to perform the Earth remote sensing. The instrument images the Earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The installment is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and onboard image data compression/storage. The MSC instrument has one (1) channel for panchromatic imaging and four (4) channels for multi-spectral imaging covering the spectral range from 450 nm to 900 nm using TDI CCD Focal Plane Array (FPA). In this work, the architecture and function of MSC hardware including electrical interface and the operation concept which have been established based on the mission requirements are described. The design and the preparation of MSC system operation are analyzed and discussed.

Development of the new generation of geostationary ocean color imager

The Geostationary Ocean Color Imager II (GOCI-II) is the next generation of GOCI, which is one of the main payloads of the Korean COMS satellite. GOCI was the first ocean color sensor in the world operating on the geostationary orbit.

Current Status and Future Prospects of Satellite Payloads Technology

Satellite payload can be classified as electro-optical payload, SAR, microwave radiometer, communication payload, navigation payload and so on in accordance with the mission objective. The technology of satellite payload was tried to be obtained through development of KOMPSAT series, COMS and STSAT in Korea. In this paper, the required technology for the development and world market trend of satellite payload were studied and described. Since KOMPSAT program has been started in 1994, technology status and future prospects of satellite payload in Korea are studied and analyzed.

Development of chirp signal generator for micro satellite on-board synthetic aperture radar

For L-band micro satellite on board SAR system, the suitable chirp signal generator for this system is needed. In this paper, the chirp signal generator with direct digital synthesizer (DDS) is considered instead of the memory map based chirp signal generator. Furthermore, to overcome the limitation of clock frequency of the space component, parallelized DDS (PDDS) method is used. However, phase error is one of the problem to implement DDS chirp signal generator. Therefore, we propose a novel method to compensate this error. As a result, the output performance of the signal is enhanced using the proposed phase error compensation method.

An experimental study on verification of the compact airborne imaging spectrometer system

The Compact Airborne Imaging Spectrometer System (CAISS) was designed and developed as the airborne hyperspectral imaging system. The mission of the CAISS is to provide full contiguous spectral information with high spatial resolution for advanced applications in the field of remote sensing. The CAISS has an ability to control the spectral and spatial configuration of the imaging instruments. In order to understand the mechanism of imaging spectrometer system and its characteristics, the several verification tests with the CAISS were conducted in the laboratory. Especially, the verification of camera system was performed with the integrating sphere and spectral lamps. In order to verify the spectral characteristics, four spectral binning (x1, x2, x4, and x8) were measured using each of the spectral lamps and the position of the peaks was compared to the reference data sheet of each spectral lamps. For all measurements, it was found that the spectral deviation was lower than the Full Width Half Maximum (FWHM) of the system for each of the spectral binning. Also several interface verification tests between the CAISS and the airplane were conducted on the ground. This paper presents the preliminary results of verification test in the camera system level and interface test with airplane on the ground.

The initial checkout of MSC (multi-spectral camera) system

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/storage. KOMPSAT-2 was launched on July 28 2006 and stared early operation including Initial Activation and Checkout(IAC). During IAC phase, MSC was checked and tested by prepared procedure. In this paper, the preparation, the sequence and the procedure of MSC initial activation checkout including SOH (State Of Health) are described. The activities including the checkout results during IAC as parts of Launch & Early Operation Period (LEOP) are discussed and analyzed.