Satrec Initiative Co.

Daejeon, South Korea

Satrec Initiative Co.

Daejeon, South Korea
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Kim E.D.,Satrec Initiative Co. | Lee H.,Satrec Initiative Co. | Kim E.-E.,Satrec Initiative Co. | Kim B.,Satrec Initiative Co. | Park S.,Satrec Initiative Co.
Proceedings of the International Astronautical Congress, IAC | Year: 2016

The advancement of small satellite and launcher technologies attracted unprecedented interest (and investment) in the so-called NewSpace industry recently. Ignited by Google's Terra Bella (former Skybox Imaging), there have been numerous Earth observation constellation projects announced in the past few years. As opposed to traditional spatial resolution-centric Earth observation missions, these small satellite constellation missions focus on better temporal resolution applications. SpaceEye-X was developed as Satrec Initiative's (SI) next generation high performance Earth observation satellite. With 0.5 m or better GSD and higher imaging capacity, it was designed to give WorldView-class spatial resolution and wide swath for a small satellite. It was also designed to be compact enough to be launched simultaneously to form a constellation. With the improved agility, more advanced imaging modes are doable, and the constellation can monitor various shaped borderlines or coastline with higher temporal resolution. Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved.

Kim S.I.,Satrec Initiative Inc | Hwang D.-H.,Chungnam National University
Journal of Institute of Control, Robotics and Systems | Year: 2017

In this paper, a new dark current detection method for the star tracker is proposed to improve the accuracy of satellite attitudes. In the proposed method, the dark current is detected by adding values of the edge area in the image measurements of the region of interest in each frame to the detected dark current. The detected dark current is compensated in the image. The proposed method is implemented in an FPGA (Field Programmable Gate Array) and a real-time experiment is performed. The experimental results show that the centroiding error standard deviations of the identified stars are significantly reduced when dark currents are compensated by the proposed method. © ICROS 2017.

Ha J.S.,Agency for Defense Development | Park G.C.,Agency for Defense Development | Lee J.S.,Agency for Defense Development | Cho B.L.,Agency for Defense Development | And 3 more authors.
2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011 | Year: 2011

A forward imaging radar (FIR) detecting obstacles from the ground needs 2-D imaging methods for an unmanned ground vehicle (UGV). Although a back-projection method is the most suitable algorithm, its processing time is too slow to make 2D image in real time. To make a fast imaging algorithm such as frequency domain algorithm, the proposed algorithm uses the scaling factor of that algorithm. This paper proposes a fast data processing algorithm using the scaling factor, based on mono-static SAR system. © 2011 KIEES.

Kim D.H.,Satrec Initiative Co. | Kim T.H.,Satrec Initiative Co. | Choi W.H.,Satrec Initiative Co. | Seon S.G.,Agency for Defense Development | And 2 more authors.
2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011 | Year: 2011

The system that this paper deals about is one stationary bistatic SAR using ultra wide band chirp pulse. Because of the large bandwidth, the echo signal is mixed with the transmitted signal. Then the mixed signal is saved as a raw data. The system has an intrinsic difficulty in processing the raw data due to the long pulse bandwidth. So, it is very complicated to process the data in Doppler domain. This paper proposes an alternative way of processing the data acquired by this kind of SAR system. © 2011 KIEES.

Choi R.K.Y.,National Institute of Meteorological science | Ha J.-C.,National Institute of Meteorological science | Cho Y.-J.,National Institute of Meteorological science | Lim E.,National Institute of Meteorological science | And 5 more authors.
14th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2016 - Proceedings | Year: 2016

A set of compact microwave radiometers are under development for tropospheric sounding and imaging, as a part of the Compact High Altitude Imager and Sounding Radiometer (CHAISR) that operates in lower stratosphere. It aims to observe vertical temperature profiles and column-averaged water vapour for entire troposphere where most weather system takes place. Given total weight (4 kg) and power (50 W) constraints for the CHAISR are not the only challenges. The CHAISR requires nominal operation in thermal range between-75 and +43 °C up to 50 hPa. Along with optical cameras and in situ sensors in the CHASIR, microwave radiometers are to fit in 130 mm diameter and 290 mm length with total weight less than 1.5 kg for conical scan unit. Maximum power consumption of less than 15 W does not allow conventional internal blackbody calibration facility onboard, and alternative methods has been developed. Frequency ranges of three radiometer bands are ∼20, ∼40, and ∼55 GHz, with 16 total channels. This MMIC based compact radiometers use quasi-correlation design for continuous observation for both reference and scene. Numerical simulation of the radiometer design shows less than 1 °K of RMSE is expected. Manufacture of the CHAISR is expect to be first quarter of 2017 and test flight is planned in summer of the same year. © 2016 IEEE.

Yoon H.,Satrec Initiative Co. | Paek S.W.,Massachusetts Institute of Technology | Lim Y.,Korea Advanced Institute of Science and Technology | Lee B.-H.,Satrec Initiative Co. | Lee H.,Satrec Initiative Co.
IEEE Transactions on Aerospace and Electronic Systems | Year: 2013

We propose a new star pattern identification algorithm using the vector pattern matching technique on the celestial sphere. The proposed algorithm provides more robust identification performance in cases where the captured star images are biased from the onboard catalog star image positions. The technique is based on the approach of maximizing the target score function, which is formed by the correlation between the original and the reference star patterns on the celestial sphere. © 1965-2011 IEEE.

Shin D.,Satrec Initiative Co. | Lee S.,Satrec Initiative Co.
International Journal of Remote Sensing | Year: 2015

This article describes a technique which estimates line-of-sight (LOS) parameters of each CCD array in a high-resolution electro-optical sensor on board a satellite using statistical information which is extracted automatically from a large number of real images acquired after launch. First, the focal length of panchromatic (PAN) CCD arrays is estimated by using thousands of ground control points (GCPs) converted to raw image space. Second, a model is introduced for deriving LOS parameters for multispectral (MS) CCD arrays in one focal plane assembly (FPA) such as the focal lengths and the first/last detector cell positions from automatically matched band-to-band (B2B) tie-points. Finally, the LOS parameters of all arrays in one FPA are updated using automatically matched tie-points in the overlap zone (OZ) in order to represent the geometrical relationship between the CCD arrays with the same spectral band in two FPAs. The proposed technique was applied to the calibration of a ground segment image processor for a currently operating high-resolution imaging satellite during its initial commissioning phase. This article describes the accuracy and robustness of the LOS parameters estimated by the proposed technique by using more than one hundred images covering full geographical locations and off-nadir tilt angle ranges. © 2015, © 2015 Taylor & Francis.

Luengo M.,UrtheCast | Mazzoleni A.,UrtheCast | Bravo F.A.,UrtheCast | Pisabarro P.,UrtheCast | And 4 more authors.
14th International Conference on Space Operations, 2016 | Year: 2016

The DEIMOS-2 mission is fully owned and operated by Deimos Imaging, a Spanish private company subsidiary of UrtheCast Corp. (Canada). The DEIMOS-2 satellite was successfully launched on June 19th, 2014 from the Yasny Launch Base (Russia). Beyond any positive expectation, the first images were acquired and produced within just 12 hours from separation and LEOP was completed without any blocking issues after a week. Commissioning activities and Calibration and Validation (CAL/VAL) phases started immediately, only one week after launch. During the IOC, the operations team wrote its own operational procedures, tools and contingency protocols. Finally, DEIMOS-2 entered in Full Operational Capability (FOC) in May 2015, time in which the operations team was fully integrated with the other company departments. As a result, Deimos Imaging is capable of providing the customer with the complete (end-to-end) service, from the first initial contact with the customer until the final product delivery, chain which includes an initial feasibility analysis, planning of the acquisitions, commanding to the satellite, downloading the images, production and delivery. This paper addresses the operational experience of the Deimos Imaging Operations team, and in particular, the evolution of the activities during the early life of the DEIMOS-2 satellite. Current satellite nominal operations, maintenance activities and satellite health analysis are also described. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Kim D.-H.,Satrec Initiative Co. | Yoon J.-C.,Korea Aerospace Research Institute | Shin J.-M.,Korea Aerospace Research Institute | Kim M.-G.,Satrec Initiative Co.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2010

In KOMPSAT-5 program, Korea Aerospace Research Institute has made SAR imaging chain analysis tool to evaluate imaging system of KOMPSAT-5. The tool consists of a simulator and a processor. The simulator simulates observation of a scene by the operational mode of KOMPSAT-5 and generates SAR raw data. The processor generates an image of the scene. This paper is about the second part of processing the simulated raw data that is acquired by the step steering sliding spotlight mode of KOMPSAT-5. For this observation mode, dechirp on receive is operated in receiving the echoes. So, extended frequency scaling algorithm is used to process the raw data in order to directly handle the dechirped data [2]. This paper mainly contributes for the accuracy of effective velocity. The effective velocity criterions for range and azimuth processing allows that the processor uses only one scene center effective velocity in range processing and several ones in azimuth processing. In this paper, a method to increase the accuracy of calculation of effective velocity is also proposed. Simulation result shows that the proposed method is valid. © 2010 IEEE.

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