Korea Astronomy and Space Science Institute (KASI) launched the development project of two satellite laser ranging (SLR) systems in early 2008 after the government fund approval of the SLR systems in 2007. One mobile SLR system and one permanent SLR station will be developed with the completion of the project. The main objectives of these systems will be focused on the Space Geodetic researches. A system requirement review was held in the second half of the same year. Through the following system design review meeting and other design reviews, many unsolved technical and engineering issues would be discussed and resolved. However, the design of the mobile SLR system is a corner stone of whole project. The noticeable characteristics of Korea's first SLR system are 1) use of light weight main mirror, 2) design of compact optical assembly, 3) use of KHz laser pulse, 4) use of commercial laser generator, 5) remote operation capability, 6) automatic tracking, 7) state of art operation system, etc. In this paper, the major user requirement and pre-defined specification are presented and discussed.

In the basic GMSK, the modulated signals are generated by the preprocessing of NRZ pulse trains with the gaussian low pass filter. In this paper, we proposed the GMSK modulation system with the delta pulse trains.The proposed system constructed with the gaussian pulse generator triggered by the bipolar delta pulse, the differentiator between +Tb/2 and -Tb/2, and then a matched filter for frequency-modulation function. The spectrum of proposed system was found to be smaller than about 35[%] at 40[dB] attenuated bandwidth, and the center spectrum to be lower than the basic GMSK with zero-crossing property.

. 이러한 변조에 대한 대 부분의 복조 방식은 NRZ 펄스열을 복원하는 시스 템 구조 [2,3] , 차분 검출 방법 [4] , 시이퀀스 검출 방법 등이 연구되었다 [5,6] .본 논문에서는 델타 펄스열로 발생시킨 가우시안 펄스에 의한 GMSK 변조 시스템의 복조 방법에 대 하여 연구하였다. 이 변조 방식은 기존 GMSK에서 오차함수를 제거하고 차분기를 사용하여 중심 주파 수에서의 전력 밀도를 감소시키고 점유 스펙트럼을 협소하게 한 변조 방식이다 [7] . 기존의 GMSK는 NRZ 펄스열에 대한 복조에 맞 추어져 있기 때문에 델타 펄스열에 대한 복조는 기 존의 방식들에 대한 분석과 연구를 통해 새롭게 설 계할 필요가 있다.

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