因為成本較低及發展時程較短，微小衛星逐漸在太空工程中佔有一席之地。目前微小衛星已被世界各國廣泛地運用於太空工程教育及地球觀測上。然而隨著愈來愈多的微小衛星進入軌道運行，不論是在空間上或是頻譜上都變得擁擠而產生衛星追蹤的問題，特別是在衛星剛被投射到軌道初期。有鑑於此，地面站性能之提升變得重要。本論文中以軟體無線電技術實現地面站接收機。此接收機具備靈活的頻率範圍及多頻道接收之能力。同時針對可能發生之同通道干擾，利用最大可能序列估測法進行單一天線干擾分離，提昇資料正確率。另一方面，世界各地遍布微小衛星地面站，因此可以透過網路連結各地之地面站進行共同接收。除了可以提高與衛星通聯之時間，增加接收資料量，並可利用投票機制降低資料錯誤率。結合軟體無線電與地面站網絡，可有效於降低資料錯誤率及增長資料接收時間兩種面向，提升地面站之性能，提供更好的衛星任務運作。

Because of lower cost and shorter developing duration, cubesats are widely used for space engineering education and earth observation. As many cubesats will operate in orbit, the closeness in spatial and spectral separation between different cubesats may render problems for ground stations in satellite tracking. We implement a ground station receiver with software defined radio (SDR) technique to solve these problems. The receiver is flexible in frequency range and with multi-channel receiving capability. Joint maximum likelihood sequence estimation algorithm is adopted to suppress co-channel interferences. Besides, we connect stations by Internet to provide larger contact probability and lower bit error rate. With these two approaches, ground stations can have better capability and improve mission performance.

[1] Akos, D.M. Stockmaster, M. Tsui, J.B.Y. Caschera, J., “Direct Bandpass Sampling of Multiple Distinct RF Signals,” IEEE Trans. Commun., Vol. 47, Issue 7, pp. 983-988, Jul 1999.
[2] Andreas Polydoros and Keith M. Chugg, “Per-Survivor Processing (PSP),” PIMRC 1997, Oulu, Finland, Sept. 1997.
[3] Charles R. Cahn. “Phase Tracking and Demodulation with Delay,” IEEE Trans. Inform. Theory, IT-20, pp 50-58, January 1974.
[4] Hamkins, J., “A Joint Viterbi Algorithm to Separate Cochannel FM Signals,” Proceedings of IEEE ICASSP '98, Vol. 6, pp 3297-3300, 12-15 May, 1998.
[5] Hoeher, P A; Badri-Hoeher, S; Xu, Wen; Krakowski, C, “Single-Antenna Co-Channel Interference Cancellation For TDMA Cellular Radio Systems”, IEEE Wireless Communications Magazine. Vol. 12, no. 2, pp. 30-37, Apr. 2005.
[6] J. C. Juang, C. T. Tsai, J. J. Miau, “A Software-Defined Radio Approach for the Implementation of Ground Station Receivers,” 6th IAA Symposium on Small Satellites for Earth Observation, IAA B6 0714P, Berlin, Germany, April 23 - 26, 2007.
[7] J. J. Miau, J. C. Juang, “A University Nano-Satellite Program: PACESAT,” 5th IAA Symposium on Small Satellites for Earth Observation,” IAA-B5-0 510P, Berlin, Germany, April 4 - 8, 2005.
[8] Jon Hamkins, “An Analytic Technique to Separate Cochannel FM Signals,” IEEE Trans. on Communications, Vol. 48, No. 4, April 2000.
[9] Jon Hamkins, Ed Satorius, Gent Paparisto and Andreas Polydoros, “A Comparative Study of Co-Channel Interference Suppression Techniques,” Proc. 5th IMSC, pp. 327-332, June 1997.
[10] Jung-Kuo Tu, Shi-Hua Wu, Chen-Chi Chu, “Platform for Attitude Control Experiment (PACE) An Experimental Three-Axis Stabilized CubeSat,” Proc. 18th AIAA/USU Conference on Small Satellites, SSC-VII, Utah State University, Logan Utah, USA, August 9-12, 2004.
[11] Kyle Leveque, “A Central Server Architecture for a Global Ground Station Network,” The 1st International Workshop on Ground Station Network, UNISEC, Tokyo, Japan, July 18 – 19, 2006.
[12] Marcin Stolarski, “The Use of Distributed Ground Station System for Very Low Power Communication,” The 1st International Workshop on Ground Station Network, UNISEC, Tokyo, Japan, July 18 – 19, 2006.
[13] Masaki Maeno, “XML and IP Based Ground Station System for Distributed Operations of Small Satellites,” The 1st International Workshop on Ground Station Network, UNISEC, Tokyo, Japan, July 18 – 19, 2006.
[14] Mitsuhito Komatsu, “A Report of GSN activities by Univ. of Tokyo ISSL -the efficient spacecraft operation system with domestic & international collaborators,” The 1st International Workshop on Ground Station Network, UNISEC, Tokyo, Japan, July 18 – 19, 2006.
[15] Mostafa et al., “Single Antenna Interference Cancellation (SAIC) for GSM Networks,” Proc. IEEE VTC, Orlando, FL, pp. 1089–93, October, 2003.
[16] P. A. Ranta, A. Hottinen, and Z.-C. Honkasalo, “Co-channel Interference Cancellation Receiver for TDMA Mobile Systems,” Proc. IEEE ICC ’95, Seattle, WA, pp. 17–21, June 1995.
[17] M. Patel, I. Darwazeh, and J. J. O’Reilly, “Bandpass Sampling for Software Radio Receivers, and the Effect of Oversampling on Aperture Jitter,” Proc. IEEE Vehicular Technology Conference, Vol. 4, pp 1901 – 1905, 2002.
[18] Riccardo Raheli, Andreas Polydoros and Ching-Kae Tzou, “Per-Survivor Processing: A General Approach to MLSE in Uncertain Environments,” IEEE Trans. on Communications, Vol. 43, No. 2/3/4, Feb/March/April 1995
[19] Rodney G. Vaughan, “The Theory of Bandpass Sampling,” IEEE Trans. on Signal Processing, Vol. 39, No. 9, September 1991.
[20] W. Etten, “Maximum Likelihood Receiver for Multiple Channel Transmission Systems,” IEEE Trans. Commun., Vol. 24, No. 2, pp. 276–83, Feb. 1976.
[21] Yasuhisa Oda, “A Report on Students' Ground Station Network Project in Japan,” The 1st International Workshop on Ground Station Network, UNISEC, Tokyo, Japan, July 18 – 19, 2006.
[22] Andrea Goldsmith, Wireless Communications, Cambridge University Press, 2005.
[23] David M. Pozar, Microwave Engineering, Third Edition, John Wiley & Sons, 2004.
[24] Jeffery H. Reed, Software Radio: A Modern Approach to Radio Engineering, Prentice Hall PTR, 2002.
[25] John G. Proakis, Digital Communication, 4th Edition, McGraw-Hill, 2001.
[26] Leland B. Jackson, Digital Filters and Signal Processing, 2nd Edition, Kluwer Academic Publishers, 1989.
[27] M.C. Jeruchim, P. Balaban, and K.S. Shanmugan, Simulation of Communication Systems, Kluwer Academic/Plenum Publishers, New York, 2000.
[28] Peter B. Kenington, RF and Baseband Techniques for Software Defined Radio, Boston, Artech House, 2005
[29] PXI-3710 User's Guide, ADLINK Technology Inc, 2004.
[30] PXI-9820 User's Guide, ADLINK Technology Inc, 2004.
[31] R. E. Collin, Foundations for Microwave Engineering, Second Edition, McGraw-Hill, 1992.
[32] Stavroulakis, Peter, Interference Analysis and Reduction for Wireless Systems, Boston, MA, Artech House, 2003
[33] 陳克任, 現代類比暨數位通訊 數位篇, 儒林圖書公司。
[34] 陳克任, 現代類比暨數位通訊 類比篇, 儒林圖書公司。
[35] http://cubesat.calpoly.edu/
[36] http://lss.mes.titech.ac.jp/ssp/cubesat/
[37] http://polysat.calpoly.edu/CP4.php
[38] http://www.arrl.org/FandES/field/regulations/bandplan.html
[39] http://www.celestrak.com/columns/v04n03/
[40] http://www.nspo.gov.tw/2005c/projects/projectothers/YamSat.htm
[41] http://www.space.t.u-tokyo.ac.jp/cubesat/
[42] http://www.sstl.co.uk/
[43] http://www.terasoft.com.tw/news/data/news031202.asp