中文摘要：

天体测量法是探测系外行星一种有效的手段，具有其他探测方法所不具备的独特优势，如可以探测到行星的3维轨道参数及确定行星的质量等，这些将为现有的行星样本提供重要补充．高精度的空间天体测量卫星Gaia（Global Astrometric Interferometer for Astrophysics）在2013年成功发射升空，可以预期未来基于其探测数据、将可能发现大量的长周期类木行星．针对dCentauriA、HD62509和GJ876系统，根据Gaia单次天体测量精度生成对应的仿真数据，使用Lomb—Scargle周期谱分析行星轨道周期信号，并采用Markov Chain Monte Carl of MCMC）算法对行星系统进行轨道反演，得到的结果与行星的初始参数相吻合．

英文摘要：

Astrometry is an effective method to detect exoplanets. It has many advantages that other detection methods do not bear, such as providing three dimensional planetary orbit and determining the planetary mass. Astrometry will enrich the sample of exoplanets. As the high-precision astrometric satellite Gaia （Global Astrometry interferometer for Astrophysics） was launched in 2013, there will be abundant long-period Jupiter-size planets to be discovered by Gaia. In this paper, we specify the α Centauri A, HD 62509, and GJ 876 systems, and generate the synthetic astrometric data with the single astrometric precision of Gaia. Then we use the Lomb-Scargle periodogram to analyse the signature of planets and the Markov Chain Monte Carlo （MCMC） algorithm to fit the orbit of planets. The simulation results are well coincide with the initial solutions.