标题： 使用VLBA进行航天器导航的近实时天体测量：火星侦察轨道器和奥德赛的演示 显示英文标题

标题： Near real-time astrometry for spacecraft navigation with the VLBA: A demonstration with the Mars Reconnaissance Orbiter and Odyssey

摘要： 我们展示了使用甚长基线干涉阵列（VLBA）进行近实时航天器天文学的演示。我们检测了火星侦察轨道器和奥德赛轨道器的X波段下行信号，并通过互联网将数据传输到VLBA相关器以进行近实时相关处理。在天空平面上靠近火星的类星体被用作位置参考。在演示中，我们在观测开始后大约15分钟内获得了初始位置测量值。测量的位置与预测星历表之间的差异仅为几毫角秒，根据多次扫描的数据重复性优于0.3毫角秒。我们证明，即使移除一半的天线，仍然可以获得稳健且可重复的偏移量。这些观测结果证明了使用VLBA进行天文学测量的可行性，具有低延迟和亚毫角秒的重复性。 显示英文摘要

摘要： We present a demonstration of near real-time spacecraft astrometry with the VLBA. We detect the X-band downlink signal from Mars Reconnaissance Orbiter and Odyssey with the VLBA and transmit the data over the internet for correlation at the VLBA correlator in near real-time. Quasars near Mars in the plane of the sky are used as position references. In the demonstration we were able to obtain initial position measurements within about 15 minutes of the start of the observation. The measured positions differ from the projected ephemerides by a few milliarcseconds, and the repeatability of the measurement is better than 0.3 milliarcseconds as determined from measurements from multiple scans. We demonstrate that robust and repeatable offsets are obtained even when removing half of the antennas. These observations demonstrate the feasibility of astrometry with the VLBA with a low latency and sub-milliarcsecond repeatability.