VEX-V-VRA-1-2-3-EXT2-0484

Data Set Overview The Venus Express (VEX) Radio Science (VeRa) Data Archive is a timeordered collection of raw and partially processed data collected during the Venus Express Mission. This is a Occultation measurement covering the time 20110705T02:05:42.050 to 20110705T03:38:55.949. This data set contains archival raw, partially processed, and ancillary/supporting radio science data acquired during the Routine Operations phase of the Venus Express (VEX) mission using ground facilities of the European Space Agency (ESA) and/or the NASA Deep Space Network (DSN). VeRa radio occultation observations start shortly before the occultation ingress, when the VEX spacecraft moves behind the planetary disk as seen from the Earth and stop shortly after the occultation egress, when the probe emerges from behind the planet. VeRa occultation data usually cover three recording phases: the occultation ingress (1), the time when the spacecraft is occulted by the planet (2) and the occultation egress (3). The different observation phases can be distinguished by regarding the AGC data, which records the strength of the received signal. In phase (1) and (3) the AGC level is high compared to phase (2). In Phase (2) still a signal may be received at the groundstation due to the strong bending of the radio waves in the dense atmosphere. The strength of the signal is significantly reduced and weakens further the deeper the radio waves penetrate the atmosphere until the groundstation may be unable to lock. Therefore, the beginning of phase (2) is recognized at first order by a sharp drop of the AGC down to 95 dB and lower and ends with a sharp rise in the AGC data back to the former AGC level. For the derivation of higher science products it is recommended to divide the level 2 data into an ingress and an egress part and to process these data seperatetly. This data set was collected during the VEX science subphase 34 (P truncated!, Please se [truncated!, Please see actual data for full text]

数据集概览：金星快车（VEX）无线电科学（VeRa）数据存档系对金星快车任务期间收集的原始及部分处理数据的按时间顺序整理。该数据集涵盖了从20110705T02:05:42.050至20110705T03:38:55.949的时间段内的掩星测量。该数据集包含了在金星快车（VEX）任务的常规操作阶段，利用欧洲空间局（ESA）和/或美国宇航局深空网络（DSN）地面设施获取的存档原始、部分处理及辅助/支持性无线电科学数据。VeRa无线电掩星观测始于掩星入射前，即金星快车探测器从地球视角进入行星盘之后，并终止于掩星出射后，即探测器从行星背后浮现出来。VeRa掩星数据通常涵盖三个记录阶段：掩星入射阶段（1）、探测器被行星掩蔽的时间阶段（2）以及掩星出射阶段（3）。不同的观测阶段可通过观察自动增益控制（AGC）数据来区分，AGC数据记录接收信号的强度。在阶段（1）和（3）中，AGC的级别相较于阶段（2）较高。在阶段（2）中，尽管由于大气层中无线电波的强烈弯曲，地面站仍可能接收到信号，但信号的强度显著减弱，并且随着无线电波深入大气层而进一步减弱，直至地面站可能无法锁定。因此，阶段（2）的开始可以通过AGC水平首次急剧下降至95分贝以下来识别，并随着AGC数据的急剧上升回到之前的AGC水平而结束。为了推导更高层次的科学产品，建议将第2级数据分为入射和出射两部分，并分别对这些数据进行处理。本数据集是在VEX科学子阶段34（请见[截断，请参阅实际数据以获取完整文本]）期间收集的。