VEX-V-VRA-1-2-3-EXT1-0196

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 20080728T04:31:47.050 to 20080728T05:46:49.949. 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 is a radio occultation measurement of the Venusian atmospher truncated!, Please se [truncated!, Please see actual data for full text]

数据集概览：金星快车号（VEX）无线电科学（VeRa）数据档案是一组按时间顺序排列的原始和部分处理数据，这些数据是在金星快车号任务期间收集的。该数据集涵盖了一次掩星测量，时间范围为20080728T04:31:47.050至20080728T05:46:49.949。此数据集包括存档的原始、部分处理和辅助/支持性无线电科学数据，这些数据是在金星快车号（VEX）任务的常规操作阶段，利用欧洲航天局（ESA）和/或美国国家航空航天局深空网络（NASA DSN）的地面设施获取的。VeRa无线电掩星观测始于掩星入射前不久，此时从地球视角看，VEX航天器移动至行星盘后，并在掩星出射后不久结束，此时探测器从行星后方浮现。VeRa掩星数据通常涵盖三个记录阶段：掩星入射阶段（1）、航天器被行星掩蔽的时间阶段（2）以及掩星出射阶段（3）。不同的观测阶段可以通过观察自动增益控制（AGC）数据来区分，该数据记录了接收到的信号强度。在阶段（1）和（3）中，AGC水平相较于阶段（2）较高。在阶段（2）中，由于密集大气层中无线电波的强烈弯曲，地面站可能仍然能够接收到信号。信号强度显著减弱，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水平急剧下降至95分贝以下并继续下降来初步识别，而结束则伴随着AGC数据急剧上升恢复至之前的AGC水平。为了推导出更高层次的科学产品，建议将第二级数据分为入射部分和出射部分，并分别对这些数据进行处理。这是一个截断的金星大气层无线电掩星测量，请参阅[截断，请参阅实际数据以获取全文]。