MEX-M-MARSIS-3-RDR-SS-EXT2

Data Set Overview MARSIS Level 2 data products consist of Level 1b data that have been uncompressed, corrected for Automated Gain Control, aligned to a reference altitude and, except for data acquired using the SS2 mode, rangeprocessed after correcting for the distortion of the transmitted signal caused by the ionosphere. Echoes collected in the acquisition (ACQ) phase, having a much smaller bandwidth, do not have a vertical resolution sufficient for scientific analysis, and thus are not used in generating Reduced Data Records. Geometric information needed to locate observations in space and time is also provided in the Data Set. Parameters MARSIS data are the result of the processing of groups of echoes called frames. A frame is produced by the coherent summation of many tens of echoes. Each frame is recorded as a time series of complex signal samples. Scientific data in a frame are complemented by a set of engineering data, produced by the instrument and recording parameter values used in pulse transmission, echo reception and onboard processing, and by geometric information needed to locate observations in space and time. Processing Level 2 processing of subsurface sounding data consists of several steps, needed to convert the instrument telemetry into a collection of radar echoes that can be used for geological analysis and interpretation of the Martian subsurface. These are: Data decompression: 8bit spectrum samples are converted back to 4byte real numbers. AGC compensation: the gain scaling factor, applied during Automated Gain Compensation, is applied to the data. Receiving time compensation: echoes are shifted in time to refer them to a common altitude above the Martian ellipsoid. Range compression: the received signal is convolved with the transmitted signal to increase range resolution and signaltonoise ratio. Ionosphere distortion correction: an algorithm to c truncated!, Please see actual data for full [truncated!, Please see actual data for full text]

{'Data_Set_Overview': '数据集概览', 'MARSIS_Level_2_data_products': 'MARSIS二级数据产品', 'consist_of': '由以下内容组成', 'Level_1b_data': '一级B数据', 'uncompressed': '未经压缩', 'corrected_for': '经校正', 'Automated_Gain_Control': '自动增益控制', 'aligned_to': '对齐至', 'reference_altitude': '参考高度', 'rangeprocessed': '经距离处理', 'distortion_of_the_transmitted_signal': '传输信号的畸变', 'ionosphere': '电离层', 'Echoes_collected_in_the_acquisition': '采集阶段收集到的回波', 'ACQ': 'ACQ（采集）', 'bandwidth': '带宽', 'vertical_resolution': '垂直分辨率', 'Reduced_Data_Records': '缩减数据记录', 'Geometric_information': '几何信息', 'Parameters': '参数', 'MARSIS_data': 'MARSIS数据', 'processing': '处理', 'frames': '帧', 'complex_signal_samples': '复信号样本', 'Scientific_data': '科学数据', 'engineering_data': '工程数据', 'instrument': '仪器', 'pulse_transmission': '脉冲传输', 'echo_reception': '回波接收', 'onboard_processing': '机载处理', 'Processing': '处理', 'subsurface_sounding_data': '地下探测数据', 'instrument_telemetry': '仪器遥测', 'radar_echoes': '雷达回波', 'geological_analysis': '地质分析', 'interpretation': '解释', 'Data_decompression': '数据解压缩', '8bit_spectrum_samples': '8位频谱样本', '4byte_real_numbers': '4字节实数', 'AGC_compensation': 'AGC补偿', 'Receiving_time_compensation': '接收时间补偿', 'Range_compression': '距离压缩', 'Ionosphere_distortion_correction': '电离层畸变校正'}