The Radar Imager for Mars’ Subsurface Experiment (RIMFAX) is a Ground Penetrating Radar on the Mars 2020 mission’s Perseverance rover, which is planned to land near a deltaic landform in Jezero crater. RIMFAX will add a new dimension to rover investigations of Mars by providing the capability to image the shallow subsurface beneath the rover. The principal goals of the RIMFAX investigation are to image subsurface structure, and to provide information regarding subsurface composition. Data provided by RIMFAX will aid Perseverance’s mission to explore the ancient habitability of its field area and to select a set of promising geologic samples for analysis, caching, and eventual return to Earth. RIMFAX is a Frequency Modulated Continuous Wave (FMCW) radar, which transmits a signal swept through a range of frequencies, rather than a single wide-band pulse. The operating frequency range of 150–1200 MHz covers the typical frequencies of GPR used in geology. In general, the full bandwidth (with effective center frequency of 675 MHz) will be used for shallow imaging down to several meters, and a reduced bandwidth of the lower frequencies (center frequency 375 MHz) will be used for imaging deeper structures. The majority of data will be collected at regular distance intervals whenever the rover is driving, in each of the deep, shallow, and surface modes. Stationary measurements with extended integration times will improve depth range and SNR at select locations. The RIMFAX instrument consists of an electronic unit housed inside the rover body and an antenna mounted externally at the rear of the rover. Several instrument prototypes have been field tested in different geological settings, including glaciers, permafrost sediments, bioherme mound structures in limestone, and sedimentary features in sand dunes. Numerical modelling has provided a first assessment of RIMFAX’s imaging potential using parameters simulated for the Jezero crater landing site.

中文翻译：

---

用于火星地下实验的雷达成像仪—RIMFAX

火星地下实验雷达成像仪 (RIMFAX) 是火星 2020 任务的恒心漫游车上的探地雷达，计划降落在 Jezero 陨石坑的三角洲地形附近。RIMFAX 将通过提供对火星车下方浅层地下进行成像的能力，为火星车的调查增添新的维度。RIMFAX 调查的主要目标是对地下结构进行成像，并提供有关地下成分的信息。RIMFAX 提供的数据将有助于 Perseverance 探索其野外地区古老的宜居性，并选择一组有希望的地质样本进行分析、缓存并最终返回地球。RIMFAX 是一种调频连续波 (FMCW) 雷达，它发射信号扫过一系列频率，而不是单个宽带脉冲。150–1200 MHz 的工作频率范围涵盖了地质中使用的 GPR 的典型频率。通常，全带宽（有效中心频率为 675 MHz）将用于低至几米的浅层成像，而较低频率（中心频率 375 MHz）的减少带宽将用于更深结构的成像。每当漫游车在深、浅和水面模式中的每一种模式下行驶时，大部分数据将以固定的距离间隔收集。具有扩展积分时间的固定测量将改善选定位置的深度范围和 SNR。RIMFAX 仪器由一个安装在漫游车体内的电子单元和一个安装在漫游车后部外部的天线组成。几个仪器原型已经在不同的地质环境中进行了现场测试，包括冰川、永久冻土沉积物、石灰岩中的生物群丘结构和沙丘中的沉积特征。数值模拟使用为 Jezero 陨石坑着陆点模拟的参数提供了对 RIMFAX 成像潜力的首次评估。