Accurate relative permittivity is essential to the further analysis of lunar regolith. The traditional hyperbola fitting method for the relative permittivity estimation using the lunar penetrating radar generally ignored the effect of the position and geometry of antennas. This paper proposed a new approach considering the antenna mounting height and spacing in more detail. The proposed method is verified by numerical simulations of the regolith models. Hence the relative permittivity of the lunar regolith is calculated using the latest high-frequency radar image obtained by the Yutu-2 rover within the first 24 lunar days. The simulation results show that the relative permittivity is underestimated when derived by the traditional method, especially at the shallow depth. The proposed method has improved the accuracy of the estimated lunar regolith relative permittivity at a depth of 0–3 m, 3–6 m, and 6–10 m by 35%, 14%, and 9%, respectively. The thickness of the lunar regolith at the Chang’E 4 landing site is reappraised to be 11.1 m, which improved by ~8% compared with previous studies.

The MOSIR (Mars Orbiter Subsurface Investigation Radar) is one of the scientific payloads carried by the Tianwen-1 orbiter. MOSIR conducted a ground experiment in the desert near Dengkou County, northern China, before the launch of the Tianwen-1 satellite. The MOSIR prototype was suspended from a hot air balloon and flew over a flat region at an altitude of 2500–3300 m. This experiment aimed to verify the system performance and data processing. The data collected in subsurface sounding mode is performed range compression, and the altitude measurement data removes invalid data. After processing, the altitude measurement results of two operating modes are analyzed and compared with that of the Global Position System (GPS), which verifies the accuracy of the altitude measurement.

This paper deals with the investigation of the Martian subsurface in the Utopia Planitia region using the Zhurong’s ground-penetrating radar. The low-frequency data recorded along the overall path followed by the rover are processed thanks to a customized signal processing pipeline aiming on one side to minimize the artifacts in the radargrams and, on the other one, to obtain images of the subsoil that aid the following analysis and interpretation stage. The images reveal a three-layer structure beneath the landing area up to the depth of ~40 m. The general scattering characteristics indicate the presence of 5~8 m regolith, 2~3 m fine materials, and 15~30 m embedded with blocks generating a significant electromagnetic scattering. The existence of an upwards decrease in grain size is resulted from long-term weathering and repeated impacts, or the occurrence of flood events. The radargrams depict a distinctive local enhancement of the scattering at the end of the rover route from Sol 292 to Sol 325. Analysis of the layout of barchan dunes and the distribution of craters suggests that the resurfacing activity is the result of a complex combination of tectonic activities and impact events.

The radar surface echo can be separated into coherent and incoherent components by statistical approaches, and the coherent component can be described by a backscattering model related to the RMS height. According to backscattering models for fractal surfaces, the coherent power in decibels decreases with RMS height on a scale independent of the wavelength at a rate depending on the Hurst exponent and the roughness scale. We extract the coherent power in four research areas by fitting the amplitude distribution of the Martian surface echoes recorded by the SHARAD radar, and compare the coherent power with the RMS height derived from pulse width of the MOLA laser altimeter. Scatter plots of squared MOLA‐derived RMS height‐coherent power are drawn to estimate the rates of coherent power fall‐off by linear fitting, and the fitting power fall‐off rates are compared to the Hurst exponents derived from digital terrain models in those areas. The fitting rates decrease with the Hurst exponent, similar to the theoretical rates. However, the fitting rates decrease with the Hurst exponent more sharply than the theoretical prediction. We explain the mismatch with a linear assumption between different roughness parameters, which helps to estimate the Hurst exponent, and a significant discrepancy between the wavelength and the roughness scale might influence the estimation results due to the scaling dependence of the Hurst exponent. This paper offers an opportunity to learn about the Hurst exponent at a tens‐of‐meter scale.

The dielectric properties of lunar regolith are critical in constraining radar wave propagation and guiding geological interpretation in planetary subsurface exploration. While previous assessments at the Chang’E-5 (CE-5) landing site relied on orbital remote sensing, this study introduces a novel in situ permittivity inversion framework tailored for the Lunar Regolith Penetrating Radar (LRPR) system, providing point-scale measurements that complement previous orbital assessments. This approach overcomes the limitations of conventional hyperbolic diffraction analysis commonly applied to Chang’E-3/4 radar data. By integrating the LRPR’s geometric configuration with electromagnetic wave propagation theory, we developed a depth-resolved inversion methodology based on iterative coherence optimization of radar echoes. The retrieved results indicate an average relative permittivity of 4.04±1.51 (1σ) within the upper 2.5 m of the regolith. This methodology enhances in situ dielectric characterization for future lunar missions and reveals stratified permittivity zones and an immature regolith structure, providing direct evidence for the Eratosthenian-aged geological context of the CE-5 sampling site.