Comparative analysis of reflection characteristics of lunar penetrating radar data using numerical simulations

Self-Organization Characteristics of Lunar Regolith Inferred by Yutu-2 Lunar Penetrating Radar

“…However, in the past, the lunar regolith has usually been assumed to be a uniform layered medium [4][5][6][7][8]. A series of recent studies have shown that the lunar regolith is essentially inhomogeneous [9][10][11][12][13][14][15][16] but the specific structural characteristics of the lunar regolith are still unclear.…”

“…Recently, several works have considered the heterogeneity [9][10][11][12][13][14][15] but do not take typical models into account (e.g., cracks and ejecta). Lv et al [16] constructed four typical models and performed numerical simulations using the time-domain finite-difference method, which can better present the wave propagation in the lunar regolith with strong heterogeneity. Some works noted the existence of weak heterogeneity of the lunar regolith [11,[33][34][35].…”

“…Some works noted the existence of weak heterogeneity of the lunar regolith [11,[33][34][35]. However, to date, no numerical simulation has been conducted specifically on the weak heterogeneity of the lunar regolith, probably due to three aspects: 1. lack of methods describing heterogeneous media; 2. technical difficulty in constructing random models; 3. excessive computational cost of numerical simulations [16] compared with traditional methods. In this study, we assumed that the weak heterogeneity of the lunar regolith obeys the self-organization model [36], which is basically a stochastic approach for dealing with scattering waves through randomly inhomogeneous structures and is well known in the seismology field; then, we used the finite-difference time-domain method [16] to carry out a series of numerical simulations using various models; next, we analyzed the influence of different parameters on the weak reflection characteristics; finally, we constrained the possible range of each controlling parameter through grid searching techniques by matching the numerical simulation results with the Yutu-2 LPR observations, in terms of waveforms, envelopes, and reflection patterns.…”

Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

“…We verify the effectiveness of the proposed method in a synthetic model using the finite difference time domain (FDTD) method [29], as shown in Figure 3a. The synthetic model consists of a heterogeneous background and several anomalous rocks with random relative permittivities less than 5.0 [24]. The dominant frequency of a Ricker wavelet is 500 MHz, the time windows and the sampling interval are 120 and 0.02 ns, respectively, and the trace interval is 0.005 m. Based on the picking positions in Figure 3d, we could scan the stacking velocity within the local scope of the simulation data.…”

“…The high-frequency electromagnetic wave will be reflected, diffracted, and refracted simultaneously when propagating the interface with discontinuous dielectric properties, such as boulders, voids, and soil inhomogeneities [24]. The LPR CH-2A and CH-2B data represent the common offset profiles, and the responses analyzed in semblance analysis are diffraction hyperbola instead of reflection hyperbola in the common midpoint data.…”