Lunar Penetrating Radar（LPR） has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within...Lunar Penetrating Radar（LPR） has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise.First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method（CCM） is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m（ε_r = 6.6） and from 13.0 m to 17.5 m（ε_r = 2.3）, respectively.展开更多
The permittivity of lunar regolith is crucial for further processing and interpretation of radar data.The conventional hyperbolic fitting method ignores the antenna height and spacing and has a significant error at a ...The permittivity of lunar regolith is crucial for further processing and interpretation of radar data.The conventional hyperbolic fitting method ignores the antenna height and spacing and has a significant error at a shallow depth.For the new method that considers the layout of the antenna,the influencing factors have not been studied.In this paper,we studied the influence of the position of the hyperbola peak and time zero on the new method for permittivity derivation.The simulation results show that when the input errors of time zero,abscissa and ordinate of the hyperbolic peak are±2 ns,±0.02 m and±0.2 ns respectively,the average errors of the calculated results by points within 1 m from the hyperbolic peak are 10.0%,16.7%and 38.2%,respectively.To improve the accuracy,we used the average results by points that are horizontally more than 1 m away from the hyperbola peak.Hence,we calculated the permittivity of the lunar regolith by the new method based on Lunar Penetrating Radar data.The average permittivity of the lunar regolith is estimated to be 3.3±1.2.展开更多
Lunar Penetrating Radar （LPR） based on the time domain Ultra-Wideband （UWB） technique onboard China＇s Chang＇e-3 （CE-3） rover, has the goal of inves- tigating the lunar subsurface structure and detecting the de...Lunar Penetrating Radar （LPR） based on the time domain Ultra-Wideband （UWB） technique onboard China＇s Chang＇e-3 （CE-3） rover, has the goal of inves- tigating the lunar subsurface structure and detecting the depth of lunar regolith. An inhomogeneous multi-layer microwave transfer inverse-model is established. The di- electric constant of the lunar regolith, the velocity of propagation, the reflection, re- fraction and transmission at interfaces, and the resolution are discussed. The model is further used to numerically simulate and analyze temporal variations in the echo obtained from the LPR attached on CE-3＇s rover, to reveal the location and structure of lunar regolith. The thickness of the lunar regolith is calculated by a comparison be- tween the simulated radar B-scan images based on the model and the detected result taken from the CE-3 lunar mission. The potential scientific return from LPR echoes taken from the landing region is also discussed.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 41403054)
文摘Lunar Penetrating Radar（LPR） has successfully been used to acquire a large amount of scientific data during its in-situ detection. The analysis of penetrating depth can help to determine whether the target is within the effective detection range and contribute to distinguishing useful echoes from noise.First, this study introduces two traditional methods, both based on a radar transmission equation, to calculate the penetrating depth. The only difference between the two methods is that the first method adopts system calibration parameters given in the calibration report and the second one uses high-voltage-off radar data. However, some prior knowledge and assumptions are needed in the radar equation and the accuracy of assumptions will directly influence the final results. Therefore, a new method termed the Correlation Coefficient Method（CCM） is provided in this study, which is only based on radar data without any a priori assumptions. The CCM can obtain the penetrating depth according to the different correlation between reflected echoes and noise. To be exact, there is a strong correlation in the useful reflected echoes and a random correlation in the noise between adjacent data traces. In addition, this method can acquire a variable penetrating depth along the profile of the rover, but only one single depth value can be obtained from traditional methods. Through a simulation, the CCM has been verified as an effective method to obtain penetration depth. The comparisons and analysis of the calculation results of these three methods are also implemented in this study. Finally, results show that the ultimate penetrating depth of Channel 1 and the estimated penetrating depth of Channel 2 range from 136.9 m to 165.5 m（ε_r = 6.6） and from 13.0 m to 17.5 m（ε_r = 2.3）, respectively.
基金funded by the National Natural Science Foundation of China(NSFC,Grant No.12073048)supported by the Key Research Program,Chinese Academy of Sciences,Grant No.ZDBS-SSW-JS007。
文摘The permittivity of lunar regolith is crucial for further processing and interpretation of radar data.The conventional hyperbolic fitting method ignores the antenna height and spacing and has a significant error at a shallow depth.For the new method that considers the layout of the antenna,the influencing factors have not been studied.In this paper,we studied the influence of the position of the hyperbola peak and time zero on the new method for permittivity derivation.The simulation results show that when the input errors of time zero,abscissa and ordinate of the hyperbolic peak are±2 ns,±0.02 m and±0.2 ns respectively,the average errors of the calculated results by points within 1 m from the hyperbolic peak are 10.0%,16.7%and 38.2%,respectively.To improve the accuracy,we used the average results by points that are horizontally more than 1 m away from the hyperbola peak.Hence,we calculated the permittivity of the lunar regolith by the new method based on Lunar Penetrating Radar data.The average permittivity of the lunar regolith is estimated to be 3.3±1.2.
基金Supported by the National Natural Science Foundation of China
文摘Lunar Penetrating Radar （LPR） based on the time domain Ultra-Wideband （UWB） technique onboard China＇s Chang＇e-3 （CE-3） rover, has the goal of inves- tigating the lunar subsurface structure and detecting the depth of lunar regolith. An inhomogeneous multi-layer microwave transfer inverse-model is established. The di- electric constant of the lunar regolith, the velocity of propagation, the reflection, re- fraction and transmission at interfaces, and the resolution are discussed. The model is further used to numerically simulate and analyze temporal variations in the echo obtained from the LPR attached on CE-3＇s rover, to reveal the location and structure of lunar regolith. The thickness of the lunar regolith is calculated by a comparison be- tween the simulated radar B-scan images based on the model and the detected result taken from the CE-3 lunar mission. The potential scientific return from LPR echoes taken from the landing region is also discussed.
