Subsurface Structure Detection Of Mars Based On Detection Radar

Mars is the most similar planet to Earth in the solar system.The subsurface layer of Mars has become a hot spot in the study of Mars because it contains information about water ice and geological evolution.Researchers in China and abroad have been using data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding(MARSIS)and Shallow Subsurface Radar(SHARAD),The subsurface of the north and south polar regions of Mars and some special topographic regions have been studied by using the forward and inverse method of permittivity and corresponding results have been obtained.In summary,the existing research results all rely on spaceborne detection radar,and the northern hemisphere of Mars is less studied.With the return of radar data carried by the Tianwen-1 mission,especially that of the Zhurong rover,a new opportunity has been provided for the exploration of the subsurface surface of Mars.Based on the Penetrating data of shallow surface Radar and Mars Rover Penetrating Radar(Ro Pe R),this study selected part of trace data of the Utopian plain region in the northern hemisphere of Mars.The permittivity of subsurface media in the research area was calculated.The following are recognized:(1)The ionosphere of Mars will cause attenuation and distortion of radar signals.The contrast method(CM)can reduce the influence of the ionosphere on the phase shift of radar signals.The Chapman model and Gamma model can effectively compensate the distortion of signals propagating in the ionosphere.Thus avoiding the ionospheric distortion and distortion of data.For radar data containing noise,a relatively optimized denoising filter is determined by comparing the denoising methods and results in spatial domain and frequency domain.Log-Gabor function is used instead of Gabor function to process noisy signals and gain effective reflected signals to generate radar images with obviously strong reflected signals,and to identify and remove clutter from the ground in SHARAD Radargram after denoising.It provides favorable conditions for the extraction of radar pulse reflection power at different underground layers.(2)Through the detection radar data preprocessing,the echo power of different Martian subsurface surfaces is extracted,and the strong reflected signals of different surfaces are used to estimate the dielectric constant and layer thickness information of each layer in the SHARAD trajectory region.The corresponding material composition can be judged by the estimated dielectric constant information,and the structure information of the Martian subsurface surface can be inferred.This paper adopts the method based on Continuous Wavelet Transform(CWT)to detect the peak value.By detecting the peak value of each column in the enhanced radar graph,it solves the problem of detecting the linear feature from the radar graph.Thus,the subsurface reflection information is extracted from SHARAD Radargram,and the dielectric constant information of each layer of the subsurface layer of Mars is estimated by using the linear relationship between the reflection power and the tangent value of dielectric loss.The layered structure of the subsurface layer of Mars is determined by using the existing dielectric information of materials and research basis.(3)The study of the subsurface layer of Mars has been relying on MARSIS and SHARAD data.With the return of the radar data of the Tianwan-1 probe,the study of the subsurface structure of Mars by using the data of the Tianwan-1 probe has become a current research hotspot.In this paper,several SHARAD tracks in the Utopia region of Mars and low-frequency data of the sub-surface detection radar of the Zhurong rover before August 17,2021 are selected.Through data processing,the layered dielectric constant information of the Mars sub-surface in the study area is calculated,and the sub-surface structure information of the trajectory region corresponding to SHARAD and Ro Pe R is obtained.The results show that there is no water ice in the upper subsurface area of the study area.