Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predict...Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predicted resources of 480 million GWh.On the basis of the 1:200,000 gravity and 1:10 aeromagnetic data and constrained by the well-explored Fushan Depression and Baocheng Rock Mass,we conducted a sys-tematic study of hot dry rocks and evaluated the development potential of the geothermal resources of the medium-depth and deep hot dry rocks in Hainan Island for thefirst time.The island is structurally active,with extensive granites,strong volcanic and earthquake activities,and many hot springs,indicating that the geothermal geological conditions are favorable.There are two types of hot dry rocks,sedimentary basin type and uplifted mountain type,on the island.The sedimentary basin-type hot dry rocks are mainly found in the north of the island and have an area of 2657 km^(2),an average depth of 2480 m,and an average heat reservoir temperature of 230℃ at 6000 m depth.Uplifted mountain-type hot dry rocks with a total area of 13,000 km^(2) mainly occur in Danzhou in the north of the island and Baocheng in the south.The heat reservoirs of these rocks are Yanshanian intrusive plutons and the average temperature is 236℃ at 6000 m depth.Nine favorable hot dry rock targets are identified,of whichfive are sedimentary basin types and four are uplifted mountain types.The Fushan and Eman depressions in north Hainan Island and the Baocheng Rock Mass in the south of the island are the preferred exploration targets.展开更多
With the new system radar put into practical use, the characteristics of complex radar signals are changing and developing. The traditional analysis method of one-dimensional transformation domain is no longer applica...With the new system radar put into practical use, the characteristics of complex radar signals are changing and developing. The traditional analysis method of one-dimensional transformation domain is no longer applicable to the modern radar signal processing, and it is necessary to seek new methods in the two-dimensional transformation domain. The time-frequency analysis method is the most widely used method in the two-dimensional transformation domain. In this paper, two typical time-frequency analysis methods of short-time Fourier transform and Wigner-Ville distribution are studied by analyzing the time-frequency transform of typical radar reconnaissance linear frequency modulation signal, aiming at the problem of low accuracy and sen-sitivity to the signal noise of common methods, the improved wavelet transform algorithm was proposed.展开更多
In order to solve the recognition of polyphase code radar signal, this paper gives two methods based on Frank code, i.e. the high-order spectrum recognition method and the fractional Fourier transform (FRFT) method, b...In order to solve the recognition of polyphase code radar signal, this paper gives two methods based on Frank code, i.e. the high-order spectrum recognition method and the fractional Fourier transform (FRFT) method, by analyzing the micro characteristics of polyphase code signals in time and frequency domain respectively. And a recognition algorithm based on Wigner-Hough transform (WHT) is developed in this paper. We verify the validity of each method by computer simulation and give relative merits and demerits. A set of results demonstrate that the algorithm based on Wigner-Hough transform has better recognition performance in low signal-to-noise (SNR) than others.展开更多
基金Research on Exploration and Evaluation of hot dry rock Resources and Target Area Preference(No.2023-HNKT-001)This article is sponsored by the New Energy Technology Development and Application Research Project No.2022DJ5503.
文摘Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates.Surface features and actual drilling have confirmed that there are rich geothermal resources in the area,with predicted resources of 480 million GWh.On the basis of the 1:200,000 gravity and 1:10 aeromagnetic data and constrained by the well-explored Fushan Depression and Baocheng Rock Mass,we conducted a sys-tematic study of hot dry rocks and evaluated the development potential of the geothermal resources of the medium-depth and deep hot dry rocks in Hainan Island for thefirst time.The island is structurally active,with extensive granites,strong volcanic and earthquake activities,and many hot springs,indicating that the geothermal geological conditions are favorable.There are two types of hot dry rocks,sedimentary basin type and uplifted mountain type,on the island.The sedimentary basin-type hot dry rocks are mainly found in the north of the island and have an area of 2657 km^(2),an average depth of 2480 m,and an average heat reservoir temperature of 230℃ at 6000 m depth.Uplifted mountain-type hot dry rocks with a total area of 13,000 km^(2) mainly occur in Danzhou in the north of the island and Baocheng in the south.The heat reservoirs of these rocks are Yanshanian intrusive plutons and the average temperature is 236℃ at 6000 m depth.Nine favorable hot dry rock targets are identified,of whichfive are sedimentary basin types and four are uplifted mountain types.The Fushan and Eman depressions in north Hainan Island and the Baocheng Rock Mass in the south of the island are the preferred exploration targets.
文摘With the new system radar put into practical use, the characteristics of complex radar signals are changing and developing. The traditional analysis method of one-dimensional transformation domain is no longer applicable to the modern radar signal processing, and it is necessary to seek new methods in the two-dimensional transformation domain. The time-frequency analysis method is the most widely used method in the two-dimensional transformation domain. In this paper, two typical time-frequency analysis methods of short-time Fourier transform and Wigner-Ville distribution are studied by analyzing the time-frequency transform of typical radar reconnaissance linear frequency modulation signal, aiming at the problem of low accuracy and sen-sitivity to the signal noise of common methods, the improved wavelet transform algorithm was proposed.
文摘In order to solve the recognition of polyphase code radar signal, this paper gives two methods based on Frank code, i.e. the high-order spectrum recognition method and the fractional Fourier transform (FRFT) method, by analyzing the micro characteristics of polyphase code signals in time and frequency domain respectively. And a recognition algorithm based on Wigner-Hough transform (WHT) is developed in this paper. We verify the validity of each method by computer simulation and give relative merits and demerits. A set of results demonstrate that the algorithm based on Wigner-Hough transform has better recognition performance in low signal-to-noise (SNR) than others.
