To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can esti...To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can estimate directly the turbulent parameters of the scatters. We use this method to analyze the HF radar ACFs. A statistical study has been performed with the multi-frequency data, and shown that the statistical results are not the same in different frequency bands. We found that the influences of the limit radar time resolution and the received noise played the important roles in causing this inconsistency, both of them result in an additional expansion to the spectral width, and cause more Lorentzian behavior to ACFs; these two limitations affect the form of ACFs more seriously in the higher frequency band. We verified this by a simple simulation.展开更多
The ionospheric oblique backscattering sounding system can not only be used to detect the state of the ionosphere and the condition of high frequency channel in real time, but also be used for over-the-horizon soundin...The ionospheric oblique backscattering sounding system can not only be used to detect the state of the ionosphere and the condition of high frequency channel in real time, but also be used for over-the-horizon sounding. Therefore, it has a very high military and civil value. For the characteristics of ionospheric oblique backscattering sounding, such as long sounding distance, wake echo, strong background noise, slow moving target, etc., a hardware platform of ionospheric oblique backscattering sounding system is designed. This platform adopts the technology of software radio and is designed as a new kind of general purpose, modularized, software-based ionosonde that is based on the VXI （Versa module eurocard eXtensions for Instrumentation） bus. This hardware platform has been successfully used in actual ionospheric oblique backscattering sounding, and the experimental results demonstrate that this system can satisfy the requirements.展开更多
On the basis of the analysis of the system sounding principle, this paper introduced a new type of ionospheric oblique backscattering sound system, which is based on the pseudo- ran- dom noise phase modulated pulse co...On the basis of the analysis of the system sounding principle, this paper introduced a new type of ionospheric oblique backscattering sound system, which is based on the pseudo- ran- dom noise phase modulated pulse compression. According to the high requirements of real-time and a large amount of computation and echo characteristics, a high-speed real-time signal processing system was established and the design of system hardware and software was focused on. The sounding results indicate that the system is equipped to handle the data fast and has a high degree of software features. It is of great significance for the realization of fast, real-time ionospheric sounding means.展开更多
文摘To fit the autocorrelation functions (ACFs) of HF radar ionospheric backscattered signal to an analytical function, which is obtained theoretically by introducing a Lagrangian description of turbulent motion, can estimate directly the turbulent parameters of the scatters. We use this method to analyze the HF radar ACFs. A statistical study has been performed with the multi-frequency data, and shown that the statistical results are not the same in different frequency bands. We found that the influences of the limit radar time resolution and the received noise played the important roles in causing this inconsistency, both of them result in an additional expansion to the spectral width, and cause more Lorentzian behavior to ACFs; these two limitations affect the form of ACFs more seriously in the higher frequency band. We verified this by a simple simulation.
基金Supported by the National Natural Science Foundation of China (40474066)
文摘The ionospheric oblique backscattering sounding system can not only be used to detect the state of the ionosphere and the condition of high frequency channel in real time, but also be used for over-the-horizon sounding. Therefore, it has a very high military and civil value. For the characteristics of ionospheric oblique backscattering sounding, such as long sounding distance, wake echo, strong background noise, slow moving target, etc., a hardware platform of ionospheric oblique backscattering sounding system is designed. This platform adopts the technology of software radio and is designed as a new kind of general purpose, modularized, software-based ionosonde that is based on the VXI （Versa module eurocard eXtensions for Instrumentation） bus. This hardware platform has been successfully used in actual ionospheric oblique backscattering sounding, and the experimental results demonstrate that this system can satisfy the requirements.
基金Supported by the National Natural Science Foundation of China (40474066)
文摘On the basis of the analysis of the system sounding principle, this paper introduced a new type of ionospheric oblique backscattering sound system, which is based on the pseudo- ran- dom noise phase modulated pulse compression. According to the high requirements of real-time and a large amount of computation and echo characteristics, a high-speed real-time signal processing system was established and the design of system hardware and software was focused on. The sounding results indicate that the system is equipped to handle the data fast and has a high degree of software features. It is of great significance for the realization of fast, real-time ionospheric sounding means.
