| Spaceborne detection equipment has the ability to detect the distribution of space plasma density and related parameters,and has been researched and developed by major institutions.Research hotspots also tend to design wireless remote sensing detection system with light weight,low power and long detection distance,however,the limited transmitting power will affect the detection distance of radar system.In order to achieve long-distance detection of targets and radar systems with higher sub-parts,this paper designs the waveform of a satellite-borne sweep stepper radar according to the basic situation of the satellite-based radar detection environment and the parameter range of the satellite-based detection system,so that the radar system can achieve long-range and high-resolution detection and real-time detection of space plasma distribution and parameters such as distance,Doppler,and dialback angle of arrival,etc.The main research content can be summarized as follows.First,based on the theory of ambiguity function,swept-frequency stepping radar,and pulse compression,combined with the detection environment of spaceborne radar,the advantages of frequency stepping signal are introduced,and the application of frequency stepping signal in spaceborne radar system is proposed.It is verified that the frequency step signal can also have the advantages of the distance itself in the spaceborne radar system: to achieve high-resolution,long-distance detection.Then,on the basis of coding fuzzy function theory,several traditional codings are discussed and analyzed,focusing on modeling and simulating the fuzzy function of frequency step signal of Barker code and long pulse coding,and analyzing the advantages and disadvantages,and summarizes the two effect of using this kind of code in spaceborne radar.Second,according to the spaceborne radar detection environment and the spaceborne coding principle,the filter suitable for the spaceborne VLF swept frequency stepping radar is selected.according to the simulation results of the spaceborne swept-frequency stepping radar coding,based on the design principle of the matched filter based on Barker code and long pulse coding,and combined with the spaceborne radar detection environment,the Kaiser-Bessel filter was selected.In the parameter setting range of the system,the proposed Kaiser-Bessel filter is added to the noise 10 times larger than the signal source,and the module built on the Java platform is used for debugging.Finally,after filtering by the Kaiser-Bessel filter,a relatively good signal-to-noise ratio is obtained,which restores the original transmitted signal well.It also verifies that the Kaiser-Bessel filter can be applied to the spaceborne swept-frequency stepping very low frequency radar.in the system. |
