Study On Ionospheric Phase Perturbation Correction Algorithm For HF Radar

Compared with traditional radar,HF radar has many outstanding advantages,such as beyond-line-of-sight detection and low altitude detection,anti-stealth and so on.When the high frequency radar in sky wave mode enjoys the convenience brought by the ionosphere reflection and refraction,the echo signal of the radar will also be affected by the ionosphere,and the phenomena such as phase disturbance,multipath effect and multimode propagation will appear.Therefore,it is very important to study ionospheric phase perturbation correction of sky wave mode high frequency radar.In this paper,the ionospheric phase perturbation correction algorithm in sky wave mode high frequency radar is studied.Whole content includes the radar target signal and first-order sea clutter signal modeling,and in view of the present theory more and more widely applied three kinds of typical algorithm analyzed the principle and algorithm simulation,finally to put forward in re cent years based on three phase function of ionospheric phase perturbation correction methods are studied,studied the method under the condition of the continuous phase perturbation performance.Finally,the paper uses two indicators to compare and analyze the four algorithms mentioned above,and compares the advantages and disadvantages of the four algorithms,so as to provide a reference for the selection of algorithms.The specific work of this paper can be divided into three parts:First,the structure of the ionosphere is analyzed,the reason of the phase disturbance of the ionosphere is analyzed from the physical mechanism,and the basic principle of signal processing of sky wave over-the-horizon radar is given.The pollution mechanism of ionosphere to radar echo is analyzed,and the ionosphere phase perturbation correction algorithm is classified.Secondly,the target echo signal is modeled and simulated according to the radar target characteristics and sea clutter characteristics,and then the phase perturbation function is corrected on this basis.In the numerous phase perturbation of the correction algorithm of the more classic three algorithms: the maximum entropy spectrum estimation method,the phase gradient method and the piecewise polynomial phase method,respectively,on the principle of the three algorithms are introduced,and the simulation of the phase perturbation is slow and fast change in both cases algorithm correction effect,summarized according to the characteristics of three kinds of algorithms.Thirdly,a phase perturbation correction algorithm based on cubic phase function proposed in recent years is introduced and analyzed by simulation.Under both constant amplitude phase perturbation and non-constant amplitude phase perturbation,the algorithm can sharpen the broadened sea clutter spectrum peaks and recover the submerged target signals well.By using two measurement indexes--root mean square error(RMSE)and maximum puller frequency shift,the four algorithms simulated in this paper are compared horizontally,and their advantages and disadvantages are analyzed.