Measured Data Analysis And The Technology Of Performance Improvement In High-Frequency Radar

High-frequency radar has an advantage in the over-the-horizon detection,and it plays an important role in the ocean state(ocean current,wind speed,etc.)detection.However,when the high-frequency radar applies to the target detection,the sea clutter will cover up the target which lead to false positive and false negative rate increase,and make the target detection and tracking difficult.In addition,the ionospheric phase contamination of high frequency sky wave radar will make the echo signal spectral shift,broaden,resulting in the target and the clutter spectrum aliasing.In this paper,the correlation simulation of sea clutter suppression algorithm and the ionospheric phase decontamination algorithm is carried out,and those algorithms are validated by using the measured data.The main work is summarized as follows:Firstly,the processing method of linear frequency modulated interruption continuous wave signal is introduced.The signal processing process is deduced in detail,and the relevant simulation is carried out.The causes of the range ambiguity are analyzed,and the method of solving the range ambiguity is given.The results show the effectiveness of the proposed method and finally give the results obtained by using this method to process the measured data.Secondly,the formation mechanism of sea clutter is introduced briefly,and the sea clutter suppression method is introduced and the relevant simulation analysis is made.And then these kinds of sea clutter suppression algorithm are used to process the measured data.According to the results,the comparison analysis of these kinds of sea clutter suppression algorithm is carried out.It can be seen from the results that it is very important to choose a right number when apply to the clutter cancellation to suppress the sea clutter.A big number will cause the target to be eliminated,and a little number will cause the clutter to be ineffectively suppressed.Lastly,the formation mechanism of the ionospheric phase contamination is introduced,and then the ionospheric phase decontamination algorithms are introduced,and the relevant simulation analysis is carried out.Then those algorithms are used to process the measured data.The correlation correction algorithm is compared according to the processing results.The results show that the selection of the number of segments need to be taken into account when using the short-term segmentation method.The excessive number of segments will lead to a larger frequency estimation error for each segment.If the number of segments is too small,the estimated pollution will be too linear which will make the final pollution correction effect bad.In addition,it can be seen that the phase gradient method is much better than the short-term segmentation method when the pollution level is small.