Research On Flying Target RCS Fusionestimation Of Bistatic HFSWR

High frequency surface wave radar(HFSWR) works in the high frequency band of 3~30MHz, which is a complex electromagnetic environment and exits lots of external interference. As a typical burst interference, lightning interference frequently occurs in the summer by the sea, seriously affects the detection performance of high frequency surface wave radar. Radar cross section(RCS) is a physical description of the ability of the target scattering to the radar’s electromagnetic waves, and has a direct relationship with the radar echo.This paper introduces the research status, research background an d significance of the subject firstly. And then presents the theoretical basis of high frequency RCS estimation, such as FMICW signal, high-frequency surface wave radar equation, high frequency wave propagation and attenuation mathematical model and lighti ng interference features. Secondly, combined with the characterisitic anglysis of flying target in high-frequency band, two parameters: frequency, target attitude angle, which impact the RCS estimation are purposed. Two different estimation methods are put forward corresponding to the different parameters. And simulation is done to demonstrate its effectiveness. It is difficult for HFSWR to utilize vertically polarized wave to configure narrow beam in elevation direction, which results in the disability to obtain the height information. And then, aiming at this problem, different height/RCS estimation models are proposed for bistatic radar at high altitude region and low altitude region according to the different characteristics of wave propagation and attenuation at different regions.In the high-altitude area, the change in height direction impact slightly on wave propagation attenuation. Based on this situation, combined with the target slant range of type T/R-R bistatic radar, a height/RCS estimation model is formed in high spatial. At the same time, taking bistatic radar’s positioning accuracy into consideration, the model selects a combination of three high accuracy observation vectors in four and echo intensity the T/R station and R station obtained as the observable of extended Kalman filter(EKF) to estimate the height information and radar target RCS. Finally, data fusion by weighted fusion algorithm is made for the estimation results of the T/R station and R station.At low altitude area, propagation attenuation is sensitive to changes in height direction. For the purpose of solving the multiple solutions problem, the highly-interested spatial is divided into several sub-space. Propagation attenuation in each sub-space can be considered as a fixed value, and separated EKFs to estimate height/RCS are allocated in each sub-space. Then weigh the separated estimated results according to the probability of every sub-space which the target may be in. Aiming to avoid the influence of RCS fluctuation on hight/RCS estimation, AR model based on the fluctuation part of RCS is introduced. Thus the estimation accuracy can be enhanced.