Radar Target Rcs Near And Far Field Transformation

Stealth and anti-stealth technology is the major field in modern warfare, it was been the focus of national military research.RCS is the most important parameter in the study on the stealth and anti-stealth technology; it is also one of the most important parameters on evaluating the scattering characteristics. Researching on the measurement of RCS is with great significance. According to the different measurements, RCS measurement can be divided into far-field measurement, near-field measurement and compact range measurement. Far-field measurement is conducted outdoor. Although the RCS of a target can be directly read out, it is difficult to satisfy the condition (the objective under the measurement is in the far-field region of the antenna of the radar).Near-field measurement and compact range measurement carry out in microwave anechoic chamber satisfy the condition easily. Compared to the compact range measurement, near field measurement is more precise, and the cost has also been reduced. In this thesis, the near-field measurement is studied carefully, and a method to obtain the total RCS though the measurement of near-field of a target was studied.In order to obtain RCS of the target, the target is equivalent to scattering center,and the scattering centers were distributed on the line at the centre of the target. Neglecting of the interaction between scattering centers and the radar, neglecting the interaction between scattering centers and the test environment, we studied the estimated the total RCS of the target by the near-field measurement data. The process of the algorithm of the estimation was studied based on the radar echo signals. The characteristics of the weighting function were abstracted from the simulation results in several cases such as the single-station address, single-station side-view, symmetrical bistatic stations and symmetrical bistatic stations. The simulation was studied especially on the effect of different parameters on the amplitude and phase of weighting function. And the exact value of the weighting function was decided with the calibration. Different sizes of metal balls were exploited to find the value of weighting function with the comparison of experimental data and the theoretical value of RCS. The RCS of target was then calculated from the near-field measurement data with proposed algorithm. At last the calculated RCS was compared with the theoretical value to verify the algorithm is feasibility.In the end of the thesis, conclusion and future work were given.