Research On Key Technologies Of Impulse Radar

In this dissertation, an impulse radar prototype system is developed. The principle concepts of beam synthesis, beam scanning of impulse signal, as well as the performance of target detection are experimentally verified. Moreover, the basic theories of beam synthesis efficiency, beam scanning control, data processing method of array impulse radar are studied.According to the existed research results of transmission characteristics of impulse signal and radiation characteristics of the time domain antenna, we proposed the point source approximate analytical model in which the antenna is regarded as a point source, and can show the characteristics of the given unit antenna radiation to fill the blank of analytical analysis to influential factors of antenna array electromagnetic radiation beam. On the basis, we give analytic formula and numerical analysis method to calculate the influence of array beam width, array synthesis efficiency, beam direction control, target tracking and locating method, trigger and amplitude jitter of impulse sources, etc. The numerical simulation software is also developed based on the point source approximation model. Both analytical and numerical results are in good agreement with experiment results.We settle the problem of effective extraction of object in time-domain radar by proposing an impulse signal data processing method, including time calibration, amplitude normalized, time-varying amplification. Based on this method, clear images of static and dynamic target can be obtained, which can be used as a reference method for signal data processing method.To construct the impulse radar prototype system, we first develop the impulse signal source based on the solid state devices and Marx bank circuit, and optimize the slot antenna design, as well as the receiving subsystem with equivalent time sampling circuit. The impulse radar system is then assembled and tested based. The prototype is with array size of 2×2 m2 and array elements of 3×3. The experiment results of the prototype show that, the peak radiation power of 80 kW, detection distance of 2 km, distance resolution of 0.3-0.5 m,angle resolution of 3°, repetition rate of 5 kHz, beam scan range of ±45°. All of the parameters of the prototype have reached the expectation.The experiments are carried on in the impulse radar prototype system to confirm the achievement of beam synthesis and beam scanning technologies. The time domain beam forming efficiency of 3×3 array exceeds 80% in the far field zone(about 2km), the scanning angel error of the beam is smaller than 3 mrad, the principal of object location with time difference of reflected impulse radar signal is verified. These experiment results are in accord with analytical results of the point source approximation model. The experiments verify that the impulse radar can achieve the principle concept of beam forming and beam scanning.In order to test the target detection performance and the effectiveness of signal data processing method, we give experiment results for both static and dynamic target detected by the prototype system and processed by our signal processing method. Clear images of both static and dynamic objects are obtained, providing reference and data of the impulse radar target detection and data processing method for further study.