Troposcatter Radar Spectrum Signal Modeling And Processing

Nowadays, our country needs to grasp the dynamics of aircraft carriers and other large ships on West Pacific, and the radar spectrum monitoring based on microwave tropo scatter can meet the characteristics of high space, time coverage and real-time. Compared with the traditional passive detection, troposcatter radar signal has special properties.First, pitch scattering model is established on the base of troposcatter theory, with analysing the influence of model parameters on the energy accumulation, then the calculation of the optimal receiving antenna pitch angle in broadband detection system is provided. To study the effect of target pitch multi-beam to the system, analysis is made combined with the typical radar signal pitch characteristics. After determining the optimal pitch of receiving antenna, the beam energy within 2 degree pitch is obtained with the accumulation of target pitch multi beam, and the beams of different pitch has a group delay.Secondly, azimuth scattering model is built to study the receiving antenna azimuth how to aggregate the impact energy, and the effect of the target azimuth static and scanning on direction detection. After analyzing the relationship between these effects and other important parameters, which is explained with the typical radar signal, we conclude that the receiving antenna azimuth need diversity reception, and it exists minimum direction detection error and minimum virtual fuzzy angle regardless of the receiving system. The higher the receiving antenna is, the more benefits the direction detection has.The array receiving signal model is established with analyzing the relationship of array elements phase changes, and compared with the traditional values to improve the traditional array signal processing algorithms. It is obtained that the one-dimensional uniform linear array of phase difference between array elements and element numbers shows a linear relationship, but there is phase diffusions among each elements of troposcatter signal receiving array, which causes the error and fuzzy of direction detection.Finally, the extensible modular high speed synchronous sampling recording system is designed and implemented. The whole system is extensible and modular with 14 bit 180MHz continuous sampling, and the one cascade clock module can achieve 128 synchronous sampling and recording.