Two Types Of Compressed Waveforms Design And Performance Analysis For Doppler

The radar emitted waveforms not only decide the methods of signal processing, but also directly affect the system resolution,the measurement precision and the ability of clutter rejection. Thus, the waveform designing is becoming the important content of optimal synthesis in radar system and the important branch in the modern radar theory. In this paper, firstly according to the signal's one dimensional ambiguity function, we propose a novel method for the designing of nonlinear frequency modulated(NLFM) waveform, based on the polynomial fitting. In this method, we can easily get the NLFM signals with the different window functions, which provide the smart space for the waveform designing; In X-band and multi-emitted and multi-received system, the traditional coherent emitted signals can form the coherent speckle while irradiating the surround. In the paper, we propose the combined waveform of the phase coded stepped frequency and the m-sequences. By optimizing the lowest side-lobe level of m-sequences'autocorrelation function and cross-correlation function, the desire resolution of the distributed space-based radar system is satisfied; In addition, we propose an improved form of ambiguity function of phase coded stepped frequency signal, which can well materialize the coupling of the time and frequency. Finally, lots of simulation and performance analysis demonstrate the validity of all the methods presented in the paper.