Combining Range Profile Of A Step Frequency Radar Based On PowerPC

Modern radar has a long developing history. Its role has not been limited to detection, tracking and distance-measurement of the target invisible. With the improvement of sophisticated signal processing algorithms and hardware level, there is an inevitable trend for modern radar to be more intelligent and refinement. Getting more details about the targets would be helpful for classification. As we know,higher range resolution radar requires a greater transmission bandwidth, but large instantaneous bandwidth put s forward to higher requirements to the parameters configuration of the radar transmitter, receiver and antenna array. Meanwhile, the higher radar effective distance decides that the energy of emitted signals cannot be too small, which means that a large width is needed under the precondition of a constant transmitter peak power. The processing of SFW(stepped-frequency waveform) combines the advantages of both stepped frequency signal and chirp signal. Stepped-frequency characteristics make it easy to obtain a large bandwidth by integrating of multi-pulse, and chirp modulation characteristics make it easy to reduce the number of sub-pulses during the synthesis process of wideband signals. At the same time, it also increases the transmission data rate of the radar system to get HRRP(high range resolution profile).This paper describes the general algorithms for stepped-frequency radar signal to generate HRRP, focuses on the frequency domain bandwidth synthesis algorithm and shows how to use stepped frequency echo to achieve the ship target's HRRP. The main contents are summarized as follows:First, mathematically model of stepped frequency radar signal is discussed. Using the formula derived from the mathematical reason which is capable of generating high resolution profile. Based on these, the mathematical model of stepped-frequency chirp signal is also introduced.Then the time domain wideband synthesis algorithm and frequency domain broadband synthesis algorithm on SFW signal are compared with target extraction algorithm on stepped-frequency signal. The relationship between important parameters and realization method in project are discussed. The error caused by the radar target radial motion is calculated. A number of key points and corresponding measures need to be focused on in engineering practice are listed.Finally, a detailed description of the frequency domain synthesis algorithm to achieve HRRP on Power PC-based hardware platform is given. Then the paper talks about the basic structure of the hardware platform, data processing, signal processing, computational load estimation, and task response mechanism. To achieve better results, using simulation data and measured data to test the running firmware functions.