This study conducts an in-depth evaluation of imaging algorithms and software and hardware architectures to meet the capability requirements of real-time image acquisition systems, such as spaceborne and airborne synthetic aperture radar (SAR) systems. By analysing the principles and models of SAR imaging, this research creatively puts forward the fully parallel processing architecture for the back projection (BP) algorithm based on Field-Programmable Gate Array (FPGA). The processing time consumption has significant advantages compared with existing methods. This article describes the BP imaging algorithm, which stands out with its high processing accuracy and two-dimensional decoupling of distance and azimuth, and analyses the algorithmic flow, operation, and storage requirements. The algorithm is divided into five core operations: range pulse compression, upsampling, oblique distance calculation, data reading, and phase accumulation. The architecture and optimisation of the algorithm are presented, and the optimisation methods are described in detail from the perspective of algorithm flow, fixed-point operation, parallel processing, and distributed storage. Next, the maximum resource utilisation rate of the hardware platform in this study is found to be more than 80%, the system power consumption is 21.073 W, and the processing time efficiency is better than designs with other FPGA, DSP, GPU, and CPU. Finally, the correctness of the processing results is verified using actual data. The experimental results showed that 1.1 s were required to generate an image with a size of 900 × 900 pixels at a 200 MHz clock rate. This technology can solve the multi-mode, multi-resolution, and multi-geometry signal processing problems in an integrated manner, thus laying a foundation for the development of a new, high-performance, SAR system for real-time imaging processing.
We consider moderately interacting particle systems with singular interaction kernel and environmental noise. It is shown that the mollified empirical measures converge in strong norms to the unique (local) solutions of nonlinear Fokker-Planck equations. The approach works for the Biot-Savart and Poisson kernels.
A nonstationary Poisson model describing the occurrences of clustering earthquakes is developed. This model, characterized by a U-shape mean-occurrence-rate function, simulates the decreasing, nearly constant, and increasing variations of the mean occurrence rates at the instants soon after the last event in the current cluster, in the waiting period between the current and the next clusters, and just before the next cluster, respectively. The parameters of such a U-shape function are determined empirically from the earthquake catalog. A simple example is presented to show the difference in the estimated mean occurrence rate and in the induced seismic risk between different Poisson occurrence models.
SAR real-time imaging processing system on Airborne or spaceborne platform strict in power volume and weight, in order to meet the requirements of the platform and increasing the flexibility of system application, this paper presents a kind of SAR real-time imaging technology, based on field programmable gate array (FPGA) dynamic reconfiguration technology. First of all, the technology optimize the algorithm then classify whole flow into dynamic and static parts. the dynamic part implement numerical calculation, the static part implement the process control, data storage and peripheral interface, Then based on the dynamic reconfiguration technology, design processing system, and research data interface, data storage, process control and data operation; At last using unmanned aerial vehicle (uav) flight data verify the system performance. the results is that the system run at 200 MHZ frequency to process data which size is 65536 x 65536 need 85.9s, and the system using resources about 50% lower than the traditional method, the power consumption decrease by 20%. Through the experiments have proved the effectiveness of the technology, laid the foundation of designing the high performance real-time imaging processing system on airborne or spaceborne platform.INDEX TERMS Field-programmable gate array (FPGA), Real time imaging processing, reconfigurable computation, synthetic aperture radar (SAR)
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