At present, the raw echo data captured by spaceborne SAR is usually downlinked to the ground stations for imaging and analysis. If the SAR data can be processed on-board, the processing results could be transmitted to users directly through broadcast distribution, which can greatly reduce the delay time for emergency applications. However, on-board processing implementation faces many challenges due to the space radiation environment and limited resources of the satellite. In this paper, an FPGA-based implementation of ship detection for on-board processing is proposed, which has high efficiency in logic and memory resources. First, the hardware-oriented clustering approach is proposed. Image processing operations with similar regularity of data access can be mapped in one processing engine, which can reduce the employment of logic resources. Second, the concept of the data-buffering cycle (DBC) is proposed. The DBC provides a method to analyze the intermediate data and optimize the memory reuse. Finally, based on the above optimization methods, the FPGA-based implementation for a ship detection algorithm is presented. Compared with the traditional methods, the experimental results show the efficacy of our proposed method with lower consumption in logic and memory resources.

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SummaryIn order to meet the needs of the application of optical detection and recognition of ship targets in complex sea environment, based on the full link of optical remote sensing detection, the radiation transmission mechanism of ship target characteristics is analyzed. Then, the radiation characteristics model of ship target, the radiation model of ship target thermal wake, and the radiation characteristics model of sea background are established, and the simulation calculation of focal plane radiation characteristics for sea surface ship target is realized according to the space‐based detection and imaging mechanism; Finally, based on the simulation calculation model, the variation law of ship target radiation characteristics under different sea surface conditions and different imaging time are analyzed, which can provide theoretical basis and scientific guidance for the key index design of Space‐Based Surveillance and detection system and the optimization of target detection and recognition algorithm.