用常规雷达对运动目标进行横向一维高分辨成象

讨论了一种常规低分辨力雷达对运动目标进行横向一维高分辨力成象的方法，并通过计算机仿真证实了方法的可行性。这有助于实现常规雷达对目标的识别和分类。     

2-D spatial-spectrum estimation for wide-band signals without a priori knowledge of the number of sources

In array signal processing,the existing methods for DOA estimation of wide-band signals are only related to the azimuth estimation when the number or sensors is known.It is shown that a circular array possesses several nice properties.2-D spatial-spectrum estimation for wide-band sources is performed by using a circular array of sensors with sample delay lines.Further,the Choi' s approach is extended,which was suggested to estimate DOA of narrow-band signals when the number of sensor was unknown,to wide-band signal processing.The extended approach is shown to be quite adequate for wide-band signal subspace spatial-spectrum estimation (BASS-LE),and a large aperture (r>λvin/2) circular array is found to possess superior resolution capability and robustness.     

平衡二阶相关免疫函数的构造

构造了一大类平衡的二阶相关免疫函数，从而给出了二阶相关免疫函数个数的一个更好的下界公式     

天线立体方向图的计算机处理

简述了计算机三维图形处理的基本原理，应用消隐算法对天线方向图进行计算和绘制，证明了程序设计的实用性和可行性。     

Simulation analysis of directivity and optimization of the array of the AlN thin film PMUT array

The relatively low piezoelectric constant of the aluminum nitride piezoelectric film limits the development and application of the piezoelectric micro-machined ultrasonic transducer based on the aluminum nitride. Therefore, the directivity of the piezoelectric micro-machined ultrasonic transducer array is studied for this problem. First, the far-field sound pressure and normalized directivity function of the transducer array are calculated according to the Rayleigh principle. Furthermore, the effects of array element radius, array element spacing, array element number and operating frequency on the beam width, direction sharpness angle and sidelobe level of the array are analyzed, and the transducer array is optimized. Finally, based on the optimization results, area and filling efficiency, the final structure size of the transducer array is determined and the sound pressure distribution visually simulated. The results show that the optimized transducer array has an ideal sound pressure distribution, good directivity and sharp main lobe. The-3dB beamwidth of the main lobe is about 9 ° and the sidelobe level is about 0.228.     

Fast DOA estimation methods for underdetermined wideband signals with a high accuracy

In order to handle the low accuracy of the algorithm DCS-SOMP, two underdetermined wideband direction of arrival estimation methods with a high accuracy are proposed from the perspective of multiple iteration. First, the wideband signal processing model using the sparse array is established and transformed into a distributed compressive sensing problem through sparse representation. Then, the noises are eliminated through matrix transformation. After that, an algorithm utilizing proximity searching is proposed to improve the estimation accuracy and an algorithm based on the refined grid is proposed to compensate grid mismatch. Simulation results show that the proposed algorithms outperform the DCS-SOMP with a higher estimation accuracy and possess the advantage in computational speed.     

Low complexity probability-based piecewise linear approximation of the sigmoid function

In order to improve the network recognition accuracy in the low complexity condition, a piecewise linear sigmoid function approximation based on the distribution probability of the neurons’ values is proposed only with one addition circuit. The sigmoid function is first divided into three fixed regions. Second, according to the neurons’ values distribution probability, the curve in each region is segmented into sub-regions to reduce the approximation error and improve the recognition accuracy. The slope of the piecewise linear function is set as 2-n, effectively reducing the hardware implementation complexity. Experiments performed on Xilinx’s FPGA-XC7A200T implement the MNIST handwritten digits recognition. The results show that the proposed method achieves a 97.45% recognition accuracy in a deep neural network and 98.42% in a convolutional neural network, up to 0.84% and 0.57% higher than other approximation methods only with one addition circuit.     

应用模拟韧化算法设计传感器阵方向图

介绍了一种传感器阵方向图设计的新方法,该方法应用快速模拟韧化算法(FSA),通过选择合适的能量函数,设计所需要的方向图.并给出一个设计实例.     

一种用于相控阵AEW雷达杂波抑制的新方法

提出了一种用于相控阵机载预警(AEW)雷达杂波抑制的简化辅助通道法,这种方法与Klemm提出的辅助通道法相比,采用的辅助通道数从N+K-1个[N为天线阵元(或列子阵)数,K为相干处理脉冲数]减少到4～6个。其性能与Klemm方法基本相同,而运算量大大减少,使实现成为可能。     

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