基于注意力机制和双向GRU模型的雷达HRRP目标识别

针对雷达高分辨距离像(HRRP)目标识别问题，传统方法只考虑样本的包络信息而忽略了距离单元间的时序相关性，该文提出了一种基于注意力机制的双向自循环神经网络模型。该模型将时域的HRRP数据通过滑窗分为正反两个序列，并将其分别通过两个相互独立的GRU网络进行特征提取，然后将同时刻提取到的特征进行拼接，从而利用了距离像双向的时序信息。考虑到不同时刻的序列对目标分类的重要性不同，通过注意力机制自适应地对各时刻隐层特征赋予不同的权值，最后根据加权求和后的隐层特征进行目标的识别与分类。实测数据实验结果表明，该文所提方法可以有效完成高分辨距离像的目标识别问题，并且在数据发生一定的时序偏移情况下，仍然可以准确找到目标区域。 

Radar High-resolution Range Profile Target Recognition Based on Attention Mechanism and Bidirectional Gated Recurrent

To address the problem of radar High-Resolution Range Profile (HRRP) target recognition, traditional methods only consider the envelope information of the sample and ignore the temporal correlation between the range cells. In this study, we propose a bidirectional self-recurrent neural network model based on an attention mechanism. The model divides the HRRP data in the time domain into two sequences, i.e., forward and backward using a sliding window, then extracts the features through two independent GRU networks, and splices the extracted features simultaneously, thus utilizing the bidirectional temporal information of HRRP. Considering that sequences at different moments have different degrees of importance to the target classification, different attention weights are assigned to the hidden layer features at each moment. Finally, the model uses the hidden features weighted summation to obtain target recognition and classification result. Experimental results show that the proposed method can effectively solve the target recognition problem of HRRP, and that the target area can still be accurately identified when the time shift occurs.