| 摘要: |
| 针对小孔径超视距目标探测时阵列孔径减小空域滤波性能下降的问题，提出了一种正交频分非线性调频（OFD-NLFM）的发射波形设计方法。首先以正切调频函数为频率函数对发射信号进行建模，详细说明了影响脉压性能的正切函数时间副瓣电平控制因子的选择方法，重点提出一种基于凸优化的脉压信号峰值旁瓣抑制算法，建立了脉压输出噪声功率最小的优化模型并进行求解。仿真表明，提出的正交频分非线性调频信号具有较好的正交性，采用凸优化加权算法后脉压主瓣宽度比传统线性调频信号降低约1/3，峰值旁瓣为-31.22 dB，旁瓣电平平均值小于-100 dB，具备更低的抗噪声和干扰性能，从波形设计和脉压处理角度改善了空域滤波性能的不足。 |
| 关键词: 天波超视距雷达 小孔径圆阵 目标探测 正交频分非线性调频信号 峰值旁瓣抑制 凸优化 |
| DOI： |
|
| 基金项目:国家自然科学基金资助项目（61172140） |
|
| OFD-NLFM waveform design for over-the-horizon target detection based on small aperture array |
| HE Qing,LUO Laiyuan,YAO Shanfeng |
| () |
| Abstract: |
| Since the performance of the array spatial filtering is depressed by using the small aperture array,the waveform design of orthogonal frequency division-nonlinear frequency modulation(OFD-NLFM) is used to overcome the declining performance. With the aid of the signal model based on the tangent frequency modulation function,the selection method for the parameter of time sidelobe level control is analyzed. In order to suppress range sidelobe,the convex optimization based on minimized noise power is proposed. The simulation shows that OFD-NLFM signal has fine orthogonality and the mainlobe of the pulse compression is 1/3 narrower than that of the linear frequency modulation(LFM) signal.The peak sidelobe level is -31.22 dB and the average of pulse compression is less than -100 dB. According to the result，the capability of noise and interference cancelation of the OFD-NLFM signal is better,which improves the spatial filtering performance. |
| Key words: skywave over-the-horizon radar small aperture array target detection OFD-NLFM signal peak sidelobe suppression convex optimization |
