The orthogonal frequency division multiplexing (OFDM) chirp signal has its special merits of high-range resolution by exploiting a full bandwidth as multiple input multiple output (MIMO) radar signal. After simulation, there are some high peaks in the autocorrelation function and cross correlation function of conventional OFDM chirp signals, which may increase the correlation interference and reduce the detection performance of MIMO radar signal. This letter proposes to reduce the autocorrelation sidelobe peak (ASP) of OFDM chirp signal by subsection imitating the nonlinear frequency modulation (NLFM) signal’s time–frequency structure. Since a suitable difference should be made between the subchirp rates and subchirp carrier frequencies of each of the two designed OFDM chirp signals for reducing the cross correlation peaks (CP), the imitated NLFM waveforms’ design problem is solved by the proposed optimized method. At last, subchirps of the designed signals are coded by a group of optimized codes. The simulation shows the designed OFDM chirp signals have lower ASP and CP than the conventional ones and referenced previous OFDM signals, and their ASP decreases as the number of subchirps increases.

中文翻译：

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MIMO雷达低相关干扰模拟NLFM时频结构的OFDM Chirp波形设计

正交频分复用 (OFDM) 啁啾信号通过利用全带宽作为多输入多输出 (MIMO) 雷达信号，具有高距离分辨率的特殊优点。经仿真，常规OFDM chirp信号的自相关函数和互相关函数存在一些高峰值，可能会增加相关干扰，降低MIMO雷达信号的检测性能。这封信提出通过分段模拟非线性调频（NLFM）信号的时频结构来降低OFDM chirp信号的自相关旁瓣峰值（ASP）。由于应该在两个设计的 OFDM 线性调频信号中的每一个的子线性调频频率和子线性调频载波频率之间进行适当的差异以减少互相关峰值（CP），所提出的优化方法解决了模拟NLFM波形的设计问题。最后，设计信号的子啁啾由一组优化码编码。仿真表明，所设计的OFDM chirp信号比传统的和参考以前的OFDM信号具有更低的ASP和CP，并且它们的ASP随着subchirp数量的增加而降低。