Ding Yujiao, Guo Shuxu, Zhou Weinan, Dong Wei
Appl Opt. 2021 Sep 20;60(27):8534-8539. doi: 10.1364/AO.433902.
We propose a microwave photonic compressive sensing radar for distance and velocity measurement. First, a de-chirped signal that carries distance or velocity information is extracted between the transmitted and received signals in the proposed system. Then it is mixed with a pseudo-random bit sequence in the optical domain using a Mach-Zehnder modulator. After that, the de-chirped signal can be acquired by a photodetector and an analog-to-digital converter (ADC) at a sub-Nyquist sampling rate. Finally, a reconstruction algorithm can be used to recover the de-chirped signal. In our test, the bandwidth of ADC can be shortened from 2 GHz to 500 MHz, leading to a compression factor of four. A series of frequencies from 1.043 GHz to 1.875 GHz can be compressed with a 500-MHz ADC and recovered using a reconstruction algorithm. For a moving target, the Doppler frequency shift can be calculated, and the direction of the moving target can be distinguished. The maximum relative error of distance measurement is 0.21%. The maximum relative error of velocity measurement is 2.6%. The signal-to-noise ratio can be developed from ∼15 to ∼30. This microwave photonic compressive sensing radar can achieve distance and velocity measurements using few samples. Also, it provides a large bandwidth of system operation and reduces data processing and storage pressure.
我们提出了一种用于距离和速度测量的微波光子压缩感知雷达。首先，在所提出的系统中，在发射信号和接收信号之间提取携带距离或速度信息的去啁啾信号。然后，使用马赫-曾德尔调制器在光域中将其与伪随机比特序列混合。之后，去啁啾信号可以由光电探测器和模数转换器（ADC）以亚奈奎斯特采样率获取。最后，可以使用重建算法来恢复去啁啾信号。在我们的测试中，ADC的带宽可以从2 GHz缩短到500 MHz，压缩因子为4。一系列从1.043 GHz到1.875 GHz的频率可以用500 MHz的ADC进行压缩，并使用重建算法恢复。对于移动目标，可以计算多普勒频移，并区分移动目标的方向。距离测量的最大相对误差为0.21%。速度测量的最大相对误差为2.6%。信噪比可以从约15提高到约30。这种微波光子压缩感知雷达可以使用少量样本实现距离和速度测量。此外，它提供了较大的系统工作带宽，并减轻了数据处理和存储压力。
