High Resolution Microwave Photonics Radar Real-time Imaging Based on Generalized Keystone and Frequency Scaling
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摘要: 微波光子雷达具有发射大带宽和高载频信号的能力,可实现2维高分辨的逆合成孔径雷达(ISAR)成像。研究相应的实时成像算法具有重要意义。但信号的高距离分辨率特点使得距离弯曲的空变性无法忽略,高载频特性使得相位历程的空变性无法忽略,导致传统的多普勒域实时成像算法成像效果差。另外,计算量较大的波束域成像算法不适用于大数据量的微波光子雷达信号。因此该文提出一种高效率的微波光子ISAR高分辨实时成像算法,该算法首先利用广义楔石变换(GKT)提取特显点相位,进而由相位调频率反演目标横向速度,最后利用速度估计结果结合频率变标(FS)算法完成空变的距离弯曲校正和方位匹配滤波成像。仿真和实测数据的处理结果验证了该算法的有效性。Abstract: Microwave photonic radars can transmit large bandwidth and high carrier frequency signals, which makes two-dimensional high-resolution Inverse Synthetic Aperture Radar (ISAR) imaging possible. It is important to study the corresponding real-time imaging algorithms. However, the high range resolution and high carrier frequency of the signal make the space curvature of the distance bend non-negligible. This is the reason for the poor imaging performance of the traditional Doppler real-time imaging algorithm. In addition, the computationally intensive beam domain imaging algorithm is not suitable for microwave photonic radar signals of large data volume. Therefore, a high-efficiency microwave photonic ISAR high-resolution real-time imaging algorithm is proposed in this paper. Firstly, this algorithm uses the Generalized Keystone Transform (GKT) to extract the phase of the special display point. Next, it inverts the target lateral velocity from phase modulation frequency. Finally, the result of velocity estimation and Frequency Scaling (FS) are used to correct the distance space-bending and conduct matched filtering imaging in azimuth. The simulation results and the measured data have been shown to verify the effectiveness of the proposed algorithm.
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Key words:
- Microwave photonic radar /
- ISAR /
- Real-time imaging /
- Lateral speed estimate /
- Frequency Scaling (FS)
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表 1 仿真数据参数
Table 1. Simulation parameters
信号带宽(GHz) 载频(GHz) 脉冲宽度(μs) 脉冲重复频率(Hz) 采样率(MHz) 参考斜距(m) 目标速度(m/s) 观测时间(s) 10 35 150 2000 500 1000 65 0.5 表 2 实测数据参数
Table 2. Measured data parameters
信号带宽(GHz) 载频 脉冲宽度(μs) 数据采样率(MHz) 脉冲重复频率(Hz) 成像距离(m) 观测时间(s) 10 Ka波段 150 500 6670 750 0.6 -
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