机载毫米波雷达多普勒中心频率估计方法

Doppler centroid frequency estimation method for airborne millimeter-wave radar

摘要:

由于毫米波雷达波长短，在一定的脉冲重复频率(PRF)条件下更容易产生方位采样模糊，且成像质量受多普勒中心频率估计影响较大。为此，提出一种联合惯导信息和回波包络对称匹配的多普勒中心频率估计方法，能够为毫米波合成孔径雷达(SAR)成像精确估计多普勒中心频率进而实现稳定连续出图的目的。先利用惯导信息解算方位采样模糊数，再利用提出的回波包络对称匹配方法实现多普勒中心频率精确估计。该方法估计精确度高且算法复杂度低，适用于不同频段雷达和多种时频域成像算法，具有良好普适性。通过对SAR图像序列的连续估计以及算法性能对比，验证了本文算法的有效性。

Abstract:

Due to the short wavelength of millimeter-wave radar, azimuth sampling ambiguity is more likely to occur under certain Pulse Repetition Frequency(PRF) conditions, and the imaging quality is greatly affected by the estimation of the Doppler center frequency. To address this, a method for estimating the Doppler center frequency by combining inertial navigation information and echo envelope symmetry matching is proposed, which can accurately estimate the Doppler center frequency for millimeter-wave Synthetic Aperture Radar(SAR) imaging, thereby achieving the goal of stable and continuous image generation. Firstly, inertial navigation information is employed to resolve azimuth sampling ambiguity, and then the proposed echo envelope symmetry matching method is adopted to achieve precise estimation of the Doppler center frequency. This method has high estimation accuracy and low algorithm complexity, making it suitable for different frequency band radars and various time-frequency domain imaging algorithms, demonstrating good universality. The effectiveness of the algorithm in this paper is verified through continuous estimation of SAR image sequences and performance comparison of the algorithms.