王向荣, 黄嘉怡, 谢晋东, 等. 面向艇载气象雷达的稀疏相控阵优化设计[J]. 信号处理, 2024, 40(9): 1569-1586. DOI: 10.12466/xhcl.2024.09.001.
引用本文: 王向荣, 黄嘉怡, 谢晋东, 等. 面向艇载气象雷达的稀疏相控阵优化设计[J]. 信号处理, 2024, 40(9): 1569-1586. DOI: 10.12466/xhcl.2024.09.001.
WANG Xiangrong, HUANG Jiayi, XIE Jindong, et al. Sparse phased array optimization for airship-borne weather radar[J]. Journal of Signal Processing, 2024, 40(9): 1569-1586. DOI: 10.12466/xhcl.2024.09.001.
Citation: WANG Xiangrong, HUANG Jiayi, XIE Jindong, et al. Sparse phased array optimization for airship-borne weather radar[J]. Journal of Signal Processing, 2024, 40(9): 1569-1586. DOI: 10.12466/xhcl.2024.09.001.

面向艇载气象雷达的稀疏相控阵优化设计

Sparse Phased Array Optimization for Airship-Borne Weather Radar

  • 摘要: 台风是一种持续性的热带气旋,常带来狂风、暴雨等灾害天气。平均每年约有七次台风登陆我国,对我国人口密集的东南沿海和部分内陆地区带来严重影响。气象雷达具有对台风等灾害天气的探测和预警能力,但现有的气象雷达多为地基相控阵雷达,距离远且分辨率低,对台风内部结构观测不清,导致在台风强度和路径的预测上存在着较大的不确定性。为降低台风灾害带来的损失,北京航空航天大学承担的国家自然科学基金重大科研仪器研制项目(简称“大仪器”项目)提出由临近空间飞艇搭载气象雷达对台风进行追踪抵近探测,提供台风内部结构长时、精细的观测数据。不同于地基雷达,临近空间飞艇独特的平台限制约束了气象雷达的重量、功耗、尺寸等成本参数,而实现台风探测的高性能亟须大孔径阵列。因此,艇载台风探测雷达的技术难点在于:如何用最低的成本实现最高的性能。在“大仪器”项目的资助下,本文提出一种稀疏相控阵气象雷达,可以在降低系统成本的同时实现高分辨率探测。本文的主要贡献总结如下:首先,对单天线气象回波的时间序列进行模拟仿真,扩展至多天线相控阵气象雷达的回波数据模拟,并通过多普勒分析验证其准确性;然后,考虑稀疏化均匀间隔的相控阵列,通过减少阵元数降低硬件成本的同时,保持高分辨率的波束扫描与接收;最后,联合优化阵列构型和权重系数,权重系数满足恒模约束以最大化雷达发射功效,从而进一步压低副瓣电平来改善气象雷达的抗干扰性能。仿真和实验结果表明,相控阵雷达能够实现准确高效的气象探测,稀疏阵的引入使系统在维持高分辨率的同时降低了硬件成本。具体地,在相同阵元数的条件下,稀疏阵在对气象回波反射率、多普勒频率及谱宽的估计上,都展现明显优于均匀阵的效果。

     

    Abstract: ‍ ‍Typhoons are persistent tropical cyclones that often bring gales, rainstorms, and other disastrous weather. On average, approximately seven typhoons occur every year in China, which has severe implications for the densely populated southeast coast and some inland areas. Meteorological radar observation can detect and predict typhoons and other disastrous weather; however, existing meteorological radars are mostly ground-based phased array radars with long-distance coverage but low spatial resolution. They cannot observe the internal structure of typhoons clearly, resulting in inaccurate predictions of typhoon intensity and travel path. The National Natural Science Foundation (NSF) of China’s Major Research Instrument Development Project (referred to as the “Big Instrument” project) undertaken by Beihang University proposed to reduce the losses caused by typhoon disasters by using near-space airships equipped with meteorological radars to track and detect typhoons, providing long-term and detailed observation data on the internal structure of typhoons. Unlike ground-based weather radars, the unique platform limitations of near-space airships constrain the cost parameters of meteorological radars, such as weight, power consumption, and size. However, achieving high-performance typhoon detection urgently requires large aperture arrays. Therefore, the technical difficulty of airship-borne typhoon detection radar lies in achieving the highest performance at the lowest cost. Supported by the NSF “Big Instrument” project, this study proposes a sparse phased array meteorological radar that can achieve high-resolution detection while reducing system overhead. The main contributions of this study are summarized as follows: First, the time series of meteorological echoes received by a single antenna was simulated and then extended to simulate the echo data of multi-antenna phased array meteorological radars, with the accuracy verified via the Doppler analysis. Second, we considered the sparse phased array via antenna selection from a uniform counterpart, decreasing the number of elements to reduce the hardware cost while maintaining high-resolution meteorological detection. Finally, the array configuration and beamforming weights were jointly optimized. The weight coefficients are entailed to satisfy the constant modulus constraint to maximize the radar transmission power efficiency, and the sidelobe level is further reduced to improve the anti-interference performance of the meteorological radar. The simulation and experimental results demonstrated that phased array radars could achieve accurate and efficient meteorological detection, and the introduction of sparse arrays reduced the hardware cost while maintaining a high resolution. Specifically, using the same number of array elements, the optimized sparse array exhibited superior performance to its uniform counterpart in estimating meteorological echo reflectivity, Doppler frequency, and spectral width.

     

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