时域延时宽带波束形成与通道均衡技术研究与实现

发布时间：2018-08-26 07:31

【摘要】：采用数字波束形成技术的阵列天线由于具有方向图综合优化灵活和空域自适应抗干扰能力强等特点,已经得到了越来越广泛的应用。随着信号带宽的增加,若仍采用窄带波束形成的移相方法实现,会产生波束指向在空间的色散现象,当孔径渡越时间大于或者接近信号带宽的倒数时,波束形成的性能严重下降。本文主要针对上述问题开展相关技术研究,主要的研究工作包括:本文首先,开展了基于时域真延时的宽带波束形成算法及通道均衡技术的研究。通过数字电路触发器和基于Farrow结构的可变分数延时滤波器来实现精度达到皮秒量级的可控延时;从解决通道失配对宽带波束形成的影响出发,开展了频域通道均衡算法以及改进频域均衡算法的研究。通过理论推导、算法优化和仿真测试验证了 Farrow结构的可变分数延时滤波器和频域改进通道均衡算法在宽带波束形成系统中应用的可行性和有效性。接着,开展了相关技术的实现验证研究,提出了将时域真延时宽带波束形成与通道均衡技术一体化设计的新方案。以8通道宽带中频数字波束形成处理电路为验证平台,开展算法在K7系列FPGA的移植和实现。为了验证所设计的一体化方案的正确性,并对相关性能指标进行测试,专门构建了宽带8通道中频信号模拟系统,组成实测验证系统。在该实验系统上,测试了基于Farrow结构的可变延时宽带波束形成与通道均衡的性能,实测结果表明,延时均方误差优于6ps,在60%的相对带宽范围内,通道均衡剩余幅度和相位失配均方误差分别优于0.4dB和1.5°,并可以通过可变延时实现宽带波束扫描,方向图性能优越,指向误差小于1°。本文的研究内容和实验测试结果为时域真延时宽带波束形成技术的实际应用奠定了坚实的基础。
[Abstract]:The array antenna with digital beamforming technology has been widely used because of its flexibility in pattern synthesis and optimization and strong adaptive anti-jamming capability in spatial domain. With the increase of the signal bandwidth, if the narrowband beamforming method is still used to realize the phase shift, the beam-pointing dispersion phenomenon will occur. When the aperture transit time is greater than or close to the reciprocal of the signal bandwidth, The performance of beamforming is severely degraded. The main research work includes: firstly, the research of wideband beamforming algorithm and channel equalization technology based on time domain true delay is carried out. Digital circuit flip-flop and variable fractional delay filter based on Farrow structure are used to realize the controllable delay with picosecond precision, and the effect of channel mismatch on wideband beamforming is solved. The frequency domain channel equalization algorithm and the improved frequency domain equalization algorithm are studied. By theoretical derivation, algorithm optimization and simulation test, the feasibility and effectiveness of the Farrow structure variable fractional delay filter and the frequency domain improved channel equalization algorithm in wideband beamforming system are verified. Then, the implementation and verification of related technologies are studied, and a new scheme is proposed to integrate time domain true delay wideband beamforming and channel equalization. On the platform of 8 channel wideband if digital beamforming processing circuit, the algorithm is transplanted and implemented in K7 series FPGA. In order to verify the correctness of the designed integrated scheme and to test the related performance indexes, a broadband 8-channel if signal simulation system is specially constructed, and a practical verification system is constructed. In this experimental system, the performance of variable delay wideband beamforming and channel equalization based on Farrow structure is tested. The measured results show that the delay mean square error is better than 6 ps. within the relative bandwidth range of 60%. The residual amplitude and phase mismatch mean square error of channel equalization is better than that of 0.4dB and 1.5 掳respectively, and the wideband beam scanning can be realized by variable delay. The pattern performance is superior and the pointing error is less than 1 掳. The research contents and experimental results of this paper have laid a solid foundation for the practical application of time domain true delay broadband beamforming technology.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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