基于延迟多普勒图像的GNSS-R有效波高反演方法

GNSS-R significant wave height inversion method based on delay-Doppler maps

为了实现海面有效波高的探测,本文利用全球导航卫星系统反射信号(Global Navigation Satellite System Reflection,GNSS-R)提出了一种利用延迟多普勒图像进行信噪比计算的有效波高反演方法。相比传统雷达等主动探测,GNSS-R是利用卫星信号前向散射的被动观测,无需发射机,具有信号源多、功耗小、成本低、重量轻等优势,便于在星载、机载以及船载平台上进行搭建。由于海面波高的不同,接收机接收到的反射信号也不同。通过对反射信号的分析,可以得到不同反射面的物理特征信息,从而反演出我们所需的海面波高信息。本文通过反射信号生成延迟多普勒图像,并给出相应的信噪比定义,从而获得有效波高。为验证本文提出算法的可行性,本文进行了船载有效波高反演试验,并和传统利用干涉复数场(Interference Complex Field,ICF)进行反演的估算方法进行了性能对比和验证。结果表明,所提算法的均方根误差为0.098 m,R2值为77%,相关系数为0.82,均优于ICF方法,且与测波雷达的有效波高真值数据表现出更好的一致性,提升了基于GNSS-R技术进行有效波高估算的精度,能够为船舶航行的海况信息感知提供服务。

In order to realize the detection of significant wave height,this paper uses GNSS-R(Global Navigation Satellite System Reflection)to propose an significant wave height inversion method based on delay-Doppler maps for signal-to-noise ratio(SNR)calculation.Compared with active detection such as traditional radar,GNSS-R is a passive observation using forward scattering of satellite signals,without transmitter.It has the advantages of more signal sources,low power consumption,low cost and light weight,which is convenient to be built on space-borne,airborne and ship-borne platforms.Due to the different significant wave height,the reflected signal received by the receiver is also different.Through the analysis of the reflected signal,we can get the physical characteristic information of different reflectors,so as to reflect the required significant wave height information.In this paper,the delay-Doppler map is generated by the reflected signal,and the corresponding SNR definition is given to obtain the significant wave height.In order to verify the feasibility of the algorithm proposed in this paper,the inversion experiment of significant wave height on board is carried out,and the performance is compared and verified with the traditional estimation method using interference complex field(ICF)for inversion.The results show that the root mean square error of the proposed algorithm is 0.098 m,the R2 value is 77%,and the correlation coefficient is 0.82,which are better than those of the ICF method.The proposed algorithm has better consistency with the significant wave height data of the wave radar,which improves the accuracy of the significant wave height estimation based on GNSS-R technology,and can provide services for the significant state information perception of ship navigation.