GNSS-R接收机双天线基带信号协同处理关键技术研究

With the application of the GNSS technology in Remote Sensing, GNSS-R has been rapid developed, attracting wide attentions from scholars. However, the existing GNSS-R receiver is still using the basic GNSS receiver structure, with obvious drawbacks including the coherent integration time limitation, direct leakage interference and practical carrier phase stability problems. To solve these problems, collaborative processing on baseband signals of dual antennas is proposed in this project, which makes full use of the relationship between the direct signal and the reflected signal of GNSS-R receiver. The main research contents include “collaborative correlation” based on the information from the direct signal estimation, directing leakage correlation reconstruction and elimination based on the directing signal parameter estimation, and direct channel tracking loop aided reflection signal carrier phase tracking technology. In addition, the collaborating processing prototype will be realized in a GNSS software receiver, which could be used to verify these technologies. It is expected that researches of this program will improve the output DDM quality and reflected signal carrier tracking sensitivity and accuracy of the GNSS-R receiver, and provide theoretical and experimental basis for the special GNSS-R receiver development, at last push forward the GNSS-R technique application.

随着GNSS技术在遥感领域应用的不断扩展，GNSS-R得到了迅速的发展。然而，现有GNSS-R接收机仍采用基本的GNSS接收机处理结构，存在相干积分时间受限、直射泄漏干扰，以及载波相位稳定性差等问题。针对这些问题，本项目拟根据GNSS-R接收机的自身结构特点，开展GNSS-R接收机双天线基带协同处理技术研究。项目主要研究内容包括：基于直射信号的估计信息的双天线信号“协同相关”处理技术，基于直射信号的估计参数的直射泄漏干扰相关峰重构与剔除技术，以及直射信号载波跟踪环辅助的反射信号载波跟踪技术。在此基础上，项目拟建立基于软件接收机的GNSS-R双天线信号协同处理原型，对上述技术进行实验验证，从而达到提高输出DDM质量和反射信号载波跟踪灵敏度的目的。项目的研究将为GNSS-R专用接收机的发展提供理论参考和实验依据，进一步推动GNSS-R技术向前发展。

随着GNSS技术在遥感领域应用的不断扩展，GNSS-R得到了迅速的发展。然而，现有GNSS-R接收机仍采用基本的GNSS接收机处理结构，存在相干积分时间受限、直射泄漏干扰，以及载波相位稳定性差等问题。针对这些问题，本项目拟根据GNSS-R接收机的自身结构特点，开展了GNSS-R接收机双天线基带信号协同处理技术研究。课题首先建立了双频软件接收机平台，基于北斗双频中频数据，研究了双频信号辅助捕获与跟踪算法。基于前期的工作基础，建立了多天线硬件接收机处理平台，可同时采集多路中频信号，进行算法性能分析；然后，针对GNSS-R直射信号与反射信号的特殊关系，重点研究了直射信号辅助反射信号的弱信号捕获与跟踪架构，并对其算法性能进行了详细的分析；在此基础上，提出了一种基于后相关处理的直射信号干扰扣除算法，算法利用直射信号的参数对其相关参数进行提取，并对其相关峰进行重构，在反射信号捕获和跟踪时进行扣除，从而达到剔除直射干扰的效果；最后，针对GNSS-R海面风速反演的应用需求，我们在前期软件接收机的平台上设计了一套GNSS-R软件接收机，提出了基于匹配滤波的FFT并行处理算法，有效提高了DDM输出效率。为了验证GNSS-R的应用效果，本课题还利用开源的海面数据，研究了海面风速反演算法，利用神经网络对海面风速反演算法进行了改进。项目执行期间共发表论文6篇，其中SCI收录3篇，EI会议论文2篇，中文核心论文1篇；授权国家发明专利3项，申请发明专利2项；培养博士后1人，博士生1人，硕士生5人；实际成果达到了预期。