基于载波相位提取与重构技术的高精度GNSS-R测高及软件接收机设计研究

Sea surface height monitoring is an important technique to monitor the marine dynamic environment and detect the marine gravity. GNSS-R technology is a new method developed in recent years in remote sensing, which becomes a hot topic soon because of its characteristics, such as low cost, low power consumption, all-weather and all-day measurement, multiple source, wide coverage and high spatial and temporal resolution. Compared with the code-ranging technique, GNSS-R carrier phase measurement can achieve higher measurement precision. However, in the case of the wind and the sea surface is rough, the diffuse reflection of the carrier phase is prone to phase shift and phase jump, so that the receiver lost the lock and tracking of carrier phase, which hinder the carrier phase as a high-precision GNSS -R altimetric observation. In this research project, the following researches will be carried out for this problem: .1) Research on carrier-phase reconstruction technique of rough sea surface reflection .2) Based on 1) algorithm, designing one software GNSS-R receiver which is suitable for airborne and space-borne GNSS-R carrier-phase altimetry; .3) Making experimental tests of the above software GNSS-R receiver, and analyzing the reliability of carrier-phase reconstruction technology.. In this research project, we will devote ourselves to realizing high-precision GNSS-R carrier-phase observation and building a complete set of data processing platform to improve the capability of marine management in China.

海洋测高是探测海洋动力环境和海洋重力场的重要方法之一，GNSS-R测高有低成本、多信号源和宽覆盖等特点，具备对全球海洋进行高时空分辨率监测的能力，成为一个极具发展潜力的大地测量新方向。与码相位测高相比，GNSS-R载波相位测高可以获得更高的测量精度。然而，在海面有风浪、反射面较为粗糙的情况下，散射信号的载波相位易发生相移和相跳，使接收机失去了对载波相位的锁相与追踪，阻碍了载波相位观测作为高精度GNSS-R测高的观测量。因此，本项目针对这一问题，进行如下研究：1）粗糙海面反射的载波相位提取与重建技术研究；2）设计出适用于GNSS-R高精度载波相位测高的软件接收机；3）利用设计出的接收机进行海面测高实验，验证算法和软件的可靠性。本课题最终构建一套完备的高精度GNSS-R载波相位测高观测与数据处理平台，为提高我国进行海洋管理的能力做技术保障。

基于GNSS卫星的反射信号进行海面高度监测是近几年来发展起来的新的测高手段。相对于传统的卫星测高和验潮站对于海面高度的观测，它可实现全天候、全天时、多信号源、宽覆盖、高时空分辨率的海面高度观测，为海面高度监测提供了新的手段。本项目针对当前GNSS-R海面高度反演时受多种因素影响精度不高的问题，提出新算法，结合改进的软件接收机来实现厘米级的海面高度测量。项目执行过程中，在实现以原GNSS接收机中载波相位组合来反演海面高度的基础上，利用新设计的软件接收机，提取了码伪距和载波相位观测值，实现了岸基和船载GNSS-R测高。其中，利用载波相位观测值实现的海面高度反演，精度达到厘米级，满足原项目设计要求。本项目的实现，为进一步推动星载GNSS-R测高提供了理论基础。并且，该项目所设计的软件接收机也可用于GNSS-R对地表其它因素的反演中，进一步推动了GNSS-R技术的发展。