Measurement-Based Multipath Corrections for GPS Sites

0003943拉尔森尽管GPS基础设施的发展令人印象深刻的精确轨道确定和许多进步的GPS建模和分析技术，重大的误差来源仍然存在。 由于在世界各地继续部署连续运行的全球定位系统阵列，以研究信号低于1毫米/年的地球物理过程，因此消除所有系统误差的必要性至关重要。 多路径是当今GPS应用中最大的误差之一。目前没有标准的技术来消除地球物理学界使用的高精度GPS软件中的多路径误差。 若未能校正全球定位系统所在地点的多路径环境，会在全球定位系统的估计中产生随时间变化的系统误差，从而降低系统的准确度。这项拨款将用于发展一种方法，以校正全球定位系统的多路径误差，该方法借用了航天工程师为航天器姿态确定而开发的技术。 该技术使用信噪比（SNR）来估计GPS相位观测值的校正。 虽然由全球定位系统接收器例行收集，但信噪比数据目前并不用于高精度全球定位系统软件。 这种基于SNR的多径校正技术既可以用于较旧的数据集，也可以用于新的GPS数据。 由于该技术使用与相位数据同时收集的SNR数据，因此它对GPS站点的时变变化敏感。 ***

0003943LarsonDespite the development of an impressive GPS infrastructure for precise orbit determination and many advances in GPS modeling and analysis techniques, significant error sources remain. As continuously operating GPS arrays continue to be deployed throughout the world to study geophysical processes with signals below 1 mm/yr, the need to eliminate all systematic errors is critical. Multipath represents one of the largest errors in GPS applications today. There is currently no standard technique to remove multipath errors in high precision GPS software used by the geophysics community. Failure to correct for the multipath environment at a GPS site produces a time-varying systematic error in GPS estimates which degrades the accuracy of the system.Support form this grant will be used to develop an approach for correcting GPS multipath errors that borrows on technologies developed by aerospace engineers for spacecraft attitude determination. The technique uses the signal-to-noise ratio (SNR) to estimate corrections to the GPS phase observables. Although routinely collected by GPS receivers, SNR data are not currently used in high precision GPS software. This SNR based multipath correction technique can be used both on older datasets as well as new GPS data. And because the technique uses SNR data collected simultaneously with the phase data, it is sensitive to time varying changes at GPS sites. ***