Measurement-Based Multipath Corrections for GPS Sites

0003943 larson尽管发展了令人印象深刻的GPS基础设施，用于精确的轨道确定，并且在GPS建模和分析技术方面取得了许多进步，但仍然存在显着的误差源。随着全球范围内持续运行的GPS阵列继续部署，以研究信号低于1毫米/年的地球物理过程，消除所有系统误差的需求至关重要。多路径是当今GPS应用中最大的误差之一。目前还没有标准的技术来消除地球物理界使用的高精度GPS软件中的多径误差。GPS站点的多径环境校正失败会导致GPS估计的时变系统误差，从而降低系统的精度。这笔拨款的支持将用于开发一种校正GPS多路径误差的方法，该方法借鉴了航空航天工程师为航天器姿态确定开发的技术。该技术使用信噪比（SNR）来估计GPS相位观测值的修正。尽管GPS接收器经常收集信噪比数据，但目前尚未在高精度GPS软件中使用。这种基于信噪比的多径校正技术既可以用于旧的GPS数据集，也可以用于新的GPS数据集。由于该技术使用的是与相位数据同时采集的信噪比数据，因此对GPS站点的时变变化非常敏感。＊＊＊

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. ***