Space-Borne GNSS-R Ionospheric Delay Error Elimination by Optimal Spatial Filtering.

Qiuyang Zhang,Yang Liu,Junming Xia

doi:10.3390/s20195535

Abstract

Global Navigation Satellite System Reflectometry (GNSS-R) technology is a new and promising remote sensing technology, especially satellite-based GNSS-R remote sensing, which has broad application prospects. In this work, the ionospheric impacts on space-borne GNSS-R sea surface altimetry were investigated. An analysis of optimal values for spatial filtering to remove ionospheric delays in space-borne GNSS-R altimetry was conducted. Considering that there are few satellite-borne GNSS-R orbit observations to date, simulated high-resolution space-borne GNSS-R orbital data were used for a comprehensive global and applicable study. The curves of absolute bias in relation to the bilateral filtering points were verified to achieve the minimum absolute bias. The optimal filtering points were evaluated in both statistical probability density and quantile analysis to show the reliability of the selected values. The proposed studies are helpful and valuable for the future implementation of high-accuracy space-borne GNSS-R sea surface altimetry.

Highlights

Global Navigation Satellite System Reflectometry (GNSS-R) technology is a promising remote sensing technology, especially satellite-based GNSS-R remote sensing, which has broad application prospects [1,2]
Space-borne GNSS-R sea surface altimetry uses the single difference between the reflected navigation signal from the sea surface and the direct signal from the navigation satellite simultaneously received by the GNSS-R receiver loaded on a low earth orbit (LEO) satellite to retrieve the sea surface height
A single frequency ionospheric delay correction of the reflection point trajectory is obtained from the global ionosphere map (GIM) model, and noise is added to the ionospheric delay correction to simulate ionospheric delay measurements

Summary

Introduction

Global Navigation Satellite System Reflectometry (GNSS-R) technology is a promising remote sensing technology, especially satellite-based GNSS-R remote sensing, which has broad application prospects [1,2]. Compared with traditional microwave remote sensing technology, GNSS-R has the advantages of low power consumption, light weight, small size, low cost, and passivity. Since it can receive reflection signals from multiple satellites at the same time, its spatial resolution is higher than that of traditional microwave remote sensing technology, and its data can fill some areas that cannot be covered by traditional remote sensing technology. Compared to traditional sea surface altimetry, this technology can cover a vast region of the sea and help measure the sea surface height from a global view. Researchers can use TDS-1 data to retrieve sea surface height experiments [7]. The corresponding influence that affects sea surface altimetry accuracy was provided after the performance analysis of Sensors 2020, 20, 5535; doi:10.3390/s20195535 www.mdpi.com/journal/sensors

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Discussion

Conclusion