On Satellite-Borne GPS Data Quality and Reduced-Dynamic Precise Orbit Determination of HY-2C: A Case of Orbit Validation with Onboard DORIS Data

Hengyang Guo,Jinyun Guo,Bing Ji,Zhouming Yang,Hailong Peng,Mingsen Lin,Guangzhe Wang,Linhu Qi

doi:10.3390/rs13214329

Abstract

Haiyang-2C (HY-2C) is a dynamic, marine-monitoring satellite that was launched by China and is equipped with an onboard dual-frequency GPS receiver named HY2_Receiver, which was independently developed in China. HY-2C was successfully launched on 21 September 2020. Its precise orbit is an important factor for scientific research applications, especially for marine altimetry missions. The performance of the HY2_Receiver is assessed based on indicators such as the multipath effect, ionospheric delay, cycle slip and data utilization, and assessments have suggested that the receiver can be used in precise orbit determination (POD) missions involving low-Earth-orbit (LEO) satellites. In this study, satellite-borne GPS data are used for POD with a reduced-dynamic (RD) method. Phase centre offset (PCO) and phase centre variation (PCV) models of the GPS antenna are established during POD, and their influence on the accuracy of orbit determination is analysed. After using the PCO and PCV models in POD, the root mean square (RMS) of the carrier-phase residuals is around 0.008 m and the orbit overlap validation accuracy in each direction reaches approximately 0.01 m. Compared with the precise science orbit (PSO) provided by the Centre National d’Etudes Spatiales (CNES), the RD orbit accuracy of HY-2C in the radial (R) direction reaches 0.01 m. The accuracy of satellite laser ranging (SLR) range validation is better than 0.03 m. Additionally, a new method is proposed to verify the accuracy of the RD orbit of HY-2C by using space-borne Doppler orbitography and radiopositioning integrated by satellite (DORIS) data directly. DORIS data are directly compared to the result calculated using the accurate coordinates of beacons and the RD orbit, and the results indicate that the external validation of HY-2C RD orbit has a range rate accuracy of within 0.0063 m/s.

Highlights

IntroductionThe Haiyang-2C (HY-2C) satellite was successfully launched on 21 September 2020; it was the third satellite launched by China to monitor the dynamic marine environment and the second satellite in the marine dynamic satellite series established as part of China’s national civil space infrastructure [1]
The overlap method is applied to assess the accuracy of orbit determination, and the detailed overlap analysis suggests that the root mean square (RMS) value of the residual of overlapping orbits is 0.006 m in the R direction, 0.011 m in the T direction, and 0.006 m in the N direction
The internal-coincidence accuracy-verification results indicate that the HY-2C satellite orbit determination strategy is reliable; notably, the error term is eliminated during the precise orbit determination (POD)

Summary

Introduction

The Haiyang-2C (HY-2C) satellite was successfully launched on 21 September 2020; it was the third satellite launched by China to monitor the dynamic marine environment and the second satellite in the marine dynamic satellite series established as part of China’s national civil space infrastructure [1]. The main goal is to obtain high-precision and highresolution real-time observations of the ocean, such as the sea surface height and significant wave height [2]. The mass of HY-2C is 1677 kg, the Semi major axis is 7328.583 km, the Eccentricity is 0.000012, the average height is 957 km at an inclination of 66◦ , and the Remote Sens. The satellite is connected to HY-2B and HY-2D to form an all-weather, high-frequency, global, marine dynamic environment-monitoring system that covers large and medium scales

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