In the last decade, the requirements of data volume in satellite communication increased significantly. End-to-end data transmission between high-orbit satellites and ground segments is constrained by bottlenecks such as limited frequency resources and low transmission rates, making it imperative to optimize TCP implementation. In this article, five mainstream data transmission schemes were evaluated: double-side TCP lightweight parameter optimization scheme, double-side TCP heavyweight core optimization scheme, ground-side single-side TCP heavyweight core optimization scheme, heavyweight tunnel optimization scheme and lightweight TCP-QUIC proxy optimization scheme. Through in-depth analysis, the lightweight TCP-QUIC proxy outperformed other schemes in reducing the delay of connection establishment, improving the efficiency of congestion control and flow control, and supporting multi-channel multiplexing and connection migration. Validated using a prototype system developed by the Beijing Institute of Computer Technology and Application, hardware-in-the-loop simulations show that the optimized scheme achieves significant performance gains: the 150 Mbps downlink transmission rate is improved by 100 times, while the 10 Mbps uplink transmission rate is enhanced by 7 times. These optimized rates fully satisfy user requirements. This study demonstrates that the proposed lightweight TCP-QUIC proxy-based scheme is a strong candidate for standardizing data transmission protocols in China’s future high-orbit satellite missions.

In early 2025, the Jason-3 satellite orbit was maneuvered from the "interleaved" orbit to a tandem configuration with the Sentinel-6A satellite, concurrent with the upgrade of its Geophysical Data Records (GDR) from Version F to G. To date, six complete cycles of GDR-G products have been released, featuring notable improvements such as the official replacement of the MLE3 retracker with the Adaptive retracker for Sea Surface Height Anomaly (SSHA) calculations. This study aims to evaluate GDR-G performance by analyzing SSHA under eight error correction strategies, using the last six GDR-F cycles and first six GDR-G cycles. Key findings include: significantly reduced SSHA noise in GDR-G compared to GDR-F; relative biases of up to ~4 cm in sea surface height when using different retracking algorithms or correction strategies; and optimal accuracy achieved with the Adaptive retracker combined with 3D sea state bias (SSB) correction. Comparative analysis of Significant Wave Height (SWH), backscattering coefficient (Sigma-0), and wind speed (WS) between MLE4 and Adaptive retrackers revealed anomalies in Adaptive results: clustered SWH outliers near 0 m and 4 m, and WS outliers slightly above 28 m/s. These anomalies, linked to invalid MLE4 retracking results and non-Brownian echo shapes (coastal/inland waters, sea ice), suggest that refining the Adaptive retracker or developing new algorithms could further enhance Jason-3’s observational performance.