The GENESIS mission prepared for launch in 2027 integrates the four space-geodetic techniques on a single spaceborne platform in medium Earth orbit. With its unique observations and alternative tie concepts, the mission aims to contribute to an improved accuracy and homogeneity of future terrestrial reference system realizations. To assess the expected contribution of Global Navigation Satellite System (GNSS) tracking, a comprehensive GNSS coverage analysis is performed based on detailed link-budget simulations, taking into account the best available gain patterns and signal-specific transmit power estimates derived for this work from measurements of a high-gain dish antenna. The benefit of different receiver antenna concepts for the GENESIS spacecraft is assessed, and it is demonstrated that a single-antenna system with either a nadir-looking or side-looking boresight is a viable alternative to the dual-antenna configuration considered in initial mission studies. Compared to terrestrial users and missions in low Earth orbit, GENESIS will collect GNSS signals transmitted at up to two times larger off-boresight angles. Only limited information on the actual transmit antenna phase patterns is presently available in this region, which hampers a quantitative assessment of the expected measurement and orbit determination accuracy. As such, a comprehensive release of manufacturer calibrations is encouraged for all blocks of GPS and Galileo satellites. In parallel, a need for in-flight characterization and calibration of the GNSS transmit antennas for off-boresight angles of up to \(30^\circ \) using observations of the GENESIS mission itself is expected. The impact of such calibrations on the overall quality of terrestrial reference frame parameters will need to be assessed in comprehensive simulations of global GNSS network solutions with joint processing of terrestrial and GENESIS GNSS observations.

准备于 2027 年发射的 GENESIS 任务将四种空间大地测量技术集成到中地球轨道的单个星载平台上。凭借其独特的观测结果和替代的联系概念，该任务旨在提高未来地面参考系统实现的准确性和同质性。为了评估全球导航卫星系统 (GNSS) 跟踪的预期贡献，基于详细的链路预算模拟进行了全面的 GNSS 覆盖分析，同时考虑了最佳可用增益模式和针对这项工作得出的特定信号发射功率估计高增益碟形天线的测量。评估了 GENESIS 航天器不同接收器天线概念的好处，并证明具有天底视轴或侧视视轴的单天线系统是初始任务研究中考虑的双天线配置的可行替代方案。与地面用户和近地轨道任务相比，GENESIS 将收集以两倍大的离轴角传输的 GNSS 信号。目前该区域仅提供有关实际发射天线相位图的有限信息，这妨碍了对预期测量和轨道确定精度的定量评估。因此，鼓励对所有 GPS 和伽利略卫星块进行制造商校准的全面发布。与此同时，预计需要使用 GENESIS 任务本身的观测结果对 GNSS 发射天线进行飞行中表征和校准，以获得高达\(30^\circ \)的离轴角。此类校准对地面参考系参数整体质量的影响需要在全球 GNSS 网络解决方案的综合模拟中进行评估，并联合处理地面和 GENESIS GNSS 观测结果。