Exploitation of the Potential of the SLR-tracked altimetry and GNSS satellites for determination of global geodetic parameters (PotS)

该项目的主要目标是研究和开发利用SLR跟踪的非球面测高和全球导航卫星系统（GNSS）卫星扩展常用的四颗球形卫星卫星激光测距（SLR）星座的潜力，以精确和一致地确定全球大地测量参数。这些参数是全球观测网中单反站的坐标，即地球参考系（TRF）、TRF的原点和尺度、地球自转参数（ERP）和地球时变重力场的长波长系数。考虑到两组非球形卫星，即测高卫星和全球导航卫星系统卫星，该项目超越了其他研究，这些研究的主要重点是开发球形（大地测量）卫星的完整星座。此外，我们将研究不同单反跟踪卫星星座的能力（特定非球形卫星的影响），并结合多普勒轨道和卫星集成无线电定位（DORIS）跟踪卫星，以提高上述全球大地测量参数组的精度、一致性和稳定性。通过在不同时间、高度和倾角对选定的绕地球轨道运行的测高卫星和GNSS卫星进行观测，使用显著增加的观测数量，将减少估计大地测量参数之间的相关性，并减少估计参数的误差。在这个项目的执行过程中，将回答以下研究问题：1。灵敏度：全球大地测量参数对每个特定卫星（或卫星群）的单反观测有多敏感？2. 精度：与传统的四颗卫星设置相比，从单反观测分析到最佳多卫星（测高、GNSS、它们的组合、LAGEOS-1/2和Etalon-1/2）解决方案，全球大地测量参数的确定和去相关的精度如何？3. 参数化：实现全球大地测量参数最高精度和稳定性的最佳轨道参数化是什么？4. 一体化：在由选定的球面单反、测高和GNSS卫星组成的多卫星解决方案中，对多丽丝和单反观测进行综合处理以确定全球大地测量参数的好处是什么？5. 未来：未来单反跟踪卫星对全球大地测量参数的影响是什么？扩展的空间段应该如何设计？如何扩展单反地面部分，以提供更强大和准确的解决方案？

The main objective of this project is to investigate and exploit the potential of extending the commonly used four spherical satellite Satellite Laser Ranging (SLR) constellation by SLR-tracked non-spherical altimetry and Global Navigation Satellite System (GNSS) satellites to precisely and consistently determine global geodetic parameters. Such parameters are the coordinates of SLR stations in the global observation network, i.e., the Terrestrial Reference Frame (TRF), the origin and the scale of the TRF, Earth Rotation Parameters (ERP) and long-wavelength coefficients of the Earth’s time-variable gravity field. Taking into account two groups of non-spherical satellites, the altimetry and the GNSS satellites, this project goes beyond other studies that put their main focus on exploiting the full constellation of spherical (geodetic) satellites. Moreover, we will investigate the capability of different SLR-tracked satellite constellations (impact of specific non-spherical satellites), also in combination with Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS)-tracked satellites, to improve the above-mentioned global geodetic parameter groups in terms of accuracy, consistency and stability over time. Using a significantly increased number of observations by including observations to selected altimetry and GNSS satellites orbiting the Earth at various times, altitudes and inclinations will reduce the correlations between the estimated geodetic parameters and reduce errors of the estimated parameters. During the execution of this project, the following research questions will be answered: 1. Sensitivity: How sensitive are the global geodetic parameters to the SLR observations of each specific satellite (or groups of satellites)? 2. Precision: How precisely can the global geodetic parameters be determined and de-correlated from the analysis of SLR observations to the optimal multi-satellite (altimetry, GNSS, a combination of them, LAGEOS-1/2, and Etalon-1/2) solution compared to the conventional four-satellite setup? 3. Parameterization: What is the optimal orbit parameterization to achieve highest accuracy and stability of the global geodetic parameters? 4. Integration: What is the benefit of the integrated processing of DORIS and SLR observations in a multi-satellite solution comprising selected spherical SLR, altimetry and GNSS satellites for the determination of the global geodetic parameters? 5. Future: What is the impact of future SLR-tracked satellites on the global geodetic parameters? How should an extended space segment be designed? How can the SLR ground segment be extended to provide even more robust and accurate solutions?