Wyniki wyszukiwania - BazTech

1

Satellite Laser Ranging technique as a tool for the determination of the Schwarzschild, de Sitter and Lense-Thirring effects

Matyszewski Mateusz, Lejba Paweł, Jagoda Marcin, Tysiąc Paweł

Reports on Geodesy and Geoinformatics

|

2023

|

Vol. 116

77--84

EN

Satellite Laser Ranging (SLR) is a modern technique used in various research areas and applications related to geodesy and geodynamics. It is commonly used for tasks such as establishing the International Terrestrial Reference Frame (ITRF), monitoring Earth Orientation Parameters (EOP), determining the geocenter, measuring fundamental physical constants, calibrating microwave tracking techniques, conducting time transfer experiments, and studying gravitational and general relativistic effects. Laser measurements of the LARES and LAGEOS satellites are used to determine the relativistic effects acting on these satellites. The objective of the present research is to analyze the perturbing forces of relativistic origin (Schwarzschild, de Sitter and Lense-Thirring effects) acting on the LARES, LAGEOS-1 and LAGEOS-2 satellites. By using data from fifteen SLR measurement stations, the precise orbits of these satellites were determined over a span of 840 hours using the GEODYN II orbital software package. The calculation process used a set of procedures, models of forces, and constants that are currently recommended by the International Earth Rotation and Reference Systems Service (IERS) and the International Laser Ranging Service (ILRS). Based on the precise orbits of the LARES, LAGEOS-1, and LAGEOS-2 satellites, calculations were made to determine the values of relativistic accelerations acting on these satellites. These values oscillate with a period equal to half of the orbital period for the de Sitter and Lense-Thirring effects, and a quarter of the orbital period for the Schwarzschild effect.

2

Centimeter-level precise orbit determination for the HY-2A satellite using DORIS and SLR tracking data

Kong Q., Guo J., Sun Y., Zhao Ch., Chen Ch.

Acta Geophysica

|

2017

|

Vol. 65, no. 1

1--12

EN

The HY-2A satellite is the first ocean dynamic environment monitoring satellite of China. Centimeter-level radial accuracy is a fundamental requirement for its scientific research and applications. To achieve this goal, we designed the strategies of precise orbit determination (POD) in detail. To achieve the relative optimal orbit for HY-2A, we carried out POD using DORIS-only, SLR-only, and DORIS + SLR tracking data, respectively. POD tests demonstrated that the consistency level of DORIS-only and SLR-only orbits with respect to the CNES orbits were about 1.81 cm and 3.34 cm in radial direction in the dynamic sense, respectively. We designed 6 cases of different weight combinations for DORIS and SLR data, and found that the optimal relative weight group was 0.2 mm/s for DORIS and 15.0 cm for SLR, and RMS of orbit differences with respect to the CNES orbits in radial direction and three-dimensional (3D) were 1.37 cm and 5.87 cm, respectively. These tests indicated that the relative radial and 3D accuracies computed using DORIS + SLR data with the optimal relative weight set were obviously higher than those computed using DORIS-only and SLR-only data, and satisfied the requirement of designed precision. The POD for HY-2A will provide the invaluable experience for the following HY-2B, HY-2C, and HY-2D satellites.

3

On precise orbit determination of HY-2 with space geodetic techniques

Guo J., Kong Q., Qin J., Sun Y.

Acta Geophysica

|

2013

|

Vol. 61, no. 3

752--772

EN

As the first radar altimetric satellite of China, HY-2 requires the precise orbit determination with a higher accuracy than that of other satellites. In order to achieve the designed radial orbit with the accuracy better than 10 cm for HY-2, the methods of precise orbit determination for HY-2 with the centimeter-level accuracy based on space geodetic techniques (DORIS, SLR, and satellite-borne GPS) are studied in this paper. Perturbations on HY-2 orbit are analyzed, in particular those due to the non-spherical gravitation of the earth, ocean tide, solid earth tide, solar and earth radiation, and atmospheric drag. Space geodetic data of HY-2 are simulated with the designed HY-2 orbit parameters based on the orbit dynamics theory to optimize the approaches and strategies of precise orbit determination of HY-2 with the dynamic and reduced-dynamic methods, respectively. Different methods based on different techniques are analyzed and compared. The experiment results show that the nonspherical perturbation modeled by GGM02C causes a maximum perturbation, and errors caused by the imperfect modeling of atmospheric drag have an increasing trend on T direction, but errors are relatively stable on the other two directions; besides, the methods with three space geodetic techniques achieve the radial orbit with the precision better than 10 cm.