Speaker
Description
Laser technologies play a key role in modern space exploration, providing highly accurate determination of the orbit of artificial Earth satellites (ESAs), navigation and data transmission. The main method used is satellite laser ranging (SLR), which allows measuring distances to satellites with an accuracy of a few millimeters. The range of tasks solved using satellite laser ranging, and hence location, is extremely wide, covering all aspects of space geodesy. In addition, it is the only measurement method that allows direct determination of the coordinates of the geocenter of the universal terrestrial coordinate system.
The accuracy of laser location largely depends on the accuracy of the model used to account for tropospheric delay, which consists of zenith delay and a scaling function that takes into account the angle of elevation above the horizon. In addition, it has been established that relativistic effects are observed in laser location of satellites, affecting the accuracy of observations. One of the main effects that complicate location is the velocity aberration, as a result of which the center of the spot of the reflected laser signal turns out to be distant from the location of the laser station. This, together with the fact that the luminous flux of the reflected pulse decreases greatly from the center to the periphery, causes a significant weakening of the intensity of the reflected signal. This fact makes it difficult to register the reflected signal and creates uncertainty in determining the exact distances, and hence the coordinates of the satellite. There is also a difference in the location of the reflected signal at the level of the Earth's surface and the receiving telescope depending on the type of satellite orbit - circular or elliptical.
The report analyzes the methods used to increase the amount of light energy falling on the lens of the receiving telescope. A comparative analysis is made of the advantages and disadvantages of a specially designed electro-mechanical coordinate device to compensate for relativistic effects affecting the accuracy of observations for satellites in circular and elliptical orbits. It is shown that the distance between the laser emitter and the receiving telescope should not be greater than 1 km for satellites in circular orbit, with the speed of movement of the receiving telescope in the range of 1 - 10 km/h.
Data are presented for satellites moving in elliptical orbits, for which the use of an electro-mechanical coordinate system requires a real-time numerical modeling process. The model should also include a study of the effectiveness of laser location for elliptical satellite orbits with different initial parameters and eccentricity.
Keywords: Satellite Laser Ranging, satellite orbits, orbit optimization, numerical modeling, relativistic effects