Improving station pointing alignment for SLR using approaches based on TLEs and real-time measurements

Space safety is becoming an increasingly important topic for our society, in particular with respect to space debris. According to the ESA's Space Environment Report 2025, the number of satellites, and, consequently the amount of space debris, particularly in low Earth orbits (LEOs) is growing rapidly. To ensure that satellite operators are informed about the need for evasive manoeuvres, it is necessary to implement countermeasures such as the identification and monitoring of space debris. Knowing the approximate positions of space objects to be tracked via Satellite Laser Ranging (SLR) is essential for aligning the SLR station's pointing accordingly. Accurate orbit predictions for satellites are provided to the stations by prediction centres. But this does not apply to space debris. Instead, the so-called two-line elements (TLEs) are used to predict the orbits of these objects. TLEs contain important orbital elements which are related to position and velocity of the space object at a specific time or point. However, they are limited in their accuracy which results in inaccurate orbit predictions. To achieve a more precise laser alignment for space debris tracking, we present an approach to improve the accuracy of orbit predictions based on TLEs, using the SLR functionality of the GROOPS (Gravity Recovery Object Oriented Programming System) software toolkit. Furthermore, we demonstrate that incorporating real-time measurements can enhance the accuracy of orbit predictions for station pointing alignment in subsequent passes.