# Active Control Loop of the BOROWIEC SLR Space Debris Tracking System
## 5 Conclusions  
The process of the laser ranging measurement of orbital objects with the uncertain ephemerides is a difficult issue. Besides, the growing amount of space debris forces the use of new solutions to maximize information about the orbits of such objects. The available number of laser tracking sensors is too small to improve the quality of the orbits obtained from radar survey sensors. This paper proposed solutions to improve the effectiveness of measuring the distance to the orbital objects with uncertain orbits using the active control loop implemented at the Borowiec SLR station. The presented algorithms for the active correction of mount motion control and automatic object search functionality led to an increase in the effectiveness of measuring objects such as space debris. Cooperative objects are only a small subset of the space debris population, so these objects should be treated as uncooperative targets in terms of the measurements based on the TLE ephemeris. An  
Figure 11: Correction of the telescope axis motion based on the modified Archimedean spiral.  
additional advantage of these solutions is the ability to perform measurements in automatic mode, which with 24/7 operations relieves the need for the SLR station operator. Further research is needed to optimize the proposed solutions, which depend on the type of object and the orbital regime. Depending on the capabilities of a given laser station, it is possible to carry out detailed analyses with the implementation of the described algorithms. The proposed analyses may refer to the detection of the coordinate offset values of a specific orbital object on the basis of information stored in the database. Such information can be gathered from previous observations of an orbital object using the photon event active control loop or passive optical acquisition active control loop algorithms. The obtained and averaged value of the positional offset stored in the database may be the starting point to perform a new observation of the given orbital object. The analysis can be made taking into account the type of ephemerides (TLE, CPF), the orbital altitude, as well as the suitability of ephemeris use depending on the epoch of its generation. Another aspect that can be investigated is the analysis of the required beam divergence in order to find the object in the initial phase. Such an analysis can be performed for object types (e.g., rocket bodies), as well as individually for a specific orbital object. Furthermore, a quantitative statistic of photon events for a specific object can be made. In this way, it will be possible to determine the effectiveness of subsequent observations during the target search process. A separate issue is the parameterization of algorithms, which depends on the specific configuration of the laser sensor. The parameters of the receiving telescope, including the photon detector, and the telescope mount motion control loop are of importance here. Commissioning of the second SLR system at Borowiec Astrogeodynamic Observatory based on a dedicated laser and photon detector will allow for many analyses taking into account the impact of ephemeris uncertainty on the reaction time of the SLR system and the obtained results. Optimizing the operation of algorithms during daytime observations is not without significance, which will be the next stage of the research. The effectiveness of the proposed solutions can be verified only in the conditions of the availability of a measuring laser and a photon detector. Only in this way, by obtaining the reflections from the orbital object, will it be possible to determine the effectiveness of the operating algorithms.  
This research received no external funding.  
Not applicable.  
The author declares no conflict of interest.