Detector-specific issues in Satellite Laser Ranging to Swarm-A/B/C satellites
Dariusz Strugarek, Krzysztof Sośnica, Radosław Zajdel, Grzegorz Bury
Abstract
Satellite Laser Ranging (SLR) to Low Earth Orbiters (LEOs) is traditionally used to validate orbits derived by microwave techniques, e.g., Global Positioning System (GPS). For most LEOs, SLR is the only possibility to independently assess the GPS orbit quality, to calibrate onboard instruments, and to reveal otherwise unnoticed systematic errors. However, the detector-specific errors in SLR measurements may corrupt the SLR observations and derived parameters. We found that the stations employing Compensated Single-Photon Avalanche Diode (CSPAD) detectors are characterized by the lowest, 15 and 21 mm root-mean-square residuals for reduced-dynamic and kinematic orbits, respectively, and show almost no dependency on the satellite nadir angle nor the observation acquisition time, as opposed to stations with Multi-Channel Plates (MCP) and Photomultiplier Tube (PMT) detectors. SLR observations to Swarm-A/B/C can also be used for the determination of SLR station coordinates characterized by 27, 15, 18 mm interquartile range repeatability for the Up, North, and East components, respectively.