Preliminary orbit determination of a tethered satellite

Interest in the deployment of tethered satellites has led to a need for preliminary orbit determination methods which are capable of distinguishing tethered satellites from untethered ones. Classical preliminary orbit determination methods, which are used for Keplerian satellites, generally require two or more position vectors along with their respective observation times in order to determine a preliminary orbital element set. These conventional methods, however, are unable to distinguish between Keplerian and tethered satellites, whose motion is modified due to the presence of a tether force. The use of conventional methods result in the calculation of inaccurate orbital elements if the observed satellite is part of a tethered satellite system. Modifications have been made to four classical preliminary orbit determination methods in order to allow for the identification of tethered satellites. These modifications provide the ability to distinguish between a tethered satellite and an untethered one. This paper applies these modified preliminary orbit determination methods to the problem of the identification of a tethered satellite. The performance of these methods is evaluated through scenarios of differing tether lengths and levels of observation error, and results are compared in order to determine the most accurate method.