Performance Analysis of Ranging Techniques for the KPLO Mission

Abstract

In this study, the performance of ranging techniques for the Korea Pathfinder Lunar Orbiter (KPLO) space communication system is investigated. KPLO is the first lunar mission of Korea, and pseudo-noise (PN) ranging will be used to support the mission along with sequential ranging. We compared the performance of both ranging techniques using the criteria of accuracy, acquisition probability, and measurement time. First, we investigated the end-to-end accuracy error of a ranging technique incorporating all sources of errors such as from ground stations and the spacecraft communication system. This study demonstrates that increasing the clock frequency of the ranging system is not required when the dominant factor of accuracy error is independent of the thermal noise of the ranging technique being used in the system. Based on the understanding of ranging accuracy, the measurement time of PN and sequential ranging are further investigated and compared, while both techniques satisfied the accuracy and acquisition requirements. We demonstrated that PN ranging performed better than sequential ranging in the signal-to-noise ratio (SNR) regime where KPLO will be operating, and we found that the T2B (weighted-voting balanced Tausworthe, voting v = 2) code is the best choice among the PN codes available for the KPLO mission.

Observational Arc-Length Effect on Orbit Determination for Korea Pathfinder Lunar Orbiter in the Earth-Moon Transfer Phase Using a Sequential Estimation

“…The measurement error statistics were accounted for by using the specifications of the KDSA hardware and the values of the DNS service catalog for the tracking data simulation (JPL 2015). Additionally, we used the performance analysis results for the KPLO communication and tracking obtained through sequential and PN ranging techniques (Park & Moon 2018). In order to considering the transponder delay variation uncertainty and the tracking accuracy, the ranging noises of the DSN and KDSA were set to 13 m and 22 m, respectively.…”

Observational Arc-Length Effect on Orbit Determination for KPLO Using a Sequential Estimation Technique

“…range and Doppler were employed for KPLO measurement simulation Park & Moon (2018). analyzed the performance of both ranging techniques (sequential and PN ranging) for the KPLO space communication and demonstrated that PN ranging has better performance than sequential ranging forKPLO communication and operation.…”