Transponder delay effect in light time calculations for deep space navigation

TL;DR

This paper examines how traditional approximations in light time calculations can neglect small but significant effects like transponder delay, impacting deep space navigation accuracy, especially during Earth flybys.

Contribution

It proposes an improved method for light time calculation that accounts for transponder delay effects in deep space navigation.

Findings

Traditional models neglect transponder delay effects.

Improved calculations can enhance orbit determination accuracy.

Effects are significant during specific configurations like Earth flybys.

Abstract

During the last decade, the precision in the tracking of spacecraft has constantly improved. The discovery of few astrometric anomalies, such as the Pioneer and Earth flyby anomalies, stimulated further analysis of the operative modeling currently adopted in Deep Space Navigation (DSN). Our study shows that some traditional approximations lead to neglect tiny terms that could have consequences in the orbit determination of a probe in specific configurations such as during an Earth flyby. Therefore, we suggest here a way to improve the light time calculation used for probe tracking.