Accurate Ground-based Near-Earth-Asteroid Astrometry using Synthetic Tracking

TL;DR

This paper demonstrates 10 milliarcsecond astrometric precision for near-Earth asteroids using synthetic tracking with short exposures, improving orbit determination and potential spacecraft navigation accuracy.

Contribution

It introduces synthetic tracking for ground-based NEA astrometry, achieving higher precision than traditional long-exposure methods, and discusses future improvements with Gaia data.

Findings

Achieved 10 mas astrometric precision on NEAs.

Synthetic tracking reduces trailing loss and atmospheric jitter effects.

Potential for ground-based asteroid navigation using optical communication.

Abstract

Accurate astrometry is crucial for determining orbits of near-Earth-asteroids (NEAs) and therefore better tracking them. This paper reports on a demonstration of 10 milliarcsecond-level astrometric precision on a dozen NEAs using the Pomona College 40 inch telescope, at the JPL's Table Mountain Facility. We used the technique of synthetic tracking, in which many short exposure (1 second) images are acquired and then combined in post-processing to track both target asteroid and reference stars across the field of view. This technique avoids the trailing loss and keeps the jitter effects from atmosphere and telescope pointing common between the asteroid and reference stars, resulting in higher astrometric precision than the 100 mas level astrometry from traditional approach of using long exposure images. Treating our synthetic tracking of near-Earth asteroids as a proxy for observations of future spacecraft while they are downlinking data via their high rate optical communication laser beams, our approach shows precision plane-of-sky measurements can be obtained by the optical ground terminals for navigation. We also discuss how future data releases from the Gaia mission can improve our results.