Astrometry of Cassini with the VLBA to Improve the Saturn Ephemeris

Abstract

Planetary ephemerides have been developed and improved over centuries. They are a fundamental tool for understanding solar system dynamics, and essential for planetary and small body mass determinations, occultation predictions, high-precision tests of general relativity, pulsar timing, and interplanetary spacecraft navigation. This paper presents recent results from a continuing program of high-precision astrometric very-long-baseline interferometry (VLBI) observations of the Cassini spacecraft orbiting Saturn, using the Very Long Baseline Array (VLBA). We have previously shown that VLBA measurements can be combined with spacecraft orbit determinations from Doppler and range tracking and VLBI links to the inertial extragalactic reference frame (ICRF) to provide the most accurate barycentric positions currently available for Saturn. Here we report an additional five years of VLBA observations along with improved phase reference source positions, resulting in an improvement in residuals with respect to the Jet Propulsion Laboratory's dynamical ephemeris.

Accepted for publication in the Astronomical Journal

References in corpus (2)

• DiFX: A software correlator for very long baseline interferometry using multi-processor computing environments
• Spacecraft VLBI and Doppler tracking: algorithms and implementation

Cited by in corpus (5)

• On the contribution of PRIDE-JUICE to Jovian system ephemerides
• Role of lunar laser ranging in realization of terrestrial, lunar, and ephemeris reference frames
• Gaia-DR2 asteroid observations and INPOP planetary ephemerides
• Systematics of planetary ephemeris reference frames inferred from pulsar timing astrometry
• COMPASS: VLBI Beacons In Support of Lunar Science and Exploration