Precise interferometric tracking of spacecraft at low sun-earth-probe anglesWhen a spacecraft is at low sun-earth-probe (SEP) angle, phase perturbations induced in the spacecraft's signal by the solar plasma can impede the acquisition of meaningful spacecraft Very Long Baseline Interferometry (VLBI) measurements. This phenomenon imposes limitations on our ability to successfully acquire the spacecraft signal, and also introduces unmodeled errors into data that are successfully acquired. In this paper, an analysis of the solar plasma induced error on interferometric delay rate as a function of SEP angle is performed. In addition, the probability of correct signal phase connection as a function of SEP angle and plasma variability is calculated for 2.3 GHz and 8.4 GHz signals. In December 1986, an experiment was conducted to demonstrate VLBI navigation at low SEP angles, using the Voyager 2 spacecraft. The results of this experiment are consistent with the conclusions reached in the low SEP analysis and are also consistent with a theoretical error model for water vapor fluctuations in the earth's troposphere.
Document ID
19880035204
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Kahn, Robert D. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Border, James S. (California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1988
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking