The signals from the Cassini spacecraft that will be affected by delay fluctuations in the Earth's atmosphere. These fluctuations are dominated by water vapor in the troposphere, and in the case of Gravitaional Wave Experiment (GWE), they are likely to be a limiting error source. A passive remote sensing system, centered around a water vapor radiometer (WVR), has been developed to provide calibrations of water vapor fluctuations during radio science experiments.

Cassini Cassini radio GWE gravity wave experiment ↗

NASA NTRS1996

Atmospheric Calibration for Cassini Radio Science

Explore the source record for details and available documents.

GWE gravitational wave experiment Cassini microwav↗

NASA NTRS1995

Strategies for Near Real Time Estimates of Precipitable Water Vapor from GPS Ground Receivers

GPS-based estimates of precipitable water vapor (PWV) may be useful in numerical weather models to improve short-term weather predictions. To be effective in numerical weather prediction models, GPS PWV estimates must be produced with sufficient accuracy in near real time. Several estimation strategies for the near real time processing of GPS data are investigated.

GPS↗

NASA NTRS1993

Velocity Estimation of a Wind-Driven Martian Balloon

The Mars '96 mission will place a balloon probe into the atmosphere of Mars.

altimeter↗

NASA NTRS1993

Velocity Estimation of a Wind Driven Martian Balloon

Balloon borne instruments have long been used to measure the properties of the Earth's atmosphere.

three↗

NASA NTRS1993

Very-Long-Baseline-Interferometry Measurements of Planetary Orbiters at Mars and Venus

Very-long-baseline interferometric measurements of the positions of planetary orbiters/landers relative to nearby extra galactic radio sources provide information on the positions of the planets in the inertial reference frame described by the measured positions of the radio sources.

very-long-baseline↗

NASA NTRS1990

GPS measurements of regional deformation in southern California - Some constraints on performance

Results from the first major survey of southern California with GPS equipment are presented along with some limited results from late experiments assessing GPS performance by analysis of day-to-day and longer-term repeatability, as well as comparisons with VLBI. GPS performance on longer (50-500 km or longer) baselines, a length range useful for measurement of regional deformation and fault block velocities, is emphasized. The implications of this level of performance for meeting longer-term scientific objectives is addressed. It is concluded that GPS techniques and yield results comparable to those achieved with mobile VLBI techniques in California, assuming that appropriate network design and analysis techniques are used. GPS can thus provide important constraints on regional deformation in California with five yrs or less of measurements.

Dixon, T.↗