Mars gravity field error analysis from simulated radio tracking of Mars Observer

Conference · Thu Aug 30 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

OSTI ID:5385073

Smith, D E; Lerch, F J ^[1]; Chan, J C; Chinn, D S; Iz, H B; Mallama, A; Patel, G B ^[2]

---

1. NASA Goddard Space Flight Center, Greenbelt, MD (USA)
2. ST Systems Corporation, Lanham, MD (USA)

The Mars Observer (MO) Mission, in a near-polar orbit at 360-410 km altitude for nearly a 2-year observing period, will greatly improve our understanding of the geophysics of Mars, including its gravity field. To assess the expected improvement of the gravity field, the authors have conducted an error analysis based upon the mission plan for the Mars Observer radio tracking data from the Deep Space Network. Their results indicate that it should be possible to obtain a high-resolution model (spherical harmonics complete to degree and order 50 corresponding to a 200-km horizontal resolution) for the gravitational field of the planet. This model, in combination with topography from MO altimetry, should provide for an improved determination of the broad scale density structure and stress state of the Martian crust and upper mantle. The mathematical model for the error analysis is based on the representation of doppler tracking data as a function of the Martian gravity field in spherical harmonics, solar radiation pressure, atmospheric drag, angular momentum desaturation residual acceleration (AMDRA) effects, tracking station biases, and the MO orbit parameters. Two approaches are employed. In the first case, the error covariance matrix of the gravity model is estimated including the effects from all the nongravitational parameters (noise-only case). In the second case, the gravity recovery error is computed as above but includes unmodelled systematic effects from atmospheric drag, AMDRA, and solar radiation pressure (biased case). The error spectrum of gravity shows an order of magnitude of improvement over current knowledge based on doppler data precision from a single station of 0.3 mm s{sup {minus}1} noise for 1-min integration intervals during three 60-day periods.

• OSTI ID: 5385073
• Report Number(s): CONF-9001119--
• Conference Information: Journal Name: Journal of Geophysical Research; (United States) Journal Volume: 95:B9
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CORRELATIONS
DATA ACQUISITION
DENSITY
DRAG
ERRORS
GEOPHYSICS
GRAVITATIONAL FIELDS
MARS PLANET
MATHEMATICAL MODELS
PHYSICAL PROPERTIES
PLANETARY ATMOSPHERES
PLANETS
RADIATION PRESSURE
RADIATIONS
SATELLITES
SOLAR RADIATION
STELLAR RADIATION
TOPOGRAPHY