Accession Number:

ADA010424

Title:

An Updated Empirical Density Model for Predicting Low-Altitude Satellite Ephemerides.

Descriptive Note:

Air Force surveys in geophysics,

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS HANSCOM AFB MASS

Personal Author(s):

• Garrett,Henry B.

Report Date:

1975-03-19

Pagination or Media Count:

23.0

Abstract:

Two empirical density models based on drag analyses of 22 low-perigee satellites are developed for use in predicting low-altitude satellite ephemerides. A stepwise multiple regression analysis is performed with density at 145 km as the dependent variable, and a number of independent variables chosen to represent variations with solar cycle, geomagnetic activity, latitude, season, day of the year, and time of day. Densities between 120 and 500 km are determined from the hydrostatic law in a simple but physically realistic analytic form. The two models compare very well with the 1971 Jacchia model. The main advantage of such models is that they represent a major savings in both computer storage and run time making possible improvements in operational systems.

Descriptors:

• *ATMOSPHERE MODELS
• *ATMOSPHERIC DENSITY
• *UPPER ATMOSPHERE
• COMPUTER PROGRAMS
• FORTRAN
• ARTIFICIAL SATELLITES
• PERIODIC VARIATIONS
• EPHEMERIDES

Subject Categories:

• Atmospheric Physics
• Spacecraft Trajectories and Reentry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE