<h2>AAS  96-124</h2><h2>EARTH GRAVITATIONAL ERROR BUDGET</h2><h4>W. N. Barker, S. J. Casali, and R. N. Wallner, Kaman Sciences Corporation</h4><h2> Abstract </h2>The primary objective of this study was to estimate an Earth gravitational model error budget using orbits representative of the CMAS (Cheyenne Mountain Air Station) space surveillance catalog.  To meet this objective, two main techniques were employed:  First, simulations were conducted that only considered geopotential perturbations in an effort to isolate and quantify truncation errors.  Second, actual satellites and real Space Surveillance Network (SSN) observations were analyzed in an operational context, considering both orbit determination and prediction.  The geopotential models studied were World Geodetic System 1972 (WGS-72), WGS-84, and the NASA Joint Gravity Model 2 (JGM2).<br><br>