Accession Number : ADA263897

Title :   Lambert Algorithm Including Drag.

Descriptive Note : Final rept.,

Corporate Author : NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA

Personal Author(s) : Lawton, J. A.

Report Date : JAN 1992

Pagination or Media Count : 22

Abstract : An algorithm is developed that solves Lambert's problem when a vehicle encounters drag. For an environment of low to moderate atmospheric density, Lambert's solution is obtained by linearizing about a reference Keplerian trajectory. This linearization process requires no numerical ordinary differential equation solution techniques and, as such, is computationally efficient. For flight through a region of higher atmospheric density, or if greater accuracy is required, an iterative technique is used that starts with the linearized solution and does a quasi-Newton iteration process with an analytic initial approximation to the Jacobian. For subsequent iterations, the Jacobian estimate is updated using Broyden's update. The resulting algorithm converges superlinearly.... Algorithm, Lambert's problem, Drag, Trajectory.

Descriptors :   *ALGORITHMS, *ATMOSPHERIC DENSITY, *AERODYNAMIC DRAG, ACCURACY, DIFFERENTIAL EQUATIONS, ENVIRONMENTS, ESTIMATES, FLIGHT, ITERATIONS, TRAJECTORIES.

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE