ivLam2

The code solves the single- and multiple-revolution Lambert's Problem (boundary value problem for motion governed by Keplerian dynamics) and returns all solutions including optional first and second order sensitivities of the outputs (velocities) with respect to inputs (positions and time of flight). The version 2.XX of code accompanies the paper [2] and includes sensitivity calculations, a much smaller data file and essentially no limits on flight time or number of revolutions. The updated approach is based on the vercosine formulation [1] and uses an efficient interpolation scheme to seed accurate initial guesses for a third-order root-solver that globally converges over the full domain. The code is demonstrated in [2] to me more that twice as fast as Gooding's state of the art method. The interpolation requires a single ~1 MB coefficient file, also available for download. The code is described in the papers below: [1] Russell, Ryan P., “On the Solution to Every Lambert Problem,” Celestial Mechanics and Dynamical Astronomy, Vol. 131, No. 50, pp. 1-33, 2019, https://doi.org/10.1007/s10569-019-9927-z [2] Russell, Ryan P., "Complete Lambert Solver Including Second-Order Sensitivities", Journal of Guidance, Control, and Dynamics, accepted 2021, to appear, https://doi.org/10.2514/1.G006089 For more details and potential updates, see http://russell.ae.utexas.edu/index_files/lambert.htm