This submission is an interactive MATLAB script named npoe.m that can be used to propagate spacecraft in Earth orbits and model important orbital events. This script implements a special perturbation solution of orbital motion using a variable step size Runge-Kutta-Fehlberg (RKF78) integration method to numerically integrate Cowell’s form of the system of differential equations. Orbital events are predicted by embedding the RFK78 algorithm within Brent’s derivative-free methods for finding the single roots and extrema of nonlinear equations. The user can control both the integration and root-finding convergence criteria.
This MATLAB script can accurately predict the time and orbital characteristics for any physically realizable user-defined value of the following orbital elements
- argument of latitude
- geodetic altitude
- geodetic latitude
- right ascension
- geocentric declination
- east longitude
- flight path angle
- orbital speed
as well as extrema (minimum and maximum values) for these eight orbital elements.
The npoe software can also predict the circumstances of the following mission events
- spacecraft-to-moon visibility
- spacecraft-to-sun visibility
- Earth shadow - penumbra
- Earth shadow - umbra
- Moon shadow - penumbra
- Moon shadow - umbra
- observer-to-spacecraft visibility
This MATLAB script reads JPL lunar and solar ephemerides in a machine-independent binary format (kernels) which are available from the SPICE web site and by anonymous ftp from ftp://ssd.jpl.nasa.gov/pub/eph/planets/bsp. These *.bsp ephemeris files are IEEE-Little Endian style of binary kernel. This is the binary form native to PC/Linux, PC/Windows and MAC/Intel machines. Additional information about JPL ephemerides can be found at http://naif.jpl.nasa.gov/naif/.
The npoe script uses routines from the MICE software suite to read and evaluate the JPL binary ephemeris file. Platform-specific MICE mex files, support functions and the binary ephemeris file (de430_1850-2150.bsp) are available at naif.jpl.nasa.gov/naif/toolkit_MATLAB.html. MICE is a MATLAB implementation of the SPICE library created by JPL.
David Eagle (2023). Numerical Prediction of Orbital Events (https://www.mathworks.com/matlabcentral/fileexchange/106170-numerical-prediction-of-orbital-events), MATLAB Central File Exchange. 检索来源 .