OpenOrb - B612-Asteroid-Institute/orb_it Wiki

OpenOrb (oorb or pyoorb) is an open-source orbit-computation package.

OpenOrb is built on a well-established Bayesian inversion theory, which means that it is to a large part complementary to orbit-computation packages currently available. In particular, OpenOrb is the first package that contains tools for rigorously estimating the uncertainties resulting from the inverse problem of computing orbital elements using scarce astrometry. In addition to the well-known least-squares method, OpenOrb also contains both Monte-Carlo (MC) and Markov-Chain MC (MCMC; Oszkiewicz et al. [2009]) versions of the statistical ranging method.

-Excerpt from the abstract of Granvik et al. 2009


Open Orb's wiki provides helpful instructions on how to install OpenOrb. The install must include its python wrapper pyoorb for orb_it to work properly.

Running with orb_it

First you have to import it,

from orb_it.backend import PYOORB

PYOORB() class docstring,

Open Orb integrator backend for orb_it testing.

Keyword Arguments
    dynamical_model : str, optional
        The dynamical model the integrator uses. Defaults to "N".
    ephemeris_file : str, optional
        Name of the ephemeris file the integrator uses. Defaults to "de430.dat".
    config_path : str, optional
        Defines the path to the "data" folder where OORB configuration files are.
    multi_ranging : int, optional
        Indicates which multi_ranging method to use for an initial Orbit Determination fit. Defaults to 1.
        0 for no multi_ranging, all observations are given for initial fit. (Can be unstable for long arcs, more stable for short arcs)
        1 for basic multi_ranging, observations are split up into groups of 3-4, then fit separately. (Somewhat stable for longer arcs)
        2 for OrbFit style ranging, the first, middle, and last observations are only given to the fitter. (Somewhat stable for longer arcs)

    name : str
        Name of the integrator.

Ranging Issues

From Open Orb's wiki,

Ranging is optimized for cases where the amount of astrometry is scarce or spans a relatively short time span. Ranging-based methods have successfully been applied to a variety of different topics such as rigorous ephemeris prediction, orbital-element-distribution studies for trans-neptunian objects, the computation of invariant collision probabilities between NEOs and the Earth, detecting linkages between astrometric asteroid observations within an apparition as well as between apparitions, and in the rigorous analysis of the impact of orbital arc-length and/or astrometric uncertainty on the uncertainty of the resulting orbits.


Granvik, M., Virtanen, J., Oszkiewicz, D., Muinonen, K. (2009). 
OpenOrb: Open-source asteroid orbit computation software including statistical ranging. 
Meteoritics & Planetary Science 44(12), 1853-1861.