DistanceProjectionInitializer

class ssapy.rvsampler.DistanceProjectionInitializer(arc, rho, indices=[0, 1], rSigma=np.float64(4216417.236450565), vSigma=np.float64(307.46599995993046))

Bases: object

Initialize position and velocity from two closely spaced (in time) observations of ra/dec. The position is initialized by projecting along the direction of the first observation a given slant range. The velocity is then initialized assuming that the slant range derivative is zero, and that the motion in between observations is inertial.

Parameters:

• arc (QTable with columns for 'ra', 'dec', 'rStation_GCRF'.) – The set of observations used to initialize samples. Note, only the first row of the given QTable will be used.

• rho (Distance in meters to project, measured from the position of the) – observer (not the center of the Earth).

• indices (list of indices indicating which two observations in arc to use) – for initialization. Default: [0, 1]; i.e., use the first two observations.

• rSigma (float, optional) – Standard deviation of sample positions dispersion in meters.

• vSigma (float, optional) – Standard deviation of sample velocity dispersion in meters per second.

observations

Indicated two rows of the input arc.

Type:

QTable

rho

rSigma

vSigma

__call__(nSample)

Returns nSample initial samples.

Methods Summary

__call__(nSample)

Call self as a function.

Methods Documentation

__call__(nSample)

Call self as a function.