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# Module : constants
# Purpose : Define general constants
# Author : P. Rebischung
# Created : 04-Oct-2013
#
# Changes :
#
# Routines :
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# LIBRARIES
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from math import *
import numpy
# CONSTANTS
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# Agency
agency = 'IGN'
# Conversion factor from as, mas and uas to rad
as2rad = pi / 180 / 3600
mas2rad = as2rad / 1000
uas2rad = mas2rad / 1000
# Conversion factor from s, ms and us to rad
s2rad = pi / 12 / 3600
ms2rad = s2rad / 1000
us2rad = ms2rad / 1000
# MJD at epoch J2000
mjd2000 = 51544.5
# Offset between GPS time and TT
tt_gps = (19. + 32.184) / 86400.
# GPS-UTC leap seconds
gps_utc = numpy.arange(-9., 19.)
mjd_leap = numpy.array([41317., 41499., 41683., 42048., 42413., 42778., 43144.,
43509., 43874., 44239., 44786., 45151., 45516., 46247.,
47161., 47892., 48257., 48804., 49169., 49534., 50083.,
50630., 51179., 53736., 54832., 56109., 57204., 57754.])
# GRS80 parameters
ae = 6378137.
fe = 0.00335281068118
ee = sqrt(2*fe - fe**2)
be = ae * sqrt(1 - ee**2)
# Gravitational constant
G = 6.67428e-11
# Earth gravitational constant
GM = 3.986004418e14
# Mean equatorial gravity
ge = 9.7803278
# Mean Earth angular velocity
Oe = 7.292115e-5
# Astronomical unit (m)
AU = 149597870691.0
# Rate of advance of ERA
dera_dt = 1.00273781191135448
# DUMMY CLASS
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