def test_geopack(self):
"""GSE to SM conversion verified by Slava Merkin using GEOPACK."""
x=0.25
y = -2.63
z = -0.4
# First day of NHL hockey season in '94-95. Stupid strike!
year = 1995
month = 1
day = 20
hour = 19
minute = 0
second = 0
out = cxform.transform('GSE', 'SM',
x,y,z,
year,month,day,hour,minute,second)
self.__assertPercentDiff( 0.025938911859381325, out[0] )
self.__assertPercentDiff( -2.3804487166857329, out[1] )
self.__assertPercentDiff( -1.2134184699432964, out[2] )
# Check the inverse:
out = cxform.transform('SM', 'GSE',
out[0], out[1], out[2],
year,month,day,hour,minute,second)
self.__assertPercentDiff( 0.25, out[0] )
self.__assertPercentDiff( -2.63, out[1] )
self.__assertPercentDiff( -0.4, out[2] )
def test_geopack(self):
"""GSE to SM conversion verified by Slava Merkin using GEOPACK."""
x=0.25
y = -2.63
z = -0.4
year = 2008
month = 8
day = 1
hour = 0
minute = 0
second = 0
out = cxform.transform('GSE', 'SM',
x,y,z,
year,month,day,hour,minute,second)
self.__assertPercentDiff( .2830, out[0] )
self.__assertPercentDiff( -2.6554, out[1] )
self.__assertPercentDiff( -.0899, out[2] )
# Check the inverse:
out = cxform.transform('SM', 'GSE',
out[0], out[1], out[2],
year,month,day,hour,minute,second)
self.__assertPercentDiff( 0.25, out[0] )
self.__assertPercentDiff( -2.63, out[1] )
self.__assertPercentDiff( -0.4, out[2] )
def test_2SM(self):
out = cxform.transform('J2000', 'SM',
self.x, self.y, self.z,
self.year, self.month, self.day, self.hour, self.minute, self.second)
self.__assertPercentDiff( -915527671.753106, out[0] )
self.__assertPercentDiff( -52303890.6954846, out[1] )
self.__assertPercentDiff( 115531839.327171, out[2] )
def test_2GSM(self):
out = cxform.transform('J2000', 'GSM',
self.x, self.y, self.z,
self.year, self.month, self.day, self.hour, self.minute, self.second)
self.__assertPercentDiff( -920802840.504282, out[0] )
self.__assertPercentDiff( -52303890.695484, out[1] )
self.__assertPercentDiff( -60503326.877360, out[2] )
def test_2GSE(self):
out = cxform.transform('J2000', 'GSE',
self.x, self.y, self.z,
self.year, self.month, self.day, self.hour, self.minute, self.second)
self.__assertPercentDiff( -920802840.504282, out[0] )
self.__assertPercentDiff( -64160872.043671027, out[1] )
self.__assertPercentDiff( -46046221.090855, out[2] )
def test_2GEO(self):
out = cxform.transform('J2000', 'GEO',
self.x, self.y, self.z,
self.year, self.month, self.day, self.hour, self.minute, self.second)
self.__assertPercentDiff( -664946479.875617, out[0] )
self.__assertPercentDiff( -640940392.874836, out[1] )
self.__assertPercentDiff( 44869503.669364, out[2] )
def test_merkin(self):
"""
Slava Merkin was experience strange behavior with cxform on
certain inputs. Let's try those inputs here & see if we can
break cxform!
"""
x=0.25
y = -2.63
z = -0.4
year = 2008
month = 8
day = 1
hour = 0
minute = 0
second = 0
# Transform twice in a row... make sure we get the same thing:
out = cxform.transform('GSE', 'GSM',
x,y,z,
year,month,day, hour,minute,second)
self.__assertPercentDiff( 0.25, out[0] )
self.__assertPercentDiff( -2.6556295971324912, out[1] )
self.__assertPercentDiff( -0.15662516666844989, out[2] )
out = cxform.transform('GSE', 'GSM',
x,y,z,
year,month,day, hour,minute,second)
self.__assertPercentDiff( 0.25, out[0] )
self.__assertPercentDiff( -2.6556295971324912, out[1] )
self.__assertPercentDiff( -0.15662516666844989, out[2] )
# Now do the inverse transform & make sure we get the same thing.
out = cxform.transform('GSM', 'GSE',
out[0], out[1], out[2],
year,month,day, hour,minute,second)
self.__assertPercentDiff( 0.25, out[0] )
self.__assertPercentDiff( -2.6299999999999994, out[1] )
self.__assertPercentDiff( -0.39999999999999997, out[2] )
def coord(idSatellite, dtList):
"""Calculate spacecraft coordinates in several systems (predefined).
For performance considerations, the TLE file is only retrieved once per
coord() call, so if you need to process a very long time interval,
split it into several shorter ones in order to reduce inaccuracies
in the TLE file and make the orbital drift negligible.
"""
res = []
if len(dtList) == 0:
return res
tle = gettle(idSatellite, dtList[0]).split("\n")[:-1] # Strip the newline
sat = ephem.readtle(tle[0], tle[1], tle[2])
for dt in dtList:
sat.compute(dt)
lat, lon, alt = sat.sublat, sat.sublong, float(sat.elevation) / 1000
lat, lon = dddmmss2dec(str(lat), str(lon))
if lon < 0:
lon += 360
year = dt.year + float(dt.strftime("%j")) / daysinyear(dt.year)
# Cartesian geographic coordinates, magnetic field components,
# total magnetic field magnitude and the L-shell
icode, l, b = igrf.lb(lat, lon, alt, year)
bnorth, beast, bdown, b = igrf.b(lat, lon, alt, year)
bx, by, bz = enu2ecef(lat, lon, alt, bnorth, beast, bdown)
x, y, z = geodetic2ecef(lat, lon, alt)
# Local time
lt = dt + timedelta(hours = (float(lon) / 15))
lt = lt.hour + lt.minute / 60.0 + lt.second / 3600.0 + \
lt.microsecond / (3600000000.0)
# Geomagnetic
x, y, z = cxform.transform("GEO", "MAG", x, y, z,
dt.year, dt.month, dt.day, dt.hour, dt.minute,
int(round(dt.second + (dt.microsecond + 0.0) / 1000)))
mlat, mlon = ecef2geodetic(x, y, z)
res.append((lat, lon, alt, x, y, z, mlat, mlon, l, b, bx, by, bz, lt))
return res
import cxform
def printCoordinates(system, xyz):
print 'Input Vector (%s):\t %f\t %f\t %f' % (system, xyz[0], xyz[1], xyz[2])
base = 'J2000'
systems = ['GEO', 'GSE', 'GSM', 'SM']
year=2005
month=3
day=2
hour=9
minute=28
second=11
xyzIn = [-896921337.28302002, 220296912.43620300, 44419205.01961136]
printCoordinates(base, xyzIn)
for trans in systems:
xyzOut = cxform.transform(base, trans, xyzIn[0], xyzIn[1], xyzIn[2], year,month,day, hour,minute,second)
printCoordinates(trans, xyzOut)
print "Output exepected:"
print """Input Vector (J2000):\t -896921337.283020\t 220296912.436203\t 44419205.019611
Output Vector (GEO):\t -664946479.875617\t -640940392.874836\t 44869503.669364
Output Vector (GSE):\t -920802840.504282\t -70523436.668648\t -46046221.090855
Output Vector (GSM):\t -920802840.504282\t -58593148.345827\t -60503326.877360
Output Vector (SM):\t -915527671.753106\t -58593148.345827\t 115531839.327171
"""