def test_zenith_stationary(self):
rho = np.random.uniform(0, 1000)
az = 0
el = np.pi/2
drho = 0
daz = 0
dele = 0
rho_sez_expected = np.array([0, 0, rho])
rho_sez, drho_sez = geodetic.rhoazel2sez(rho, az, el, drho, daz, dele)
np.testing.assert_array_almost_equal(rho_sez, rho_sez_expected)
def test_horizon_east(self):
rho = np.random.uniform(0, 1000)
az = np.pi/2
el = 0
drho = 0
daz = 0
dele = 0
rho_sez_expected = np.array([0, rho, 0])
rho_sez, drho_sez = geodetic.rhoazel2sez(rho, az, el, drho, daz, dele)
np.testing.assert_array_almost_equal(rho_sez, rho_sez_expected)
def test_horizon_north_receeding(self):
rho = np.random.uniform(0, 1000)
az = 0
el = 0
drho = np.random.uniform(0, 10)
daz = 0
dele = 0
rho_sez_expected = np.array([-rho, 0, 0])
drho_sez_expected = np.array([-drho, 0, 0])
rho_sez, drho_sez = geodetic.rhoazel2sez(rho, az, el, drho, daz, dele)
np.testing.assert_array_almost_equal(rho_sez, rho_sez_expected)
np.testing.assert_array_almost_equal(drho_sez, drho_sez_expected)
def solution(meas_file='./data/COMFIX_tle_measurement.txt',
outfile='./data/COMFIX_tle_solution.txt'):
# read in the measurement data
fout = open(outfile, 'w')
with open(meas_file, 'r') as f:
l0 = f.readline().split()
l0 = [float(x) for x in l0]
while l0:
l1 = f.readline().split()
l1 = [float(x) for x in l1]
latgd, lon, alt, jd = np.deg2rad(l0[0]), np.deg2rad(
l0[1]), l0[2] / 1e3, l0[3]
satnum, rho, az, el, drho, daz, dele = l1[0], l1[1], np.deg2rad(
l1[2]), np.deg2rad(l1[3]), l1[4], np.deg2rad(
l1[5]), np.deg2rad(l1[6])
# GST, LST
gst, lst = time.gstlst(jd, lon)
# find satellite vector in SEZ
rho_sez, drho_sez = geodetic.rhoazel2sez(rho, az, el, drho, daz,
dele)
R_eci2ecef = geodetic.eci2ecef(jd)
R_ecef2eci = geodetic.ecef2eci(jd)
R_sez2ecef = transform.dcm_sez2ecef(latgd, lon, alt)
# find site vector in ECEF/ECI
site_ecef = geodetic.lla2ecef(latgd, lon, alt)
site_eci = R_ecef2eci.dot(site_ecef)
# transform satellite vector from SEZ to ECI
rho_ecef = R_sez2ecef.dot(rho_sez)
rho_eci = R_ecef2eci.dot(rho_ecef)
drho_ecef = R_sez2ecef.dot(drho_sez)
drho_eci = R_ecef2eci.dot(drho_ecef)
pos_eci = site_eci + rho_eci
vel_eci = drho_eci + np.cross(
np.array([0, 0, constants.earth.omega]), pos_eci)
# find orbital elements
p, a, ecc, inc, raan, arg_p, nu, _, _, _, _ = kepler.rv2coe(
pos_eci, vel_eci, constants.earth.mu)
# compute orbit properties
prop_string = kepler.orbit_el(p, ecc, inc, raan, arg_p, nu,
constants.earth.mu)
l0 = f.readline().split()
l0 = [float(x) for x in l0]
# output to text file
fout.write(
'#################### COMFIX SATELLITE {:g} ####################################\n\n'
.format(satnum))
fout.write(
'------------------------ INPUT DATA -------------------------------------------\n\n'
)
fout.write('LAT (deg) LON (deg) ALT (m) JD\n')
fout.write(
'{:<9.4f} {:<9.4f} {:<9.4f} {:<16.6f}\n\n'.format(
np.rad2deg(latgd), np.rad2deg(lon), alt * 1e3, jd))
fout.write(
'RHO (km) AZ (deg) EL (deg) DRHO (km/s) DAZ (deg/s) DEL (deg/s)\n'
)
fout.write(
'{:<9.4f} {:<6.4f} {:<6.4f} {:<6.4f} {:<6.4f} {:<6.4f}\n'
.format(rho, np.rad2deg(az), np.rad2deg(el), drho,
np.rad2deg(daz), np.rad2deg(dele)))
fout.write(
'------------------------- WORKING DATA ----------------------------------------\n\n'
)
fout.write('LAT (rad) LON (rad) ALT (m) JD\n')
fout.write(
'{:<9.4f} {:<9.4f} {:<9.4f} {:<16.6f}\n\n'.format(
latgd, lon, alt, jd))
fout.write(
'RHO (km) AZ (rad) EL (rad) DRHO (km/s) DAZ (rad/s) DEL (rad/s)\n'
)
fout.write(
'{:<9.4f} {:<6.4f} {:<6.4f} {:<6.4f} {:<6.4f} {:<6.4f}\n\n'
.format(rho, az, el, drho, daz, dele))
fout.write('GST = {:16.9f} rad = {:16.9f} deg\n'.format(
gst, np.rad2deg(gst)))
fout.write('LST = {:16.9f} rad = {:16.9f} deg\n\n'.format(
lst, np.rad2deg(lst)))
fout.write(
'---------------------------- VECTORS ------------------------------------------\n'
)
fout.write(
'{:9s} = {:13.4f} S {:13.4f} E {:13.4f} Z MAG = {:7.4f} km\n'.
format('rho_sez', rho_sez[0], rho_sez[1], rho_sez[2],
np.linalg.norm(rho_sez)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km\n'.
format('rho_ecef', rho_ecef[0], rho_ecef[1], rho_ecef[2],
np.linalg.norm(rho_ecef)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km\n'.
format('rho_eci', rho_eci[0], rho_eci[1], rho_eci[2],
np.linalg.norm(rho_eci)))
fout.write(
'{:9s} = {:13.4f} S {:13.4f} E {:13.4f} Z MAG = {:7.4f} km/s\n'
.format('drho_sez', drho_sez[0], drho_sez[1], drho_sez[2],
np.linalg.norm(drho_sez)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km/s\n'
.format('drho_ecef', drho_ecef[0], drho_ecef[1], drho_ecef[2],
np.linalg.norm(drho_ecef)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km/s\n'
.format('drho_eci', drho_eci[0], drho_eci[1], drho_eci[2],
np.linalg.norm(drho_eci)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km\n'.
format('site_ecef', site_ecef[0], site_ecef[1], site_ecef[2],
np.linalg.norm(site_ecef)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km\n'.
format('site_eci', site_eci[0], site_eci[1], site_eci[2],
np.linalg.norm(site_eci)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km\n'.
format('pos_eci', pos_eci[0], pos_eci[1], pos_eci[2],
np.linalg.norm(pos_eci)))
fout.write(
'{:9s} = {:13.4f} I {:13.4f} J {:13.4f} K MAG = {:7.4f} km/s\n'
.format('vel_eci', vel_eci[0], vel_eci[1], vel_eci[2],
np.linalg.norm(vel_eci)))
fout.write(prop_string + '\n')
fout.close()
gst, lst = time.gstlst(jd, lon)
print('JD : {}'.format(jd))
print('GST : {} rad = {} deg'.format(gst, np.rad2deg(gst)))
print('LST : {} rad = {} deg'.format(lst, np.rad2deg(lst)))
# site location
site_ecef = geodetic.lla2ecef(lat, lon, alt)
Recef2eci = transform.dcm_ecef2eci(jd)
site_eci = Recef2eci.dot(site_ecef)
print('Site ECEF : {} km'.format(site_ecef))
print('ECEF TO ECI : \n{}'.format(Recef2eci))
print('Site ECI : {} km'.format(site_eci))
# convert measurement to SEZ then to ECEF then to ECI
rho_sez, drho_sez = geodetic.rhoazel2sez(rho, az, el, rhodot, azdot, eldot)
R_sez2ecef = transform.dcm_sez2ecef(lat, lon, alt)
# transform satellite vector from SEZ to ECI
rho_ecef = R_sez2ecef.dot(rho_sez)
rho_eci = Recef2eci.dot(rho_ecef)
drho_ecef = R_sez2ecef.dot(drho_sez)
drho_eci = Recef2eci.dot(drho_ecef)
print('\nRHO SEZ : {} km'.format(rho_sez))
print('DRHO SEZ: {} km/sec'.format(drho_sez))
print('SEZ TO ECEF: \n{}'.format(R_sez2ecef))
print('RHO ECEF: {} km/sec'.format(rho_ecef))
print('DRHO ECEF: {} km/sec'.format(drho_ecef))