def get_observer_look(sat_lon, sat_lat, sat_alt, utc_time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
utc_time: Observation time (datetime object)
lon: Longitude of observer position on ground in degrees east
lat: Latitude of observer position on ground in degrees north
alt: Altitude above sea-level (geoid) of observer position on ground in km
Return: (Azimuth, Elevation)
"""
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = astronomy.observer_position(
utc_time, sat_lon, sat_lat, sat_alt)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(utc_time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(utc_time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + \
sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + \
cos_lat * sin_theta * ry + sin_lat * rz
az_ = np.arctan(-top_e / top_s)
if has_xarray and isinstance(az_, xr.DataArray):
az_data = az_.data
else:
az_data = az_
if has_dask and isinstance(az_data, da.Array):
az_data = da.where(top_s > 0, az_data + np.pi, az_data)
az_data = da.where(az_data < 0, az_data + 2 * np.pi, az_data)
else:
az_data[np.where(top_s > 0)] += np.pi
az_data[np.where(az_data < 0)] += 2 * np.pi
if has_xarray and isinstance(az_, xr.DataArray):
az_.data = az_data
else:
az_ = az_data
rg_ = np.sqrt(rx * rx + ry * ry + rz * rz)
el_ = np.arcsin(top_z / rg_)
return np.rad2deg(az_), np.rad2deg(el_)
def get_observer_look(sat_lon, sat_lat, sat_alt, utc_time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
:utc_time: Observation time (datetime object)
:lon: Longitude of observer position on ground in degrees east
:lat: Latitude of observer position on ground in degrees north
:alt: Altitude above sea-level (geoid) of observer position on ground in km
:return: (Azimuth, Elevation)
"""
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = astronomy.observer_position(
utc_time, sat_lon, sat_lat, sat_alt)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(utc_time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(utc_time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + \
sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + \
cos_lat * sin_theta * ry + sin_lat * rz
az_ = np.arctan(-top_e / top_s)
if has_xarray and isinstance(az_, xr.DataArray):
az_data = az_.data
else:
az_data = az_
if has_dask and isinstance(az_data, da.Array):
az_data = da.where(top_s > 0, az_data + np.pi, az_data)
az_data = da.where(az_data < 0, az_data + 2 * np.pi, az_data)
else:
az_data[np.where(top_s > 0)] += np.pi
az_data[np.where(az_data < 0)] += 2 * np.pi
if has_xarray and isinstance(az_, xr.DataArray):
az_.data = az_data
else:
az_ = az_data
rg_ = np.sqrt(rx * rx + ry * ry + rz * rz)
el_ = np.arcsin(top_z / rg_)
return np.rad2deg(az_), np.rad2deg(el_)
def get_observer_look(sat_lon, sat_lat, sat_alt, utc_time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
utc_time: Observation time (datetime object)
lon: Longitude of observer position on ground in degrees east
lat: Latitude of observer position on ground in degrees north
alt: Altitude above sea-level (geoid) of observer position on ground in km
Return: (Azimuth, Elevation)
"""
utc_time = dt2np(utc_time)
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = astronomy.observer_position(
utc_time, sat_lon, sat_lat, sat_alt)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(utc_time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(utc_time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + \
sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + \
cos_lat * sin_theta * ry + sin_lat * rz
az_ = np.arctan(-top_e / top_s)
az_ = np.where(top_s > 0, az_ + np.pi, az_)
az_ = np.where(az_ < 0, az_ + 2 * np.pi, az_)
rg_ = np.sqrt(rx * rx + ry * ry + rz * rz)
el_ = np.arcsin(top_z / rg_)
return np.rad2deg(az_), np.rad2deg(el_)
def getDistance(self, satID, time, lat, lon, alt):
(lon2, lat2, alt2) = self.orbByID[satID].get_lonlatalt(time)
(pos_x, pos_y,
pos_z), (vel_x, vel_y,
vel_z) = astronomy.observer_position(time, lon2, lat2, alt2)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(time, lon, lat, alt)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
vx = vel_x - ovel_x
vy = vel_y - ovel_y
vz = vel_z - ovel_z
r = math.sqrt(rx * rx + ry * ry + rz * rz)
v = math.sqrt(vx * vx + vy * vy + vz * vz)
return (alt2, r, v)
def get_observer_look(self, time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
time: Observation time (datetime object)
lon: Longitude of observer position on ground
lat: Latitude of observer position on ground
alt: Altitude above sea-level (geoid) of observer position on ground
Return: (Azimuth, Elevation)
"""
(pos_x, pos_y, pos_z), (vel_x, vel_y,
vel_z) = self.get_position(time,
normalize=False)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
rvx = vel_x - ovel_x
rvy = vel_y - ovel_y
rvz = vel_z - ovel_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + cos_lat * sin_theta * ry + sin_lat * rz
az = np.arctan(-top_e / top_s)
if top_s > 0:
az = az + np.pi
if az < 0:
az = az + 2 * np.pi
rg = np.sqrt(rx * rx + ry * ry + rz * rz)
el = np.arcsin(top_z / rg)
w = (rx * rvx + ry * rvy + rz * rvz) / rg
return np.rad2deg(az), np.rad2deg(el)
def get_observer_look(self, utc_time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
utc_time: Observation time (datetime object)
lon: Longitude of observer position on ground in degrees east
lat: Latitude of observer position on ground in degrees north
alt: Altitude above sea-level (geoid) of observer position on ground in km
Return: (Azimuth, Elevation)
"""
utc_time = dt2np(utc_time)
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = self.get_position(
utc_time, normalize=False)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(utc_time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(utc_time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + \
sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + \
cos_lat * sin_theta * ry + sin_lat * rz
az_ = np.arctan(-top_e / top_s)
az_ = np.where(top_s > 0, az_ + np.pi, az_)
az_ = np.where(az_ < 0, az_ + 2 * np.pi, az_)
rg_ = np.sqrt(rx * rx + ry * ry + rz * rz)
el_ = np.arcsin(top_z / rg_)
return np.rad2deg(az_), np.rad2deg(el_)
def get_observer_look(self, time, lon, lat, alt):
"""Calculate observers look angle to a satellite.
http://celestrak.com/columns/v02n02/
time: Observation time (datetime object)
lon: Longitude of observer position on ground
lat: Latitude of observer position on ground
alt: Altitude above sea-level (geoid) of observer position on ground
Return: (Azimuth, Elevation)
"""
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = self.get_position(time, normalize=False)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(time, lon, lat, alt)
lon = np.deg2rad(lon)
lat = np.deg2rad(lat)
theta = (astronomy.gmst(time) + lon) % (2 * np.pi)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
rvx = vel_x - ovel_x
rvy = vel_y - ovel_y
rvz = vel_z - ovel_z
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * rx + sin_lat * sin_theta * ry - cos_lat * rz
top_e = -sin_theta * rx + cos_theta * ry
top_z = cos_lat * cos_theta * rx + cos_lat * sin_theta * ry + sin_lat * rz
az = np.arctan(-top_e / top_s)
if top_s > 0:
az = az + np.pi
if az < 0:
az = az + 2 * np.pi
rg = np.sqrt(rx * rx + ry * ry + rz * rz)
el = np.arcsin(top_z / rg)
w = (rx * rvx + ry * rvy + rz * rvz) / rg
return np.rad2deg(az), np.rad2deg(el)
def getDistance(self, satID, time, lat, lon, alt):
# Get satellite position (lat/lon/altitude)
(lon2, lat2, alt2) = self.orbByID[satID].get_lonlatalt(time)
(pos_x, pos_y, pos_z), (vel_x, vel_y, vel_z) = \
self.orbByID[satID].get_position(time, normalize=False)
(opos_x, opos_y, opos_z), (ovel_x, ovel_y, ovel_z) = \
astronomy.observer_position(time, lon, lat, alt)
rx = pos_x - opos_x
ry = pos_y - opos_y
rz = pos_z - opos_z
vx = vel_x - ovel_x
vy = vel_y - ovel_y
vz = vel_z - ovel_z
r = math.sqrt(rx * rx + ry * ry + rz * rz)
v = math.sqrt(vx * vx + vy * vy + vz * vz)
v_r = (rx * vx + ry * vy + rz * vz) / (r) # Radial projection
return (alt2, r, v, v_r)
def findtask(norad_id, observation_time, LAT, LONG, ALT):
id = norad_id
id = id.rjust(5)
counter = 0
with open('3le.txt', 'r') as TLEs:
for line in TLEs:
if line[2:7] == id and counter == 0:
# print(line)
line1 = line
counter = 1
elif line[2:7] == id and counter == 1:
line2 = line
# print(line)
break
R_site_ECI, V_site_ECI = observer_position(observation_time, LONG, LAT, ALT)
sat = satellite.get_sat(line1, line2)
R_sat_ECI, V_sat_ECI = sat.propagate(observation_time.year, observation_time.month, observation_time.day, observation_time.hour, observation_time.minute,
(observation_time.second + observation_time.microsecond * 10 ** (-6)))
delta_R = np.array([[R_sat_ECI[0] - R_site_ECI[0]], [R_sat_ECI[1] - R_site_ECI[1]], [R_sat_ECI[2] - R_site_ECI[2]]])
delta_V = np.array([[V_sat_ECI[0] - V_site_ECI[0]], [V_sat_ECI[1] - V_site_ECI[1]], [V_sat_ECI[2] - V_site_ECI[2]]])
utc_time = dt2np(observation_time)
lon = np.deg2rad(LONG)
lat = np.deg2rad(LAT)
theta = (astronomy.gmst(utc_time) + lon) % (2 * np.pi)
sin_lat = np.sin(lat)
cos_lat = np.cos(lat)
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
top_s = sin_lat * cos_theta * delta_R[0] + \
sin_lat * sin_theta * delta_R[1] - cos_lat * delta_R[2]
top_e = -sin_theta * delta_R[0] + cos_theta * delta_R[1]
top_z = cos_lat * cos_theta * delta_R[0] + \
cos_lat * sin_theta * delta_R[1] + sin_lat * delta_R[2]
az_ = np.arctan(-top_e / top_s)
az_ = np.where(top_s > 0, az_ + np.pi, az_)
az_ = np.where(az_ < 0, az_ + 2 * np.pi, az_)
rg_ = np.sqrt(top_s * top_s + top_e * top_e + top_z * top_z)
el_ = np.arcsin(top_z / rg_)
AZ = np.rad2deg(az_)
EL = np.rad2deg(el_)
mag_delta_R = math.sqrt(delta_R[0] ** 2 + delta_R[1] ** 2 + delta_R[2] ** 2)
unit_delta_R = np.array([delta_R[0] / mag_delta_R, delta_R[1] / mag_delta_R, delta_R[2] / mag_delta_R])
V_orth_R_ECI = logical_cross(logical_cross(unit_delta_R, delta_V), unit_delta_R)
total_look_angular_rate = (math.sqrt(V_orth_R_ECI[0] ** 2 + V_orth_R_ECI[1] ** 2 + V_orth_R_ECI[2] ** 2) / \
math.sqrt(delta_R[0] ** 2 + delta_R[1] ** 2 + delta_R[2] ** 2)) * (180.0 / math.pi)
exposure_time = 0.955/total_look_angular_rate
if exposure_time > 10:
exposure_time = 10
return [AZ[0], EL[0], total_look_angular_rate, exposure_time]
