def test_subpoint_with_wrong_center(ts, angle):
t = ts.utc(2020, 12, 31)
p = Barycentric([0,0,0], t=t)
with assert_raises(ValueError, 'a geographic subpoint can only be'
' calculated for positions measured from 399, the center'
' of the Earth, but this position has center 0'):
wgs84.subpoint(p)
def test_subpoint_with_wrong_center(ts, angle):
t = ts.utc(2020, 12, 31)
p = Barycentric([0, 0, 0], t=t)
with assert_raises(
ValueError, 'you can only calculate a geographic'
' position from a position which is geocentric'
' .center=399., but this position has a center of 0'):
wgs84.subpoint(p)
def test_latlon_and_subpoint_methods(ts, angle):
t = ts.utc(2020, 11, 3, 17, 5)
g = wgs84.latlon(angle, 2 * angle, elevation_m=1234.0)
pos = g.at(t)
def check_lat(lat):
assert abs(g.latitude.mas() - lat.mas()) < 0.1
def check_lon(lon):
assert abs(g.longitude.mas() - lon.mas()) < 0.1
def check_height(h):
assert abs(g.elevation.m - h.m) < 1e-7
lat, lon = wgs84.latlon_of(pos)
check_lat(lat)
check_lon(lon)
height = wgs84.height_of(pos)
check_height(height)
g = wgs84.geographic_position_of(pos)
check_lat(g.latitude)
check_lon(g.longitude)
check_height(g.elevation)
g = wgs84.subpoint(pos) # old deprecated method name
check_lat(g.latitude)
check_lon(g.longitude)
check_height(g.elevation)
g = wgs84.subpoint_of(pos)
check_lat(g.latitude)
check_lon(g.longitude)
assert g.elevation.m == 0.0
def getLonLatAlt(self):
"""Get longitude, latitude, and altitude """
pv_list = self.getPV()
subpoint = wgs84.subpoint(pv_list[0])
print("Longitude: {}".format(subpoint.longitude))
print("Latitude: {}".format(subpoint.latitude))
print("Altitude (in kilometers): {}".format(subpoint.elevation.km))
def test_wgs84_round_trip_with_polar_motion(ts, angle):
t = ts.utc(2018, 1, 19, 14, 37, 55)
ts.polar_motion_table = [0.0], [0.003483], [0.358609]
top = wgs84.latlon(angle, angle, elevation_m=0.0)
p = top.at(t)
b = wgs84.subpoint(p)
error_degrees = abs(b.latitude.degrees - angle)
error_mas = 60.0 * 60.0 * 1000.0 * error_degrees
assert error_mas < 0.1
error_degrees = abs(b.longitude.degrees - angle)
error_mas = 60.0 * 60.0 * 1000.0 * error_degrees
assert error_mas < 0.1
def test_wgs84_subpoint(ts, angle):
t = ts.utc(2018, 1, 19, 14, 37, 55)
# An elevation of 0 is more difficult for the routine's accuracy
# than a very large elevation.
top = wgs84.latlon(angle, angle, elevation_m=0.0)
p = top.at(t)
b = wgs84.subpoint(p)
error_degrees = abs(b.latitude.degrees - angle)
error_mas = 60.0 * 60.0 * 1000.0 * error_degrees
assert error_mas < 0.1
error_degrees = abs(b.longitude.degrees - angle)
error_mas = 60.0 * 60.0 * 1000.0 * error_degrees
assert error_mas < 0.1
def subpoint(self, target: CelestialObject,
time: Time) -> GeographicPosition:
return wgs84.subpoint(
self.earth.position.at(time).observe(target.position))
print("ISS (ZARYA) catalog #25544 \nepoch 2021-01-15 06:17:01 UTC")
#print(satellite.epoch.utc_jpl())
ts = load.timescale()
t = ts.now()
# datetime object containing current date and time
now = datetime.now()
dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
print()
print("date and time =", dt_string)
geocentric = satellite.at(t)
#print(geocentric.position.km)
subpoint = wgs84.subpoint(geocentric)
print(subpoint)
print('Latitude:', subpoint.latitude)
print('Longitude:', subpoint.longitude)
print('Elevation (m):', int(subpoint.elevation.m))
print()
#(z, e, n) = LLtoUTM(23,subpoint.latitude, subpoint.longitude)
me = wgs84.latlon(48.873459, 2.358040)
difference = satellite - me
#print(difference)
topocentric = difference.at(t)
from skyfield.api import EarthSatellite, N, W, wgs84, load ts = load.timescale() t = ts.now() line1 = '1 25544U 98067A 14020.93268519 .00009878 00000-0 18200-3 0 5082' line2 = '2 25544 51.6498 109.4756 0003572 55.9686 274.8005 15.49815350868473' boston = wgs84.latlon(42.3583 * N, 71.0603 * W, elevation_m=43) satellite = EarthSatellite(line1, line2, name='ISS (ZARYA)') # Geocentric geometry = satellite.at(t) # Geographic point beneath satellite subpoint = wgs84.subpoint(geometry) latitude = subpoint.latitude longitude = subpoint.longitude elevation = subpoint.elevation # Topocentric difference = satellite - boston geometry = difference.at(t)
def main():
# Starlink data can be corrupted, let double_scalar warnings go unnoticed
warnings.filterwarnings("ignore")
ts = load.timescale()
t = ts.now()
max_range = int(input("Enter the air distance in km: "))
g = nx.Graph()
kml = simplekml.Kml()
kml_entries = []
get_user_input()
starlink_url = 'http://www.celestrak.com/NORAD/elements/starlink.txt'
satellites = load.tle_file(starlink_url)
# distance between ground and satellite
for satellite in satellites:
# print(satellite) # prints more info on the satellite
if satellite.name != "FALCON 9 DEB": # We don't want to get info about FALCON 9
# Geocentric
geometry = satellite.at(t)
# Geographic point beneath satellite
subpoint = wgs84.subpoint(geometry)
latitude = subpoint.latitude
longitude = subpoint.longitude
satellite_info = {
"name": satellite.name,
"latitude": latitude.degrees,
"longitude": longitude.degrees
}
kml_entries.append(satellite_info)
dist1 = calculate_distance(start_point, satellite_info)
dist2 = calculate_distance(end_point, satellite_info)
if dist1 < max_range:
g.add_edge(start_point["name"],
satellite_info["name"],
weight=dist1)
if dist2 < max_range:
g.add_edge(end_point["name"],
satellite_info["name"],
weight=dist2)
# distance between two earth satellite
for i in range(0, len(satellites)):
for j in range(i + 1, len(satellites) - 1):
if satellites[i].name != "FALCON 9 DEB" and satellites[
j].name != "FALCON 9 DEB":
distance = (satellites[i].at(t) -
satellites[j].at(t)).distance().km
if distance < max_range:
g.add_edge(satellites[i].name,
satellites[j].name,
weight=distance)
pos = nx.spring_layout(g)
# This option can add satellites name into the graph
# nx.draw(g, pos, node_color='b', with_labels = True, font_size=10)
nx.draw(g, pos, node_color='b')
# draw path in red
path = nx.shortest_path(g, source="Start Point", target="End Point")
print(path)
# Generate KML for Google Earth
kml_coords = []
kml_coords.append((start_point["longitude"], start_point["latitude"]))
for point in path[1:-1]:
kml_entry = get_kml_entry(satellite_name=point,
kml_entries=kml_entries)
kml_coords.append((kml_entry["longitude"], kml_entry["latitude"]))
kml_coords.append((end_point["longitude"], end_point["latitude"]))
kml.newlinestring(name="Path",
description="Shortest path via satellites",
coords=kml_coords)
kml.save('google_earth_data.kml')
path_edges = list(zip(path, path[1:]))
nx.draw_networkx_nodes(g,
pos,
nodelist=path,
node_color='r',
node_size=400)
nx.draw_networkx_edges(g,
pos,
edgelist=set(path_edges),
edge_color='r',
width=10)
plt.axis('equal')
plt.show()