API¶

Orbital computations¶

Module for computing the orbital parameters of satellites.

class pyorbital.orbital.OrbitElements(tle)¶: Class holding the orbital elements.

class pyorbital.orbital.Orbital(satellite, tle_file=None, line1=None, line2=None)¶

Class for orbital computations.

The satellite parameter is the name of the satellite to work on and is used to retreive the right TLE data for internet or from tle_file in case it is provided.

find_aol(utc_time, lon, lat)¶

find_aos(utc_time, lon, lat)¶

get_last_an_time(utc_time)¶: Calculate time of last ascending node relative to the specified time

get_lonlatalt(utc_time)¶: Calculate sublon, sublat and altitude of satellite. http://celestrak.com/columns/v02n03/

get_next_passes(utc_time, length, lon, lat, alt, tol=0.001, horizon=0)¶

Calculate passes for the next hours for a given start time and a given observer.

Original by Martin.

utc_time: Observation time (datetime object) length: Number of hours to find passes (int) lon: Longitude of observer position on ground (float) lat: Latitude of observer position on ground (float) alt: Altitude above sea-level (geoid) of observer position on ground (float) tol: precision of the result in seconds horizon: the elevation of horizon to compute risetime and falltime.

Return: [(rise-time, fall-time, max-elevation-time), …]

get_observer_look(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)

get_orbit_number(utc_time, tbus_style=False)¶: Calculate orbit number at specified time. Optionally use TBUS-style orbit numbering (TLE orbit number + 1)

get_position(utc_time, normalize=True)¶: Get the cartesian position and velocity from the satellite.

exception pyorbital.orbital.OrbitalError¶

pyorbital.orbital.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)

pyorbital.orbital.kep2xyz(kep)¶

TLE handling¶

exception pyorbital.tlefile.ChecksumError¶: ChecksumError.

pyorbital.tlefile.SATELLITES = {}¶

The platform numbers are given in a file $PPP_CONFIG/platforms.txt in the following format:

# Mappings between satellite catalogue numbers and corresponding # platform names from OSCAR. ALOS-2 39766 CloudSat 29107 CryoSat-2 36508 CSK-1 31598 CSK-2 32376 CSK-3 33412 CSK-4 37216 DMSP-F15 25991 DMSP-F16 28054 DMSP-F17 29522 DMSP-F18 35951 DMSP-F19 39630 EOS-Aqua 27424 EOS-Aura 28376 EOS-Terra 25994 FY-2D 29640 FY-2E 33463 FY-2F 38049 FY-2G 40367 FY-3A 32958 FY-3B 37214 FY-3C 39260 GOES-13 29155 GOES-14 35491 GOES-15 36411 Himawari-6 28622 Himawari-7 28937 Himawari-8 40267 INSAT-3A 27714 INSAT-3C 27298 INSAT-3D 39216 JASON-2 33105 Kalpana-1 27525 Landsat-7 25682 Landsat-8 39084 Meteosat-7 24932 Meteosat-8 27509 Meteosat-9 28912 Meteosat-10 38552 Metop-A 29499 Metop-B 38771 NOAA-15 25338 NOAA-16 26536 NOAA-17 27453 NOAA-18 28654 NOAA-19 33591 RadarSat-2 32382 Sentinel-1A 39634 SMOS 36036 SPOT-5 27421 SPOT-6 38755 SPOT-7 40053 Suomi-NPP 37849 TanDEM-X 36605 TerraSAR-X 31698

class pyorbital.tlefile.Tle(platform, tle_file=None, line1=None, line2=None)¶

Class holding TLE objects.

line1¶: Return first TLE line.

line2¶: Return second TLE line.

platform¶: Return satellite platform name.

pyorbital.tlefile.fetch(destination)¶: fetch TLE from internet and save it to destination.

pyorbital.tlefile.main()¶: Main for testing TLE reading.

pyorbital.tlefile.read(platform, tle_file=None, line1=None, line2=None)¶: Read TLE for satellite from tle_file, from line1 and line2, from the newest file provided in the TLES pattern, or from internet if none is provided.

pyorbital.tlefile.read_platform_numbers(in_upper=False, num_as_int=False)¶: Read platform numbers from $PPP_CONFIG_DIR/platforms.txt if available.

Astronomical computations¶

Astronomy module. Parts taken from http://www.geoastro.de/elevaz/basics/index.htm

pyorbital.astronomy.cos_zen(utc_time, lon, lat)¶: Cosine of the sun-zenith angle for lon, lat at utc_time. utc_time: datetime.datetime instance of the UTC time lon and lat in degrees.

pyorbital.astronomy.get_alt_az(utc_time, lon, lat)¶: Return sun altitude and azimuth from utc_time, lon, and lat. lon,lat in degrees What is the unit of the returned angles and heights!? FIXME!

pyorbital.astronomy.gmst(utc_time)¶

Greenwich mean sidereal utc_time, in radians.

As defined in the AIAA 2006 implementation: http://www.celestrak.com/publications/AIAA/2006-6753/

pyorbital.astronomy.jdays(utc_time)¶: Get the julian day of utc_time.

pyorbital.astronomy.jdays2000(utc_time)¶: Get the days since year 2000.

pyorbital.astronomy.observer_position(time, lon, lat, alt)¶

Calculate observer ECI position.

http://celestrak.com/columns/v02n03/

pyorbital.astronomy.sun_earth_distance_correction(utc_time)¶: Calculate the sun earth distance correction, relative to 1 AU.

pyorbital.astronomy.sun_ecliptic_longitude(utc_time)¶: Ecliptic longitude of the sun at utc_time.

pyorbital.astronomy.sun_ra_dec(utc_time)¶: Right ascension and declination of the sun at utc_time.

pyorbital.astronomy.sun_zenith_angle(utc_time, lon, lat)¶: Sun-zenith angle for lon, lat at utc_time. lon,lat in degrees. The angle returned is given in degrees