orbdetpy is a Python orbit determination library.

Features

Dynamics in orbdetpy can be configured with:

1. EGM96 gravity field up to degree and order 360.
2. Earth solid tides due to the influence of the Sun and Moon.
3. FES 2004 ocean tide model up to degree and order 100.
4. NRL MSISE-00 and exponential atmospheric drag models.
5. Solar radiation pressure.
6. Third body perturbations from the Sun and Moon.
7. Satellite box-wing models and maneuvers.

Range, range-rate, angles, and inertial state measurements are supported. Filtering can be done with an EKF, UKF, or Batch Least Squares. Dynamic Model Compensation (DMC) can be used to estimate unmodeled accelerations.

Installation

If you have docker installed and wish to use a pre-built environment refer to the Docker section in this README.

1. Install Java SE 11 (11.0.10) from https://www.oracle.com/javadownload. Set the JAVA_HOME environment variable to the Java installation folder. The java executable must be added to the system path.

2. Install Python 3.8.0 or higher and run pip install orbdetpy to install orbdetpy and other package dependencies.

3. Update the astrodynamics data under orbdetpy/orekit-data periodically by running the following. You will need root privileges on some systems.

python -c "from orbdetpy.astro_data import update_data; update_data();"

Development

1. Download and extract https://github.com/ut-astria/orbdetpy/releases/download/2.1.0/orekit-data.tar.gz under the orbdetpy/ sub-folder.

2. Developers will need Apache Maven 3+ to build the Java library. Build using the following from the orbdetpy/ sub-folder, where os_cpu_type is linux-x86_64, linux-x86_32, windows-x86_64, windows-x86_32, osx-x86_64, or osx-x86_32 depending on your CPU and OS:

mvn -e -Dos.detected.classifier=os_cpu_type package

The command-line is simpler on Intel/AMD 64-bit Linux:

mvn -e package

1. Run pip install -e ./ from the top-level folder containing setup.py.

Docker

1. Build the docker image on a machine that has docker installed and go to the root folder of this repository where the Dockerfile is and run, docker build --build-arg ORBDETPY_VERSION=2.0.7 -t orbdetpy:2.0.7 .

2. Run orbdetpy:2.0.7 image in a daemon state: docker run -it --rm orbdetpy:2.0.7 bash

3. Next we will activate the python environment and run a test to determine a successful docker image build

cd && . env_orbdetpy/bin/activate && python orbdetpy/examples/test_estimation.py

1. From here, you can either develop in orbdetpy or build scripts and test in this pre-built environment

Examples

1. fit_radec.py : Run OD with real angles measurements. Also demonstrates the Laplace IOD method for estimating an initial state vector.

2. interpolate_oem.py : Command-line tool for interpolating state vectors from CCSDS OEM ephemeris files. OEM files are available for download at http://astria.tacc.utexas.edu/AstriaGraph.

3. predict_passes.py : Predict satellite passes for ground stations or geographic regions using TLEs. Current elements may be obtained from sites such as http://www.celestrak.com.

4. propagate_tle.py : Propagate TLEs given by command-line arguments.

5. test_conversion.py : Test reference frame and other conversion functions.

6. test_estimation.py : Demonstrates measurement simulation and orbit determination functions.

7. test_interpolation.py : Interpolate state vectors.

Known Issues

1. Give orbdetpy network access permissions if you get warnings from the Microsoft Windows Firewall.

2. If you use orbdetpy with Python's multiprocessing package, call the function multiprocessing.set_start_method("spawn") before other multiprocessing calls.

Sub-modules

orbdetpy.astro_data

orbdetpy.ccsds

orbdetpy.conversion

orbdetpy.estimation

orbdetpy.plotting

orbdetpy.propagation

orbdetpy.rpc

orbdetpy.utilities

orbdetpy.version

Functions

def add_facet(cfg: messages_pb2.Settings, normal: Tuple[float, float, float], area: float) ‑> messages_pb2.Facet

Add a facet to a box-wing spacecraft model.

Parameters

cfg : Settings object. normal : Facet unit outward normal vector in the spacecraft's co-moving LVLH frame. area : Facet area [m^2].

Returns

Added Facet object

 

def add_maneuver(cfg: messages_pb2.Settings, time: float, trigger_event: int, trigger_params: Optional[List[float]], maneuver_type: int, maneuver_params: Optional[List[float]]) ‑> messages_pb2.Maneuver

Add maneuver to propagation force models.

Parameters

cfg : Settings object. time : TT offset from J2000 epoch [s]. trigger_event : Constant from ManeuverTrigger. trigger_params : Additional data for trigger event. maneuver_type : Constant from ManeuverType. maneuver_params : Additional maneuver specific data.

Returns

Added Maneuver object.

def add_station(cfg: messages_pb2.Settings, name: str, latitude: float, longitude: float, altitude: float, fov_azimuth: float = None, fov_elevation: float = None, fov_aperture: float = None, bias: Optional[List[float]] = None, bias_estimation: int = None) ‑> messages_pb2.Station

Add a ground station.

Parameters

cfg : Settings object. name : Station name. latitude : Station WGS-84 latitude [rad]. longitude : Station WGS-84 longitude [rad]. altitude : Station height above WGS-84 reference geoid [m]. fov_azimuth : FOV center azimuth [rad]. fov_elevation : FOV center elevation [rad]. fov_aperture : FOV aperture angle [rad]. bias : Measurement biases. bias_estimation : Constant from EstimationType.

Returns

Added Station object.

def build_measurement(time: float, station_name: str, values: List[float], angle_rates: Optional[List[float]] = None) ‑> messages_pb2.Measurement

Build Measurement object from observed or simulated data.

Parameters

time : Measurement time; TT offset from J2000 epoch [s]. station_name : Station name. values : Measurement data corresponding to types configured in Settings object. angle_rates : Optional time rates of angle measurements [rad/s].

Returns

Measurement object.

def configure(**kwargs) ‑> messages_pb2.Settings

Create Settings object with default values.

Parameters

**kwargs : Keyword arguments for non-default parameters.

Returns

Settings object initialized with defaults and given values.

Classes

class AttitudeType

Orekit attitude providers.

Class variables

var BODY_CENTER_POINTING

var FIXED_RATE

var NADIR_POINTING

var UNDEFINED

class Constant

Miscellaneous constants.

Class variables

var ARC_SECOND_TO_RAD

var DEGREE_TO_RAD

var MINUS_I

var MINUS_J

var MINUS_K

var PLUS_I

var PLUS_J

var PLUS_K

var ZERO_VECTOR

class DragModel

Atmospheric drag density models.

Class variables

var EXPONENTIAL

var MSISE2000

var UNDEFINED

var WAM

class Epoch

Orekit AbsoluteDate epochs.

Class variables

var BEIDOU_EPOCH

var CCSDS_EPOCH

var FIFTIES_EPOCH

var GALILEO_EPOCH

var GLONASS_EPOCH

var GPS_EPOCH

var IRNSS_EPOCH

var J2000_EPOCH

var JULIAN_EPOCH

var MODIFIED_JULIAN_EPOCH

var QZSS_EPOCH

var UNIX_EPOCH

class EstimationType

Parameter estimation types.

Class variables

var CONSIDER

var ESTIMATE

var UNDEFINED

class Facet (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

Instance variables

var area

Field Facet.area

var normal

Field Facet.normal

class Filter

Estimation filters.

Class variables

var BATCH_LEAST_SQUARES

var EXTENDED_KALMAN

var UNSCENTED_KALMAN

class Frame

Orekit reference frames.

Class variables

var CIRF_CONVENTIONS_1996_ACCURATE_EOP

var CIRF_CONVENTIONS_1996_SIMPLE_EOP

var CIRF_CONVENTIONS_2003_ACCURATE_EOP

var CIRF_CONVENTIONS_2003_SIMPLE_EOP

var CIRF_CONVENTIONS_2010_ACCURATE_EOP

var CIRF_CONVENTIONS_2010_SIMPLE_EOP

var ECLIPTIC_CONVENTIONS_1996

var ECLIPTIC_CONVENTIONS_2003

var ECLIPTIC_CONVENTIONS_2010

var EME2000

var GCRF

var GTOD_CONVENTIONS_1996_ACCURATE_EOP

var GTOD_CONVENTIONS_1996_SIMPLE_EOP

var GTOD_CONVENTIONS_2003_ACCURATE_EOP

var GTOD_CONVENTIONS_2003_SIMPLE_EOP

var GTOD_CONVENTIONS_2010_ACCURATE_EOP

var GTOD_CONVENTIONS_2010_SIMPLE_EOP

var GTOD_WITHOUT_EOP_CORRECTIONS

var ICRF

var ITRF_CIO_CONV_1996_ACCURATE_EOP

var ITRF_CIO_CONV_1996_SIMPLE_EOP

var ITRF_CIO_CONV_2003_ACCURATE_EOP

var ITRF_CIO_CONV_2003_SIMPLE_EOP

var ITRF_CIO_CONV_2010_ACCURATE_EOP

var ITRF_CIO_CONV_2010_SIMPLE_EOP

var ITRF_EQUINOX_CONV_1996_ACCURATE_EOP

var ITRF_EQUINOX_CONV_1996_SIMPLE_EOP

var ITRF_EQUINOX_CONV_2003_ACCURATE_EOP

var ITRF_EQUINOX_CONV_2003_SIMPLE_EOP

var ITRF_EQUINOX_CONV_2010_ACCURATE_EOP

var ITRF_EQUINOX_CONV_2010_SIMPLE_EOP

var MOD_CONVENTIONS_1996

var MOD_CONVENTIONS_2003

var MOD_CONVENTIONS_2010

var MOD_WITHOUT_EOP_CORRECTIONS

var PZ90_11

var TEME

var TIRF_CONVENTIONS_1996_ACCURATE_EOP

var TIRF_CONVENTIONS_1996_SIMPLE_EOP

var TIRF_CONVENTIONS_2003_ACCURATE_EOP

var TIRF_CONVENTIONS_2003_SIMPLE_EOP

var TIRF_CONVENTIONS_2010_ACCURATE_EOP

var TIRF_CONVENTIONS_2010_SIMPLE_EOP

var TOD_CONVENTIONS_1996_ACCURATE_EOP

var TOD_CONVENTIONS_1996_SIMPLE_EOP

var TOD_CONVENTIONS_2003_ACCURATE_EOP

var TOD_CONVENTIONS_2003_SIMPLE_EOP

var TOD_CONVENTIONS_2010_ACCURATE_EOP

var TOD_CONVENTIONS_2010_SIMPLE_EOP

var TOD_WITHOUT_EOP_CORRECTIONS

var VEIS_1950

class Maneuver (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

Instance variables

var maneuver_params

Field Maneuver.maneuver_params

var maneuver_type

Field Maneuver.maneuver_type

var time

Field Maneuver.time

var trigger_event

Field Maneuver.trigger_event

var trigger_params

Field Maneuver.trigger_params

class ManeuverTrigger

Maneuver trigger events.

Class variables

var APSIDE_CROSSING

var DATE_TIME

var LATITUDE_CROSSING

var LATITUDE_EXTREMUM

var LONGITUDE_CROSSING

var LONGITUDE_EXTREMUM

var NODE_CROSSING

var UNDEFINED

class ManeuverType

Maneuver types.

Class variables

var ARG_PERIGEE_CHANGE

var CONSTANT_THRUST

var EAST_WEST_STATIONING

var ECCENTRICITY_CHANGE

var INCLINATION_CHANGE

var NORTH_SOUTH_STATIONING

var PERIGEE_CHANGE

var RAAN_CHANGE

var SEMI_MAJOR_AXIS_CHANGE

var STOP_PROPAGATION

var UNDEFINED

class Measurement (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

Instance variables

var angle_rates

Field Measurement.angle_rates

var station

Field Measurement.station

var time

Field Measurement.time

var true_state

Field Measurement.true_state

var values

Field Measurement.values

class MeasurementType

Measurement types.

Class variables

var AZIMUTH

var DECLINATION

var ELEVATION

var POSITION

var POSITION_VELOCITY

var RANGE

var RANGE_RATE

var RIGHT_ASCENSION

class OutputFlag

Bit flags that control propagation and estimation output.

Class variables

var OUTPUT_DENSITY

var OUTPUT_ECLIPSE

var OUTPUT_ESTM_COV

var OUTPUT_INNO_COV

var OUTPUT_PROP_COV

var OUTPUT_RESIDUALS

class Parameter (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

Instance variables

var estimation

Field Parameter.estimation

var max

Field Parameter.max

var min

Field Parameter.min

var value

Field Parameter.value

class PositionAngle

Orekit position angles.

Class variables

var ECCENTRIC

var MEAN

var TRUE

class Settings (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

var MeasurementsEntry

A ProtocolMessage

var StationsEntry

A ProtocolMessage

Instance variables

var drag_MSISE_flags

Field Settings.drag_MSISE_flags

var drag_coefficient

Field Settings.drag_coefficient

var drag_exp_H0

Field Settings.drag_exp_H0

var drag_exp_Hscale

Field Settings.drag_exp_Hscale

var drag_exp_rho0

Field Settings.drag_exp_rho0

var drag_model

Field Settings.drag_model

var estm_DMC_acceleration

Field Settings.estm_DMC_acceleration

var estm_DMC_corr_time

Field Settings.estm_DMC_corr_time

var estm_DMC_sigma_pert

Field Settings.estm_DMC_sigma_pert

var estm_covariance

Field Settings.estm_covariance

var estm_detection_probability

Field Settings.estm_detection_probability

var estm_filter

Field Settings.estm_filter

var estm_gating_probability

Field Settings.estm_gating_probability

var estm_gating_threshold

Field Settings.estm_gating_threshold

var estm_outlier_sigma

Field Settings.estm_outlier_sigma

var estm_outlier_warmup

Field Settings.estm_outlier_warmup

var estm_process_noise

Field Settings.estm_process_noise

var estm_smoother_iterations

Field Settings.estm_smoother_iterations

var geo_zone_lat_lon

Field Settings.geo_zone_lat_lon

var gravity_degree

Field Settings.gravity_degree

var gravity_order

Field Settings.gravity_order

var integ_abs_tolerance

Field Settings.integ_abs_tolerance

var integ_max_time_step

Field Settings.integ_max_time_step

var integ_min_time_step

Field Settings.integ_min_time_step

var integ_rel_tolerance

Field Settings.integ_rel_tolerance

var maneuvers

Field Settings.maneuvers

var measurements

Field Settings.measurements

var ocean_tides_degree

Field Settings.ocean_tides_degree

var ocean_tides_order

Field Settings.ocean_tides_order

var output_flags

Field Settings.output_flags

var prop_end

Field Settings.prop_end

var prop_inertial_frame

Field Settings.prop_inertial_frame

var prop_initial_TLE

Field Settings.prop_initial_TLE

var prop_initial_state

Field Settings.prop_initial_state

var prop_start

Field Settings.prop_start

var prop_step

Field Settings.prop_step

var rp_coeff_absorption

Field Settings.rp_coeff_absorption

var rp_coeff_reflection

Field Settings.rp_coeff_reflection

var rp_sun

Field Settings.rp_sun

var rso_area

Field Settings.rso_area

var rso_attitude_provider

Field Settings.rso_attitude_provider

var rso_facets

Field Settings.rso_facets

var rso_mass

Field Settings.rso_mass

var rso_solar_array_area

Field Settings.rso_solar_array_area

var rso_solar_array_axis

Field Settings.rso_solar_array_axis

var rso_spin_acceleration

Field Settings.rso_spin_acceleration

var rso_spin_velocity

Field Settings.rso_spin_velocity

var sim_measurements

Field Settings.sim_measurements

var solid_tides_moon

Field Settings.solid_tides_moon

var solid_tides_sun

Field Settings.solid_tides_sun

var stations

Field Settings.stations

var third_body_moon

Field Settings.third_body_moon

var third_body_sun

Field Settings.third_body_sun

class Station (*args, **kwargs)

A ProtocolMessage

Ancestors

• google.protobuf.pyext._message.CMessage
• google.protobuf.message.Message

Class variables

var DESCRIPTOR

Instance variables

var altitude

Field Station.altitude

var bias

Field Station.bias

var bias_estimation

Field Station.bias_estimation

var fov_aperture

Field Station.fov_aperture

var fov_azimuth

Field Station.fov_azimuth

var fov_elevation

Field Station.fov_elevation

var latitude

Field Station.latitude

var longitude

Field Station.longitude

class TDMFileFormat

CCSDS TDM file formats.

Class variables

var KEYVALUE

var UNKNOWN

var XML