instrupy.basic_sensor_model — Basic Sensor Model

Description

This module provides the BasicSensorModel class which can be used to represent basic properties of an instrument. The BasicSensorModel object can be obtained from json/ dict representations using the from_json or from_dict functions. Please refer to basic sensor model for description of the instrument model and the expected key/value pairs.

Refer to the base module and OrbitPy coverage calculator module (orbitpy.coveragecalculator) to know how to use the BasicSensorModel object for coverage calculations.

The calc_data_metrics function can be used to calculate the data-metrics given the spacecraft-state and observed-location (target). The expected key/value pairs for the spacecraft-state input argument (of type dict) are:

Column	Data type	Units	Description
time [JDUT1]	float	JDUT1	Time in Julian Day UT1. Corresponds to the time of observation.
x [km], y [km], z [km]	float	km	Cartesian coordinates of satellite in EARTH_CENTERED_INERTIAL frame at the time of observation.
vx [km/s], vy [km/s], vz [km/s]	float	km/s	Velocity of spacecraft in EARTH_CENTERED_INERTIAL frame at the time of observation.

The expected key/value pairs for the observed-location input argument (of type dict) are:

Column	Data type	Units	Description
lat [deg], lon [deg]	float	degrees	Ground-point accessed (geocentric latitude, geocentric longitude).

Examples

1. Initializing a basic-sensor with 5 deg circular FOV geometry and aligned to spacecraft-body. Maneuver is possible within a 10 deg circular angular region. Unique identifier “bs1” is assigned.

   from instrupy.basic_sensor_model import BasicSensorModel
   
   bs1 = BasicSensorModel.from_json('{"name": "Atom", "mass":10, "volume":12.45, "dataRate": 40, "bitsPerPixel": 8, "power": 12, \
                                         "orientation": {"referenceFrame": "SC_BODY_FIXED", "convention": "REF_FRAME_ALIGNED"}, \
                                         "fieldOfViewGeometry": {"shape": "CIRCULAR", "diameter":5 }, \
                                         "maneuver":{"maneuverType": "CIRCULAR", "diameter":10} \
                                         "@id": "bs1"
                                                     }')
   

2. This example assumes the observer and the target location, and calculates the resulting viewing geometry. Note that none of the sensor parameters affect calculation of the viewing geometry directly. The parameters are used to determine if the target location can be viewed or not.

   from instrupy.basic_sensor_model import BasicSensorModel
   
   bs1 = BasicSensorModel.from_json('{}')
   epoch_JDUT1 =  2458543.06088 # 2019 Feb 28 13:27:40 is time at which the ECEF and ECI frames approximately align, hence ECEF to ECI rotation is identity. See <https://www.celnav.de/longterm.htm> online calculator of GMST.
   
   SpacecraftOrbitState = {'time [JDUT1]':epoch_JDUT1, 'x [km]': 6878.137, 'y [km]': 0, 'z [km]': 0, 'vx [km/s]': 0, 'vy [km/s]': 7.6126, 'vz [km/s]': 0} # altitude 500 km
   TargetCoords = {'lat [deg]': 0, 'lon [deg]': 0}
   obsv_metrics = bs1.calc_data_metrics(SpacecraftOrbitState, TargetCoords)
   
   print(obsv_metrics)
   
   >> {'observation range [km]': 500.0, 'look angle [deg]': 0.03, 'incidence angle [deg]': 0.03, 'solar zenith [deg]': 20.33}
   

API

Classes