curryer.compute.pointing¶

Pointing related calculations.

@author: Brandon Stone

Attributes¶

logger

Classes¶

`OccultType`	Types of planetary occultation.
`PointingData`	Class for working with TIM pointing data.

Functions¶

`calc_cosine`(target_state, boresight_vector)	Calculate the cosine angle between a boresight vector and one or more
`boresight_dot_object`(instrument, target, ugps_times)	Calculate the cosine between an instruments boresight and target.
`check_fov`(ugps_times, instrument[, target, observer, ...])	Check if there was an FOV event at the specified time.
`check_occult`(ugps_times, observer[, target1, target2, ...])	Check if there was an FOV event at the specified time.
`legacy_instrument_dot_object`(...[, ...])	Calculate the cosine angle between an instrument's boresight and an

Module Contents¶

curryer.compute.pointing.logger¶

curryer.compute.pointing.calc_cosine(target_state, boresight_vector)¶

Calculate the cosine angle between a boresight vector and one or more state vectors. Vectors will be normalized (inplace).

Parameters:

target_state (numpy.ndarray) – Array of state vectors [N, 3] or [3].
boresight_vector (numpy.ndarray) – Boresight vector [3].

Returns:

Cosine values. Return is a scalar if target_state was a 1D array.

Return type:

float or numpy.ndarray

curryer.compute.pointing.boresight_dot_object(instrument, target, ugps_times)¶

Calculate the cosine between an instruments boresight and target.

Parameters:

instrument (str or sds_spice.spicierpy.obj.Instrument) – Instrument to calculate the cosine angles for. If an Instrument object, it must contain a “frame” and “spacecraft”. Otherwise they are inferred from the instrument string.
target (str or sds_spice.spicierpy.obj.Body) – Target ephemeris object (e.g., Earth, Sun).
ugps_times (int or list of ints or numpy.ndarray) – One or more uGPS times to calculate values at.

Returns:

Cosine angle between the boresight and target, in the instrument frame.

Return type:

float or numpy.ndarray

Notes

The boresight is retrieve from the instrument’s kernel (IK).

curryer.compute.pointing.check_fov(ugps_times, instrument, target='MOON', observer=True, correction='LT+S', allow_nans=False)¶: Check if there was an FOV event at the specified time.

class curryer.compute.pointing.OccultType¶

Bases: enum.IntEnum

Types of planetary occultation. See: https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/occult_c.html

TOTAL_TARGET1_BY_TARGET2 = -3¶

ANNULAR_TARGET1_BY_TARGET2 = -2¶

PARTIAL_TARGET1_BY_TARGET2 = -1¶

NO_OCCULT = 0¶

PARTIAL_TARGET2_BY_TARGET1 = 1¶

ANNULAR_TARGET2_BY_TARGET1 = 2¶

TOTAL_TARGET2_BY_TARGET1 = 3¶

curryer.compute.pointing.check_occult(ugps_times, observer, target1='MOON', target2='SUN', correction='LT')¶: Check if there was an FOV event at the specified time.

class curryer.compute.pointing.PointingData(observer, qf_map=None, with_geolocate=False, microsecond_cadence=None)¶

Bases: curryer.compute.abstract.AbstractMissionData

Class for working with TIM pointing data.

DEFAULT_CADENCE = 10000000¶

DEFAULT_QF_MAP¶

observer¶

qf_map¶

with_geolocate = False¶

max_deltat = 0¶

get_pointing(ugps_times)¶

Determine pointing values.

Parameters:: ugps_times (int or iter of int) – Determine pointing at 1 or more times (uGPS).
Returns:: Table of [?] at each time.
Return type:: pandas.DataFrame

curryer.compute.pointing.legacy_instrument_dot_object(spacecraft_to_eci_rotation, spacecraft_in_eci_state, object_in_eci_state, boresight_in_instrument_vector, spacecraft_to_instrument_rotation=None)¶

Calculate the cosine angle between an instrument’s boresight and an object (planet).

Parameters:

spacecraft_to_eci_rotation (numpy.ndarray) – Rotation matrix (3x3 or Nx3x3) from the spacecraft’s reference frame to the ECI (earth centered inertial) reference frame.
spacecraft_in_eci_state (numpy.ndarray) – State vector (3 or Nx3; x,y,z) of the spacecraft’s location in the ECI reference frame.
object_in_eci_state (numpy.ndarray) – State vector (3 or Nx3; x,y,z) of the object’s location in the ECI reference frame. The object is typically a planet. For example, the vector would be all zeros if the object was Earth.
boresight_in_instrument_vector (numpy.ndarray) – Pointing vector (3; x,y,z) of the instrument’s boresight, in the instrument’s reference frame (e.g., [1, 0, 0]).
spacecraft_to_instrument_rotation (numpy.ndarray, optional) – Rotation matrix (3x3) from the spacecraft’s reference frame to the instrument’s reference frame. Default assumes they are the same.

Returns:

Cosine angle based on the normalized dot product of the instrument boresight and the object’s state vector(s). The return is a scalar numpy float if spacecraft_to_eci_rotation was a 2D array, otherwise it’s a 1D array of floats.

Return type:

numpy.float64 or numpy.ndarray

Notes

ECI and J2000 are considered the same spatial reference frame.
Based on the java implementation in tim_processing:
src/java/processing/tim/pointing_data/TCTEPointingDataServer.java
Java implementation difference - A “Quat4d” & “Vector3d” transformation

includes a matrix transposition; likely a quaternion format difference.