voyager-tech / faux-sat Goto Github PK

Is your feature request related to a problem? Please describe.
Create unit tests for each script so any changes in the future can be quickly checked for correctness

Solution
Use pytest to write unit testing in tests folder of repo

Alternatives considered
Hypothesis considered for testing but doe's not fit that well with types of tests will be running. Will reevaluate in the future

Additional context
N/A

Affected Functions

• Transform_Coordinate/IAU-2000 Transforms

• Transform_Coordinate/IAU-FK5 Transforms

• Transform_State/TimeAdjust

Is your feature request related to a problem? Please describe.
Currently, all vales pulled from these sites are hard coded for one date, making the data inaccurate for any other date

Solution
Scrape relevant websites for needed information and use within the functions

Alternatives considered
N/A

Additional context
Relevant Websites:

• AA: TAI-UTC = ΔAT (sec) - http://maia.usno.navy.mil/ser7/tai-utc.dat
• EOPCO4: https://datacenter.iers.org/eop/-/somos/5Rgv/latest/223

Is your feature request related to a problem? Please describe.
Desire for users to have the option to use 2 of the following to determine step size and total steps for propagator to run:

• ToF
• Start / End Date
• Step Size
• Total Steps

Solution
Implement code that calculates step size and total steps from the information above

Alternatives considered
Leave current settings that require steps and step size as inputs

Is your feature request related to a problem? Please describe.
Need acceleration transformations for implementing an integrator/corrector propagator.

Solution
Using equations from Vallado's Fundamentals of Astrodynamics and Applications

Alternatives considered
Currently, have ITRF to GCRF transform with the IAU-76/FK5 reduction, but need a transform that more easily supports acceleration transformation in addition to radius and velocity

Additional context
N/A

Is your feature request related to a problem? Please describe.
Inform users of the inputs and outputs as well as expected functionality of the propagator script

Solution
Write a clear and concise docstring

Is your feature request related to a problem? Please describe.
Need acceleration transformations for implementing an integrator/corrector propagator.

Solution
Using equations from Vallado's Fundamentals of Astrodynamics and Applications

Alternatives considered
Currently, have ITRF to GCRF transform with the IAU-76/FK5 reduction, but need a transform that more easily supports acceleration transformation in addition to radius and velocity

Additional context
N/A

Is your feature request related to a problem? Please describe.
Currently, the code is copy-pasted wherever it is needed, would prefer to just be a callable function for simplicity

Solution
Create a callable function in transform_state.py

Be sure to replace all appearances of original code with function once written

Solution
Allow users to select which bodies they want these perturbations considered for and using Vallado Equations, implement into the Gauss-Jackson propagator.

Additional context
One of many perturbations that need to be written to fully simulate satellite propagation.

TODO:

• Find a way to scrape the web for ephemeris files of all supported bodies to be able to determine the distance between satellite and bodies
• Determine the distance between the satellite and any bodies
• Implement distance data into acceleration equation

Is your feature request related to a problem? Please describe.
Preferable to use arrays over matrices

Solution
Change all np.matrix declarations to np.array and test working

Alternatives considered
N/A

Additional context
Recommended change

Solution
Determine a gravity model and using Vallado Equations, implement into the Gauss-Jackson propagator.

Additional context
One of many perturbations that need to be written to fully simulate satellite propagation.

Describe the bug
Change each function to handle arrays as input and output arrays as well

Functions that need refactoring:

• julian2gregorian_date (JD2Gregorian)
• gregorian2julian_date (Gregorian2JD)
• convert_time (TimeAdjust)
• Keplerian2Perifocal
• Perifocal2Keplerian
• Keplerian2Cartesian
• Cartesian2Keplerian
• Cartesian2Perifocal
• Perifocal2Cartesian

Additional context
Part of the general overhaul to arrays #17

ALL scripts that are used by main.py need to be refactored since the propagator now runs on arrays

Solution
Using Vallado Equations, implement into the Gauss-Jackson propagator.

Additional context
One of many perturbations that need to be written to fully simulate satellite propagation.

Solution
Determine an atmosphere model or many for the user to select between and using Vallado Equations, implement into the Gauss-Jackson propagator.

Additional context
One of many perturbations that need to be written to fully simulate satellite propagation.

Is your feature request related to a problem? Please describe.
Need acceleration transformations for implementing an integrator/corrector propagator.

Solution
Using equations from Vallado's Fundamentals of Astrodynamics and Applications

Alternatives considered
Currently, have ITRF to GCRF transform with the IAU-76/FK5 reduction, but need a transform that more easily supports acceleration transformation in addition to radius and velocity

Additional context
Compare against other 3 models #2, #3, #4 and check for accuracy and speed tradeoffs.

• FK5_PolarMotion

• FK5_SiderealTime

• FK5_Nutation

• FK5_Precession

• FK5_ECFixed2J2000 - combine with backwards transform

• All are in Transform_Coordinate

Is your feature request related to a problem? Please describe.
Currently, the entire IAU-FK5 Transformation series is pretty ugly, due to being coded before I knew better techniques.

Solution
Will refactor to improve clarity and reduce file size.

Alternatives considered
N/A

Additional context
Need to go back through all 4 FK5 Transforms and the function that runs them all back to back

Is your feature request related to a problem? Please describe.
Need acceleration transformations for implementing an integrator/corrector propagator.

Solution
Using equations from Vallado's Fundamentals of Astrodynamics and Applications

Alternatives considered
Currently, have ITRF to GCRF transform with the IAU-76/FK5 reduction, but need a transform that more easily supports acceleration transformation in addition to radius and velocity

Additional context
N/A

Checklist

• Find coefficients for X/Y calculations from McCarthy & Petit (2003)