Module: Astronoby::Util::Astrodynamics

Defined in:
lib/astronoby/util/astrodynamics.rb

Class Method Summary collapse

Class Method Details

.eccentric_anomaly_newton_raphson(mean_anomaly, orbital_eccentricity, precision, maximum_iteration_count, current_iteration = 0, solution_on_previous_interation = nil) ⇒ Object

Source:

Title: Celestial Calculations
Author: J. L. Lawrence
Edition: MIT Press
Chapter: 4 - Orbits and Coordinate Systems



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# File 'lib/astronoby/util/astrodynamics.rb', line 12

def eccentric_anomaly_newton_raphson(
  mean_anomaly,
  orbital_eccentricity,
  precision,
  maximum_iteration_count,
  current_iteration = 0,
  solution_on_previous_interation = nil
)
  previous_solution = solution_on_previous_interation&.radians

  solution = if previous_solution.nil?
    if orbital_eccentricity <= 0.75
      mean_anomaly.radians
    else
      Math::PI
    end
  else
    previous_solution - (
      (
        previous_solution -
        orbital_eccentricity * Math.sin(previous_solution) -
        mean_anomaly.radians
      ) / (
        1 - orbital_eccentricity * Math.cos(previous_solution)
      )
    )
  end

  if current_iteration >= maximum_iteration_count ||
      (
        previous_solution &&
        (solution - previous_solution).abs <= precision
      )
    return Angle.from_radians(solution)
  end

  eccentric_anomaly_newton_raphson(
    mean_anomaly,
    orbital_eccentricity,
    precision,
    maximum_iteration_count,
    current_iteration + 1,
    Angle.from_radians(solution)
  )
end