Class: Korba::Kep

Inherits:
Object
  • Object
show all
Includes:
OrbitUtils
Defined in:
lib/korba/kep.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from OrbitUtils

#deg_to_rad, #distance, #eccentric_anomaly, #height_at_apogee, #height_at_perigee, #normalize_deg, #normalize_rad, #path_angle, #rad_to_deg, #true_anomaly, #velocity

Constructor Details

#initialize(object_name:, epoch:, semi_major_axis:, eccentricity:, inclination:, ra_of_asc_node:, arg_of_pericenter:, mean_anomaly:) ⇒ Kep

Returns a new instance of Kep.



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# File 'lib/korba/kep.rb', line 10

def initialize(object_name:, epoch:, semi_major_axis:, eccentricity:, inclination:, ra_of_asc_node:, arg_of_pericenter:, mean_anomaly:)
  @object_name = object_name
  @epoch = epoch
  @semi_major_axis = semi_major_axis
  @eccentricity = eccentricity
  @inclination = inclination
  @ra_of_asc_node = ra_of_asc_node
  @arg_of_pericenter = arg_of_pericenter
  @mean_anomaly = mean_anomaly
end

Instance Attribute Details

#arg_of_pericenter ⇒ Object (readonly)

Returns the value of attribute arg_of_pericenter.



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# File 'lib/korba/kep.rb', line 8

def arg_of_pericenter
  @arg_of_pericenter
end

#eccentricity ⇒ Object (readonly)

Returns the value of attribute eccentricity.



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# File 'lib/korba/kep.rb', line 8

def eccentricity
  @eccentricity
end

#epoch ⇒ Object (readonly)

Returns the value of attribute epoch.



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# File 'lib/korba/kep.rb', line 8

def epoch
  @epoch
end

#inclination ⇒ Object (readonly)

Returns the value of attribute inclination.



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# File 'lib/korba/kep.rb', line 8

def inclination
  @inclination
end

#mean_anomaly ⇒ Object (readonly)

Returns the value of attribute mean_anomaly.



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# File 'lib/korba/kep.rb', line 8

def mean_anomaly
  @mean_anomaly
end

#object_name ⇒ Object (readonly)

Returns the value of attribute object_name.



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# File 'lib/korba/kep.rb', line 8

def object_name
  @object_name
end

#ra_of_asc_node ⇒ Object (readonly)

Returns the value of attribute ra_of_asc_node.



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# File 'lib/korba/kep.rb', line 8

def ra_of_asc_node
  @ra_of_asc_node
end

#semi_major_axis ⇒ Object (readonly)

Returns the value of attribute semi_major_axis.



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# File 'lib/korba/kep.rb', line 8

def semi_major_axis
  @semi_major_axis
end

Instance Method Details

#to_car ⇒ Object 



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# File 'lib/korba/kep.rb', line 21

def to_car
  # 特異点対応: inclinationが0（または極めて小さい）場合の処理
  is_equatorial = inclination.abs < 1e-10

  if is_equatorial
    # 赤道面内の場合、x軸を基準にする
    vector_omega = Vector[1.0, 0.0, 0.0]
    vector_m = Vector[0.0, 1.0, 0.0]
    vector_n = Vector[0.0, 0.0, 1.0]
  else
    vector_n = Vector[
      Math.sin(deg_to_rad(inclination)) * Math.sin(deg_to_rad(ra_of_asc_node)),
      -Math.sin(deg_to_rad(inclination)) * Math.cos(deg_to_rad(ra_of_asc_node)),
      Math.cos(deg_to_rad(inclination))
    ]
    vector_omega = Vector[Math.cos(deg_to_rad(ra_of_asc_node)), Math.sin(deg_to_rad(ra_of_asc_node)), 0.0]
    vector_m = vector_n.cross(vector_omega)
  end

  r_angle_factor = deg_to_rad(arg_of_pericenter + true_anomaly)
  vector_r = distance * (Math.cos(r_angle_factor) * vector_omega + Math.sin(r_angle_factor) * vector_m)
  v_angle_factor = deg_to_rad(arg_of_pericenter + true_anomaly - path_angle)
  vector_v = velocity * (-Math.sin(v_angle_factor) * vector_omega + (Math.cos(v_angle_factor)) * vector_m)

  # NOTE: こっちでもいい
  # factor_matrix = Matrix[[Math.cos(deg_to_rad(ra_of_asc_node)), -Math.sin(deg_to_rad(ra_of_asc_node)) * Math.cos(deg_to_rad(inclination))],
  #                        [Math.sin(deg_to_rad(ra_of_asc_node)), Math.cos(deg_to_rad(ra_of_asc_node)) * Math.cos(deg_to_rad(inclination))],
  #                        [0, Math.sin(deg_to_rad(inclination))]] *
  #                 Matrix[[Math.cos(deg_to_rad(arg_of_pericenter)), -Math.sin(deg_to_rad(arg_of_pericenter))], [Math.sin(deg_to_rad(arg_of_pericenter)), Math.cos(deg_to_rad(arg_of_pericenter))]]
  # vector_r = Vector[*(factor_matrix * Matrix[[Math.cos(deg_to_rad(true_anomaly)) - eccentricity], [Math.sqrt(1 - eccentricity ** 2) * Math.sin(deg_to_rad(true_anomaly))]] * semi_major_axis).to_a.flatten]
  # vector_v = Vector[*(factor_matrix * Matrix[[-Math.sin(deg_to_rad(true_anomaly))], [Math.sqrt(1 - eccentricity ** 2) * Math.cos(deg_to_rad(true_anomaly))]] * Math.sqrt(Constant::GME * semi_major_axis) / vector_r.norm).to_a.flatten]

  Car.new(object_name:, epoch:, x: vector_r[0], y: vector_r[1], z: vector_r[2], vx: vector_v[0], vy: vector_v[1], vz: vector_v[2])
end