Module: IERS::PolarMotion

Extended by:
EopParameter
Defined in:
lib/iers/polar_motion.rb

Defined Under Namespace

Classes: Entry

Constant Summary collapse

S_PRIME_RATE =

TIO locator rate in arcseconds per Julian century (IERS Conventions 2010, eq. 5.13)

-0.000047

Constants included from EopParameter

EopParameter::FLAG_TO_QUALITY

Class Method Summary collapse

Methods included from EopParameter

derive_quality, interpolate_field, resolve

Class Method Details

.at(input = nil, jd: nil, mjd: nil, interpolation: nil) ⇒ Entry

Parameters:

  • input (Time, Date, DateTime, nil) (defaults to: nil)
  • jd (Float, nil) (defaults to: nil) —

    Julian Date

  • mjd (Float, nil) (defaults to: nil) —

    Modified Julian Date

  • interpolation (Symbol, nil) (defaults to: nil) —

    +:lagrange+ or +:linear+

Returns:

Raises:



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# File 'lib/iers/polar_motion.rb', line 51

def at(input = nil, jd: nil, mjd: nil, interpolation: nil)
  query_mjd, window, method = resolve(
    input,
    jd: jd,
    mjd: mjd,
    interpolation: interpolation
  )

  x = interpolate_field(window, query_mjd, method) { |e| best_pm(e, :x) }
  y = interpolate_field(window, query_mjd, method) { |e| best_pm(e, :y) }

  Entry.new(
    x: x, y: y,
    mjd: query_mjd,
    data_quality: derive_quality(window, :pm_flag)
  )
end

.between(start_date, end_date) ⇒ Enumerator::Lazy<Entry>

Parameters:

  • start_date (Date)
  • end_date (Date)

Returns:

  • (Enumerator::Lazy<Entry>) 


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# File 'lib/iers/polar_motion.rb', line 83

def between(start_date, end_date)
  start_mjd = TimeScale.to_mjd(start_date)
  end_mjd = TimeScale.to_mjd(end_date)
  entries = Data.finals_entries

  EopLookup
    .range(entries, start_mjd, end_mjd)
    .lazy
    .map do |e|
      Entry.new(
        x: best_pm(e, :x),
        y: best_pm(e, :y),
        mjd: e.mjd,
        data_quality: EopParameter::FLAG_TO_QUALITY.fetch(
          e.pm_flag, :observed
        )
      )
    end
end

.rotation_matrix_at(input = nil, jd: nil, mjd: nil, interpolation: nil) ⇒ Array<Array<Float>>

Returns 3x3 polar motion rotation matrix.

Parameters:

  • input (Time, Date, DateTime, nil) (defaults to: nil)
  • jd (Float, nil) (defaults to: nil) —

    Julian Date

  • mjd (Float, nil) (defaults to: nil) —

    Modified Julian Date

  • interpolation (Symbol, nil) (defaults to: nil) —

    +:lagrange+ or +:linear+

Returns:

  • (Array<Array<Float>>) —

    3x3 polar motion rotation matrix

Raises:



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# File 'lib/iers/polar_motion.rb', line 75

def rotation_matrix_at(input = nil, jd: nil, mjd: nil, interpolation: nil)
  at(input, jd: jd, mjd: mjd, interpolation: interpolation)
    .rotation_matrix
end