"""
The set of methods describing the provenance of the accuracy values
"""
enum accuracyDerivationType {
  """
  The accuracy values have been calibrated using real data to
  derive accuracy values for particular instruments given
  particular environmental conditions - i.e. accuracy values
  will in general vary over time for the same set of
  instruments.
  """
  DYNAMICALLY_CALIBRATED
  "The values have been set using engineering judgement."
  ESTIMATED
  """
  The accuracy values have been measured using some dynamic
  process that is able to estimate the current performance of
  the instruments in use.
  """
  MEASURED
  """
  The accuracy values have been calibrated using real data to
  derive fixed accuracy values for particular instruments.
  """
  STATICALLY_CALIBRATED
}

"""
A base type for classes that report the accuracy of navigational
measurements
"""
type navigationAccuracyType {
  """
  The provenance or method by which the accuracy values have
  been derived
  """
  derivation: accuracyDerivationType!
  """
  The accuracy (represented as one standard deviation) of the
  time value.
  """
  timeAccuracy: durationType!
}

"""
This is the set of instrument types and other means by which
navigation information can be derived.
"""
enum navigationDerivationKindType {
  """
  Information derived by fusing data from more than one of
  these types of derivation source.
  """
  COMPOSITE
  """
  Information derived from an instrument that measures the
  (subsurface) sea or air density to estimate depth or
  altitude.
  """
  DENSITY_SENSOR
  """
  Information derived from an instrument that exploits the
  Doppler effect to measure speed relative to the immediate
  environment, particularly water.
  """
  DOPPLER_LOG
  """
  Information derived from an instrument that exploits the
  electromagnetic dynamo effect (conductor moving through an
  electromagnetic field produces a proportional voltage) to
  measure speed relative to the immediate environment,
  particularly water.
  """
  EM_LOG
  """
  Information is estimated from previously measured values (e.
  g. dead-reckoning).
  """
  ESTIMATED
  """
  Information derived from instruments based on an Inertial
  Navigation System (e.g. Gyroscopes and Accelerometers)
  """
  INS
  """
  Navigation based on the intersection of hyperbolic curves
  derived from long wave radio signals from known ground
  stations with repeaters - e.g. LORAN B and C
  """
  LW_HYPERBOLIC_INTERSECT
  "Information has been derived using some other technology"
  OTHER_METHOD
  """
  Information derived from an instrument that measures the
  (subsurface) sea or air pressure to estimate depth or
  altitude.
  """
  PRESSURE_SENSOR
  """
  Information derived by sensing the Earth's gravitational
  and/or magnetic field and/or their gradients using single
  particle systems that exploit quantum effects.
  """
  QUANTUM_GEOLOCATION
  """
  Information derived from instruments based on an Inertial
  Navigation System that measures acceleration using single
  particle systems that exploit quantum techniques.
  """
  QUANTUM_INS
  """
  Information derived from a satellite-based navigation
  system (e.g. GPS and GLONASS)
  """
  SATELLITE
  """
  Information has been supplied by the user (e.g. manual
  entry from a non-integrated system).
  """
  USER_SUPPLIED
  """
  Information derived by sensing the external environment and
  resolving position and orientation with reference to
  external data such as charts (e.g. SLAM techniques).
  """
  VISUAL_GEOLOCATION
}