Navigation¶

struct nmeasim::core::model::Navigation · Library API

Position, motion and heading of the vessel.

#include <nmeasim/core/model/vessel_state.hpp>

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp (line 75)

Magnetic quantities are derived, not stored: true = magnetic + variation for the heading and the course over ground, and magnetic = compass + deviation for the heading read from the ship's compass.

Summary¶

Public member functions

Name	Description
`heading_magnetic_deg()`	Returns the heading referenced to magnetic north, as HDM, VHW and Signal K send it.
`heading_compass_deg()`	Returns the heading as the ship's compass reports it, as HDG sends it.
`course_over_ground_magnetic_deg()`	Returns the course over ground referenced to magnetic north.

Public data members

Name	Description
`position`	`Position` of the GNSS antenna, the reference point of the AIS dimensions.
`altitude_m`	Antenna altitude above mean sea level, sent in GGA and Signal K; negative below it.
`course_over_ground_deg`	Course over ground in degrees true, in [0, 360); sent in RMC, VTG, VBW and AIS.
`speed_over_ground_kn`	Speed over ground, not negative; sent in RMC, VTG, VBW and the AIS position report.
`heading_true_deg`	Heading of the bow in degrees true, in [0, 360); sent in HDT, VHW and AIS.
`magnetic_variation_deg`	Magnetic variation of the chart position, positive east, sent in RMC and HDG.
`magnetic_deviation_deg`	Deviation of the ship's compass, positive east, sent in HDG; it applies to the compass heading only.
`speed_through_water_kn`	Speed through the water along the heading, not negative; sent in VHW and VBW.
`rate_of_turn_deg_per_min`	Rate of turn, positive to starboard (heading increasing), sent in ROT and AIS.

Public member functions¶

heading_magnetic_deg()¶

double heading_magnetic_deg() const noexcept

Returns the heading referenced to magnetic north, as HDM, VHW and Signal K send it.

Deviation does not apply: it is an error of the ship's compass, which heading_compass_deg() includes.

Returns double: heading_true_deg - magnetic_variation_deg, normalised to [0, 360).

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:102 · defined in src/core/src/model/vessel_state.cpp:10

heading_compass_deg()¶

double heading_compass_deg() const noexcept

Returns the heading as the ship's compass reports it, as HDG sends it.

Returns double: heading_true_deg - magnetic_variation_deg - magnetic_deviation_deg, normalised to [0, 360).

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:108 · defined in src/core/src/model/vessel_state.cpp:14

course_over_ground_magnetic_deg()¶

double course_over_ground_magnetic_deg() const noexcept

Returns the course over ground referenced to magnetic north.

Deviation does not apply: the course comes from the GNSS receiver, not the compass.

Returns double: course_over_ground_deg - magnetic_variation_deg, normalised to [0, 360).

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:115 · defined in src/core/src/model/vessel_state.cpp:19

Public data members¶

position¶

geo::Position position

Position of the GNSS antenna, the reference point of the AIS dimensions.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:77

altitude_m¶

double altitude_m{0.0}

Antenna altitude above mean sea level, sent in GGA and Signal K; negative below it.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:79

course_over_ground_deg¶

double course_over_ground_deg{0.0}

Course over ground in degrees true, in [0, 360); sent in RMC, VTG, VBW and AIS.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:81

speed_over_ground_kn¶

double speed_over_ground_kn{0.0}

Speed over ground, not negative; sent in RMC, VTG, VBW and the AIS position report.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:83

heading_true_deg¶

double heading_true_deg{0.0}

Heading of the bow in degrees true, in [0, 360); sent in HDT, VHW and AIS.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:85

magnetic_variation_deg¶

double magnetic_variation_deg{0.0}

Magnetic variation of the chart position, positive east, sent in RMC and HDG.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:87

magnetic_deviation_deg¶

double magnetic_deviation_deg{0.0}

Deviation of the ship's compass, positive east, sent in HDG; it applies to the compass heading only.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:90

speed_through_water_kn¶

double speed_through_water_kn{0.0}

Speed through the water along the heading, not negative; sent in VHW and VBW.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:92

rate_of_turn_deg_per_min¶

double rate_of_turn_deg_per_min{0.0}

Rate of turn, positive to starboard (heading increasing), sent in ROT and AIS.

Declared in src/core/include/nmeasim/core/model/vessel_state.hpp:94