Geodetic datums.
Geodetic and local datums that connect coordinate systems and gravity models to the Earth.
Classes:
| Name | Description |
|---|---|
GeodeticDatum |
Geodetic datum. |
LocalDatum |
Local datum. |
TopocentricDatum |
Topocentric datum class. |
VehicleDatum |
Vehicle datum class. |
Attributes:
| Name | Type | Description |
|---|---|---|
WGS84 |
World Geodetic System (WGS84) defining parameters and derived constants. |
|
ROTATION_NED_TO_ENU |
Rotation from NED to ENU topocentric coordinates. |
|
TRANSLATION_NED_TO_ENU |
Translation from NED to ENU topocentric coordinates (zero). |
|
TRANSFORM_NED_TO_ENU |
Rigid transform from NED to ENU topocentric coordinates. |
|
ROTATION_ENU_TO_NED |
Rotation from ENU to NED topocentric coordinates. |
|
TRANSLATION_ENU_TO_NED |
Translation from ENU to NED topocentric coordinates (zero). |
|
TRANSFORM_ENU_TO_NED |
Rigid transform from ENU to NED topocentric coordinates. |
|
ROTATION_FRD_TO_FLU |
Rotation from FRD to FLU local coordinates. |
|
TRANSLATION_FRD_TO_FLU |
Translation from FRD to FLU local coordinates (zero). |
|
TRANSFORM_FRD_TO_FLU |
Rigid transform from FRD to FLU local coordinates. |
|
ROTATION_FLU_TO_FRD |
Rotation from FLU to FRD local coordinates. |
|
TRANSLATION_FLU_TO_FRD |
Translation from FLU to FRD local coordinates (zero). |
|
TRANSFORM_FLU_TO_FRD |
Rigid transform from FLU to FRD local coordinates. |
module-attribute
¶
WGS84 = GeodeticDatum(
semimajor_axis=6378137.0,
flattening_factor=298.257223563,
angular_velocity=7.292115e-05,
gravitational_constant=398600441800000.0,
semiminor_axis=6356752.3142,
flattening=0.0033528106647475,
first_eccentricity=0.081819190842622,
first_eccentricity_squared=0.006694379990141,
second_eccentricity=0.082094437949696,
second_eccentricity_squared=0.006739496742276,
linear_eccentricity=521854.00842339,
normal_gravity_equator=9.7803253359,
normal_gravity_pole=9.8321849379,
normal_gravity_k=0.001931852652458,
normal_gravity_m=0.003449786506841,
)
World Geodetic System (WGS84) defining parameters and derived constants.
See Standard [07], Tables 3.1 - 3.7. Version: G1762.
module-attribute
¶
ROTATION_NED_TO_ENU = from_matrix(
[[0, 1, 0], [1, 0, 0], [0, 0, -1]]
)
Rotation from NED to ENU topocentric coordinates.
module-attribute
¶
TRANSLATION_NED_TO_ENU = from_identity()
Translation from NED to ENU topocentric coordinates (zero).
module-attribute
¶
TRANSFORM_NED_TO_ENU = from_rotation_translation(
ROTATION_NED_TO_ENU, TRANSLATION_NED_TO_ENU
)
Rigid transform from NED to ENU topocentric coordinates.
module-attribute
¶
Rotation from ENU to NED topocentric coordinates.
module-attribute
¶
Translation from ENU to NED topocentric coordinates (zero).
module-attribute
¶
Rigid transform from ENU to NED topocentric coordinates.
module-attribute
¶
ROTATION_FRD_TO_FLU = from_matrix(
[[1, 0, 0], [0, -1, 0], [0, 0, -1]]
)
Rotation from FRD to FLU local coordinates.
module-attribute
¶
TRANSLATION_FRD_TO_FLU = from_identity()
Translation from FRD to FLU local coordinates (zero).
module-attribute
¶
TRANSFORM_FRD_TO_FLU = from_rotation_translation(
ROTATION_FRD_TO_FLU, TRANSLATION_FRD_TO_FLU
)
Rigid transform from FRD to FLU local coordinates.
module-attribute
¶
Rotation from FLU to FRD local coordinates.
module-attribute
¶
Translation from FLU to FRD local coordinates (zero).
module-attribute
¶
Rigid transform from FLU to FRD local coordinates.
dataclass
¶
GeodeticDatum(
*,
semimajor_axis: float,
flattening_factor: float,
angular_velocity: float,
gravitational_constant: float,
semiminor_axis: float,
flattening: float,
first_eccentricity: float,
first_eccentricity_squared: float,
second_eccentricity: float,
second_eccentricity_squared: float,
linear_eccentricity: float,
normal_gravity_equator: float,
normal_gravity_pole: float,
normal_gravity_k: float,
normal_gravity_m: float,
origin: ArrayLike = (0.0, 0.0, 0.0),
prime_meridian: float = 0.0,
)
Geodetic datum.
Defines a datum for Earth. Two shape parameters are required for coordinate conversions/transforms and two mass and rotation parameters are required for gravity calculations. See Standard [07] for details.
Derived parameters
Four parameters are the theoretical minimum required to define a geodetic datum, however InertialSim requires additional derived parameters. Theoretically these derived parameters can be calculated from the four fundamental parameters but often they are specified explicitly to avoid losing numeric precision. See WGS84 as an example.
Geodetic origin support
InertialSim does not support geodetic datums with origin other than the center of mass of the Earth (0.0,0.0,0.0).
Prime meridian support
InertialSim does not support geodetic datums with prime meridians other than the IERS reference meridian, also known as the Greenwich meridian at 0.0 degrees longitude.
Attributes:
dataclass
¶
LocalDatum(*, axis_order: str)
Local datum.
Defines an axis ordering for a local coordinate system. Common examples are sensor and vehicle coordinate systems.
Attributes:
| Name | Type | Description |
|---|---|---|
axis_order |
str
|
|
dataclass
¶
TopocentricDatum(
*, axis_order: str = "NED", origin: Coordinates
)
Bases: LocalDatum
Topocentric datum class.
Defines a datum for a coordinate system with an origin on or near the surface of the Earth. Valid axis orderings are North (x), East (y), Down (z) (NED) or East (x), North (y), Up (z) (ENU). NED is the default.
Attributes:
| Name | Type | Description |
|---|---|---|
origin |
Coordinates
|
|
axis_order |
str
|
|
dataclass
¶
VehicleDatum(*, axis_order: str = 'FRD')
Bases: LocalDatum
Vehicle datum class.
Defines a datum for a coordinate reference system with an origin on a vehicle. Valid axis orderings are Forward (x), Right (y), Down (z): "FRD" or Forward (x), Left (y), Up (z): "FLU". FRD is the default.
Attributes:
| Name | Type | Description |
|---|---|---|
axis_order |
str
|
|