Knowra Orientation Orientation Orientation is the rotational attitude of an object relative to a reference frame. It specifies how the object's axes or directions are aligned, independently of its position.
Rotation matrix : A square matrix that represents a linear transformation, including rotations of coordinate frames. It maps an object's axes into a reference frame and composes orientations through matrix multiplication.
Reference frame : A coordinate system, with an origin and defined axes, used to describe positions and directions. Orientation is always stated relative to axes chosen by a reference frame.
Attitude determination : The estimation of a vehicle's orientation relative to a reference frame from sensor measurements. Spacecraft use it to infer their attitude from stars, the Sun, or other observations.
Pose : The complete spatial configuration of an object, including its position and orientation. Pose combines orientation with position, whereas orientation alone omits location.
Euler angles : A set of three angles that represents a three-dimensional rotation as successive rotations about specified axes. They describe orientation compactly, but their values depend on rotation order and axis convention.
Rigid body : An idealized body whose internal distances remain fixed during motion. A rigid body's orientation can be described by how its fixed body axes align with a frame.
Inertial measurement unit : An instrument combining accelerometers and gyroscopes to measure specific force and angular motion. Its angular-rate measurements support estimates of changing orientation.
Angular velocity : The rate at which an object's orientation changes, expressed as a vector or equivalent quantity. Angular velocity describes change over time, not the attitude at a particular instant.
Quaternion : A number system extending complex numbers with three imaginary components, often used to represent three-dimensional rotations. Unit quaternions encode orientation without the singularities that affect Euler angles.
Degrees of freedom : The number of independent parameters needed to specify a system's configuration. A free rigid body's orientation in three dimensions has three degrees of freedom.
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