Class StaticWahbaAlignment
Defined in File StaticWahbaAlignment.hpp
Inheritance Relationships
Base Type
public navtk::inertial::StaticAlignment(Class StaticAlignment)
Class Documentation
A variation of StaticAlignment that compares average delta velocities and delta rotations measured on a stationary platform against simulated NED values of the same and determines the rotation between them via solve_wahba_svd().
Public Functions
Constructor.
- Parameters
model – The model of the inertial being aligned. Used in approximating the uncertainty of the orientation in the alignment solution.
align_time – The amount of IMU data that must be collected before calculating an alignment, in seconds. Once this threshold has been reached an alignment and covariance are calculated and status will change to AlignmentStatus::ALIGNED_GOOD. The type of imu available (ASPN_MEASUREMENT_IMU_IMU_TYPE_INTEGRATED or ASPN_MEASUREMENT_IMU_IMU_TYPE_SAMPLED) is assumed constant for all supplied imu data.
vel_cov – Initial covariance to attach to the stationary NED velocity.
Get the covariance associated with the computed alignment.
- Parameters
format – Format for the covariance block.
- Returns
A pair consisting of a boolean indicating usability of covariance, and the covariance itself. If no alignment has been computed (status != AlignmentStatus::ALIGNED_GOOD), then the bool is false and the covariance invalid. Otherwise the bool is true and the covariance is a block diagonal 9x9 Matrix of position covariance (m^2 NED), velocity covariance (m^2/s^2, NED), and tilt covariance (rad^2, NED). The position covariance is the covariance of all provided MeasurementPosition measurements, or in the case of only a single measurement being available, a copy of that measurements’ covariance field. Velocity covariance is fixed at 1e-4. The tilt covariance is a first-order approximation assuming only zero-mean constant biases on the IMU measurements based on the supplied ImuModel. Cross-terms between blocks are all 0.
Protected Functions
Do the actual alignment algorithm once sufficient data is available.
- Parameters
imu_time – Latest received IMU time, to be affixed to the generated solution.