State specification

In WOLF YAML specification, states have to be defined for sensors, landmarks and the first frame of the trajectory. All states are specified in the same way, organized in a map defined with the state keys.

The keys P, O, V, I are used for positions, orientations, velocities and sensor intrinsics, respectively.

Inside each key, the corresponding state is specified including:

• value: the value of the state.

• prior/type: the type of prior for the state, which can be:

  • initial_guess just will take the value to initialize the state.

  • fix will avoid the state to be optimized by the solver.

  • factor will add an absolute factor to the state, allowing the solver to optimize it. It requires to add also factor_std to be filled with the vector of standard deviations (sqrt of the covariance matrix diagonal).

For example, the specification of the first frame of a 3D problem of the trajectory in the YAML configuration file could be as follows:

first_frame:
  P:
    value: [0, 0, 0]
    prior:
      mode: "fix"
  O:
    value: [0, 0, 0, 1]
    prior:
      mode: "factor"
      factor_std: [0.1, 0.1, 0.1]
  V:
    value: [0, 0, 0]
    prior:
      mode: "initial_guess"

Note

Remember that the YAML templates contains all the parameters of each class and a brief doc. You can start from the templates and modify them to suit your needs. See more information in the YAML schema section.