Main Content

insCreateMotionModelTemplate

Create template file for motion model

Description

example

insCreateMotionModelTemplate(name) creates a template class file of a motion model to be used with the insEKF filter object. The function opens the file in the MATLAB® editor. The name argument specifies the name of the class. Modify the class definition based on your application.

Examples

collapse all

Create a motion model template using the insCreateMotionModel object function. Specify the name of the class as newMotionModel.

insCreateMotionModelTemplate("newMotionModel")

In the MATLAB editor, an untitled file opens with its class definition. After modifying the class definition, save the class file and use an object of the class with the insEKF object.

classdef newMotionModel < positioning.INSMotionModel
    %newMotionModel Template for motion model using insEKF
    %   Customize this motion model and use it with the insEKF to fuse
    %   data.
    %
    %   Example:
    %       filt = insEKF(newMotionModel);
    %
    %   See also insEKF, positioning.INSMotionModel.

    %   Generated on 13-Mar-2022 11:25:13

    properties (Constant)
        State1Length = 1 % Length of motion model state State1
        State2Length = 2 % Length of motion model state State2
    end

    methods
        function s = modelstates(motion, opts)
            %modelstates Define the tracked states for this motion model
            %   MODELSTATES returns a struct which describes the
            %   states used by this motion model and tracked by the insEKF
            %   filter object. The field names describe the individual state
            %   quantities, and you can access the estimates of those
            %   quantities through the statesparts function. The values of
            %   the struct determine the size and default values of the
            %   state vector. The input OPTS is the insOptions object used
            %   to build the filter.
            %
            %   See also insEKF, positioning.INSMotionModel.

            % Preallocate a struct with fields State1 and State2.
            % Overwrite the fields with different default values if
            % needed.
            s = struct("State1", zeros(1, motion.State1Length, opts.Datatype), ...
                "State2", zeros(1, motion.State2Length, opts.Datatype));
        end

        function statesdot = stateTransition(motion, filt, dt, varargin)
            %stateTransition State transition for motion states
            %   STATETRANSITION returns a struct with identical fields
            %   as the output of the modelstates function. The
            %   returned struct describes the per-state transition function
            %   for the motion model states.
            %
            %   This function is called by the insEKF object FILT when the
            %   PREDICT method of the FILT function is called. The DT and
            %   varargin inputs are the corresponding inputs to the
            %   predict method of the insEKF object.
            %
            %   *** THIS METHOD IS OPTIONAL ***
            %   If you delete this method, the model states will be
            %   constant. In this case, also delete the
            %   stateTransitionJacobian method.
            %
            %   See also insEKF, positioning.INSMotionModel.

            % Set statesdot.State1 to the derivative of State1 with
            % respect to time. If State1 is constant overtime, leave the
            % following line unchanged.
            statesdot.State1 = zeros(1, motion.State1Length, "like", filt.State);

            % Set statesdot.State2 to the derivative of State2 with
            % respect to time. If State2 is constant overtime, leave the
            % following line unchanged.
            statesdot.State2 = zeros(1, motion.State2Length, "like", filt.State);
        end

        function dfdx = stateTransitionJacobian(motion, filt, dt, varargin)
            %stateTransitionJacobian Jacobian of the stateTransition function
            %   STATETRANSITIONJACOBIAN returns a struct with identical
            %   fields as modelstates and describes the Jacobian of the
            %   per-state transition function relative to the State
            %   property of FILT. Each field value of STATESDOT should be a
            %   M-by-numel(FILT.State) row vector, representing the partial
            %   derivatives of that field's state transition function
            %   relative to the state vector.
            %
            %   This function is called by the insEKF object FILT when the
            %   PREDICT method of the FILT function is called. The DT and
            %   varargin inputs are the corresponding inputs to the
            %   predict method.
            %
            %   *** THIS METHOD IS OPTIONAL ***
            %   If this method is not implemented, a numerical Jacobian
            %   will be used instead.
            %
            %   See also insEKF, positioning.INSMotionModel.

            N = numel(filt.State);

            dfdx.State1 = zeros(motion.State1Length, N, "like", filt.State);
            dfdx.State2 = zeros(motion.State2Length, N, "like", filt.State);

            % Create indexing
            s1idx = stateinfo(filt, "State1");
            s2idx = stateinfo(filt, "State2");

            % Uncomment the line below, and set dfdx.State1 to the
            % Jacobian of the stateTransition function with respect to
            % the State property of the filter object filt. Use s1idx to
            % index the columns of dfdx.State1.

            % % dfdx.State1(:,s1idx) =

            % Uncomment the line below, and set dfdx.State2 to the
            % Jacobian of the stateTransition function with respect to
            % the State property of the filter object filt. Use s2idx to
            % index the columns of dfdx.State2.

            % % dfdx.State2(:,s2idx) =
        end
    end
end

% [EOF]

Input Arguments

collapse all

Motion model class name, specified as a string scalar or a character vector.

Example: "myClass"

Data Types: char | string

Version History

Introduced in R2022b