Observation.m

classdef Observation < handle 

%     _   _   _        _ _           _            
%    / \ | |_| |_ _ __(_) |__  _   _| |_ ___  ___ 
%   / _ \| __| __| '__| | '_ \| | | | __/ _ \/ __|
%  / ___ \ |_| |_| |  | | |_) | |_| | ||  __/\__ \
% /_/   \_\__|\__|_|  |_|_.__/ \__,_|\__\___||___/
%                                                 
properties 

    z;  % measurement
    R;  % covariance matrix of the measurement

end % properties

%  ____        _     _ _        __  __                _                                                             
% |  _ \ _   _| |__ | (_) ___  |  \/  | ___ _ __ ___ | |__   ___ _ __ ___                                           
% | |_) | | | | '_ \| | |/ __| | |\/| |/ _ \ '_ ` _ \| '_ \ / _ \ '__/ __|                                          
% |  __/| |_| | |_) | | | (__  | |  | |  __/ | | | | | |_) |  __/ |  \__ \                                          
% |_|    \__,_|_.__/|_|_|\___| |_|  |_|\___|_| |_| |_|_.__/ \___|_|  |___/                                          
%
% Even if Matlab do not provide an "easy" way to discriminate public and private member functions,
% here we firstly define the functions that are intended to be called in the main program                                                                                                                   
methods 

    function obj = Observation(landmark) % constructor

        obj.z   = to_column_vector(landmark);

        % Conversion to polar coordinates
        r       = norm(obj.z);
        theta   = atan2(obj.z(2), obj.z(1));
        
        % Jacobian of the transformation
        jac     = [ cos(theta), -r*sin(theta); ...
                    sin(theta),  r*cos(theta)];
        
        % Uncertainties
        Q       = zeros(2, 2);    % uncertainty in polar coordinates
        Q(1,1)  = 0.01;
        Q(2,2)  = 0.05 * pi / 180;
        obj.R   = jac * Q * jac';   % transformation to cartesian coordinates

    end
    

%  ____       _            _         __  __                _                   
% |  _ \ _ __(_)_   ____ _| |_ ___  |  \/  | ___ _ __ ___ | |__   ___ _ __ ___ 
% | |_) | '__| \ \ / / _` | __/ _ \ | |\/| |/ _ \ '_ ` _ \| '_ \ / _ \ '__/ __|
% |  __/| |  | |\ V / (_| | ||  __/ | |  | |  __/ | | | | | |_) |  __/ |  \__ \
% |_|   |_|  |_| \_/ \__,_|\__\___| |_|  |_|\___|_| |_| |_|_.__/ \___|_|  |___/
%
% Here are defined auxiliary functions used in the public members or for other simpler computations



end % methods
end % Laserscan class