function [state_eq, obser_eq, Nx, Ny, Nu, NparSys, Nparam, NparID, dt, Ndata, Nzi, izhf, ...
             t, Z, Uinp, param, parFlag, x0, iArtifStab, StabMat] = mDefCase01(test_case)

% Definition of model, flight data, initial values etc.
% test_case = 1: Lateral-directional motion, nx=2, ny=5, nu=3, test aircraft ATTAS
%                states  - p, r
%                outputs - pdot, rdot, ay, p, r
%                inputs  - aileron, rudder, beta 
%
% Inputs
%    test_case    test case number
%
% Outputs
%    state_eq     function to code right hand sides of state equations       
%    obser_eq     function to code right hand sides of observation equations
%    Nx           number of states 
%    Ny           number of observation variables
%    Nu           number of input (control) variables
%    NparSys      number of system parameters
%    Nparam       total number of system and bias parameters
%    NparID       total number of parameters to be estimated (free parameters)
%    dt           sampling time
%    Ndata        total number of data points for Nzi time segments
%    Nzi          number of time segments (maneuvers) to be analyzed simultaneously
%    izhf         cumulative index at which the maneuvers end when concatenated
%    t            time vector
%    Z            observation variables: Data array of measured outputs (Ndata,Ny)
%    Uinp         input variables: Data array of measured input (Ndata,Nu)
%    param        initial starting values for unknown parameters (aerodynamic derivatives) 
%    parFlag      flags for free and fixed parameters
%    x0           initial conditions on state variables
%    iArtifStab   integer flag to invoke artificial stabilization
%                 = 0: No artificial stabilization
%                 > 0: Artificial stabilization (needs definition of StabMat)
%    StabMat      artificial stabilization matrix; (Nx,Ny); nonzero only for iArtifStab>0           
%

% Constants
d2r = pi/180;
r2d = 180/pi;

%----------------------------------------------------------------------------------------
% Model definition
state_eq   = 'xdot_TC01_attas_lat';     % function for state equations       
obser_eq   = 'obs_TC01_attas_lat';      % function for observation equations
Nx         = 2;                         % Number of states 
Ny         = 5;                         % Number of observation variables
Nu         = 3;                         % Number of input (control) variables
NparSys    = 15;                        % number of system parameters
Nparam     = NparSys + Nx + Ny;         % Total number of system and bias parameters
dt         = 0.04;                      % sampling time
iArtifStab = 0;                         % No artificial stabilization

disp(['Test Case = ', num2str(test_case)]);
disp('Lateral-directional motion, Nx=2, Ny=5, Nu=3, ATTAS')

%----------------------------------------------------------------------------------------
% Load flight data for Nzi time segments to be analyzed and concatenate 
load ..\flt_data\fAttasAilRud1;        % flight data file
Nzi  = 1;                              % Number of time segements (Maneuvers)
data = fAttasAilRud1;     

% Number of data points Ndata and cumulative index izhf
Ndata = size(data,1);
izhf  = Ndata;

% Generate new time axis
t = [0:dt:Ndata*dt-dt]';

% Observation variables: pdot, rdot, ay, p, r
Z = [data(:,17)*d2r data(:,19)*d2r data(:,3) data(:,7)*d2r data(:,9)*d2r];

% Input variables: aileron, rudder, beta, 
Uinp = [(data(:,29)-data(:,28))*0.5*d2r...
        data(:,30)*d2r...
        data(:,14)*d2r];
    
% Initial starting values for unknown parameters (aerodynamic derivatives) 
param = [-3.53744e+00;  4.75534e-01; -4.93279e+00;  0.73334e+00; -4.34076e+00;...
         -0.86939e-01; -1.69526e-01; -1.92049e-01; -0.74855e+00;  1.55155e+00;... 
          0.0364;       2.130;        0.740;        2.279;       -5.193;...
          0.02;         0.02;...
          0.02;         0.02;         0.02;         0.02;         0.02]; 
  
% Flag for free and fixed parameters
parFlag =ones(Nparam,1);               % All parameters being estimated
% parFlag = [1;  1;  1;  1;  1;...
%            1;  1;  1;  1;  1;... 
%            1;  1;  1;  1;  1;...
%            1;  1;...
%            1;  1;  1;  1;  1]; 

% Total number of free parameters
NparID = size(find(parFlag~=0),1); 

% Initial conditions on state variables p0, r0
x0 = [0; 0];       % Linear model with lumped bias parameters: Initial conditions
                   % reduce to zero, see Section 3.5.2, Eq. (3.29)

% Artificial stabilization matrix
StabMat    = zeros(Nx,Ny);