Simulation of a guided launch with GuidedLaunch2DSim

The simulation ends at burnout. This is the same simulation used by LaunchGUI. The simulation allows you to scale the last stage of the vehicle.

See also: RocketDatabase, LaunchRHSData, GuidedLaunch2DSim, GuidedLaunch2DRHS

Contents

%--------------------------------------------------------------------------
%	  Copyright 2015 Princeton Satellite Systems, Inc.
%   All rights reserved.
%--------------------------------------------------------------------------

Demo of Pegasus air launch

rocket = RocketDatabase('pegasus');
d = LaunchRHSData(2,rocket);
d.rhsFun = @GuidedLaunch2DRHS;

fpa0  = 0.95;  % flight path angle (rad)
scale = 1;    % scale of last stage
coast = 0.5;  % minutes
angle = 3;    % degrees

% Desired mass and initial conditions
d.mDes = 400;
d.h0   = 12;   % km
d.v0   = 0.25; % km

First case: direct ascent

d.direct = 1;
params   = [fpa0 scale coast];

[time,xTraj,dD] = GuidedLaunch2DSim( params, d );

h = NewFig( 'Guided Launch: Direct' );
set(h,'position',[0,400,1120,420]);
subplot(1,2,1)
plot(xTraj(:,1),xTraj(:,2)), set(gca,'fontsize',14)
xlabel('Range [km]'), ylabel('Alt [km]')
hold on, axis equal, grid on
title(sprintf('FLIGHT TIME = %4.0f SEC',time(end)))
subplot(1,2,2), set(gca,'fontsize',14)
ax = plotyy(time',xTraj(:,3)',time',xTraj(:,4)');
grid on, hold on
axes(ax(1))
xlabel('Time [s]'), ylabel('V [km/sec]')
axes(ax(2))
ylabel('Gamma [rad]')
title(sprintf('V_{BO} = %2.2f KM/SEC, GAMMA_{BO} = %2.1f DEG',xTraj(end,3),xTraj(end,4)*180/pi));

Plot2D(time',xTraj(:,5:7)','Time (s)',{'1','2','3'},'Fuel Mass (kg)')

Second case: indirect launch

d.direct = 0;
params   = [fpa0 scale angle*pi/180];

[time,xTraj,dID] = GuidedLaunch2DSim( params, d );

h = NewFig( 'Guided Launch: Indirect' );
set(h,'position',[0,400,1120,420]);
subplot(1,2,1)
plot(xTraj(:,1),xTraj(:,2)), set(gca,'fontsize',14)
xlabel('Range [km]'), ylabel('Alt [km]')
hold on, axis equal, grid on
title(sprintf('FLIGHT TIME = %4.0f SEC',time(end)))
subplot(1,2,2), set(gca,'fontsize',14)
[ax,H1,H2] = plotyy(time',xTraj(:,3)',time',xTraj(:,4)');
grid on, hold on
axes(ax(1))
xlabel('Time [s]'), ylabel('V [km/sec]')
axes(ax(2))
ylabel('Gamma [rad]')
title(sprintf('V_{BO} = %2.2f KM/SEC, GAMMA_{BO} = %2.1f DEG',xTraj(end,3),xTraj(end,4)*180/pi));

Plot2D(time',[xTraj(:,end)';(xTraj(:,4)+xTraj(:,end))']*180/pi,'Time [s]',...
  {'Control (\alpha)','Total Angle (\gamma + \alpha)'},'Thrust Angle from Horizonal (deg)')


Figui

%--------------------------------------

Published with MATLAB® R2020a