<h2>AAS 99-140</h2>
<h2>GPS simulation and Analysis for Reusable Launch Vehicles Using a Commercial Available Matlab Toolbox                                             </h2>
<h4>J. LaMance*, M. Evans*, J. Fernandez**                                                                                                                                              </h4>
*Constell, Inc, **Orbital, Inc.                                                                                                                                           
<h2> Abstract </h2>
This paper will address the analysis, simulation, and data review process used in the X-34 program for development of the GPS portion of the navigation system. An emphasis on how MATLAB and the Constellation Toolbox were used to generate simulation, process data, and develop Differential GPS (DGPS) base station integrity monitoring software will be presented. X-34 flight test data and simulation results will be presented. Also, a discussion of the development of the Receiver Autonomous Integrity Monitoring (RAIM) and DGPS base station software will be presented where the Toolbox is used as an integral part of the software development and testing process.