Advanced Navigation Technology Issues For Reusable Launch Vehicles

The Reusable Launch Vehicle (RLV) can effectively reduce the spacecraftlaunch costs. There are a number of approaches to advanced guidance navigationand control (GNC) that have the potential for achieving the goals of significantlyincreasing reusable launch vehicle safety/reliability and reducing the cost. High-precision navigation method which is a part of advanced GNC technology lays thefoundation of accomplishing the mission and safe landing.The object of this paper is a rocket powered RLV, the solutions and keytechnologies for the navigation of RLV are studied in the thesis. The main contentsinclude:The research status at home and aboard of RLV which focus on navigationsystem solutions and filtering method are analyzed. Kinematics and Dynamicsmodel of RLV are established which under the launch coordinates. Further more,standard trajectory is designed based on the angle of attack (AOA) profile planningin advance.The navigation system solutions of RLV are designed based on the analysis offlight parameters, environmental characteristics and research status. At the sametime, Strapdown inertial navigation system (SINS) model, the satellite navigationsystem (GPS) model, Doppler radar gun model and radar altimeter model areestablished. Inertial navigation system redundancy scheme optimization methodsare proposed which can achieve a balance in system reliability and economy. Bynumerical simulation, mathematical models of navigation equipments are verifiedand SINS optimal redundancy scheme is designed which can provide reference forhigh reliability and low cost navigation system design. Positioning and velocityaccuracy of GPS are emphatically analyzed which under different pseudorangemeasurement accuracy, different pseudorange rate measurement accuracy anddifferent geometric dilution of precision (GDOP). It can provide the basis forprecision pre-analysis of tight coupling SINS/GPS integrated navigation system.Dynamic adaptive kalman filtering algorithm has being in-depth studied. Thisalgorithm contains two parts: creating dynamic model and adaptive process basedon considerable measure of state. Dynamic model can improve filter adaptability to dynamic process. Adaptive process can improve the estimation accuracy andstability of the filter. In order to improve navigation accuracy during reentry, tightcoupling SINS/GPS integrated navigation system model has being established.Moreover according to the navigation system solutions, SINS/GPS/Radio integratednavigation system model has being established yet. According to numericalsimulation for dynamic adaptive kalman filter of integrated navigation system ofRLV, misadjustment and convergence of dynamic adaptive kalman filteringalgorithm has being analyzed and proved.Integrated navigation system simulation platform of RLV has being built whichbased on Matlab R2009b software. Simulation for conventional kalman filter,dynamic adaptive kalman filter and integrated navigation system in reentry backsection are carried out in this simulation platform to analysis the performance.Simulation results show that the stability and convergence of dynamic adaptivekalman filtering algorithm are strong which can apply to the design of high-precision navigation system. At the same time, navigation accuracy in reentry backsection has been analyzed by this simulation which shows that the navigationsystem solutions are reasonable and dynamic adaptive kalman filtering algorithm iseffective and correct. The research achievements of this paper which has a strongengineering application value can provide solutions and method reference to thedesign of navigation system of RLV.