Micro GPS/INS Integrated Navigation Systems And Methods For Unmanned Helicopter Application

Unmanned control is realized through helicopter navigation information gained by its navigation system.And,integrated navigation combines more than two navigation module together,to get higher accuracy of navigation data by means of making best use of every advantages and bypassing potential disadvantages.However,existing unmanned helicopter platform,due to the engine,tail rotor,main rotor and other transmission mechanisms produce a variety of natural frequency of vibration noise,which causes interference to the sensitive measurement element on the aircraft platform.Therefore,a research focus on unmanned helicopter platform of satellite GPS/INS integrated navigation system and method aims at providing accurate navigation information to unmanned helicopter is necessary.This paper develops a hardware circuit with the LPC2368 controller and embedded real-time operating system based on uC/OS-II based on theory of Gradient Descent Method and the Extended Kalman Filter(EKF),after a study on both domestic and foreign research status and the laboratory of unmanned helicopter platform.Furthermore,it designs a filtering system directed against unmanned helicopter platform vibration,and accomplish attitude algorithm,as well as loose coupling integrated navigation solution based on Kalman algorithm.Firstly,it introduces the development of integrated navigation system,and the particularity of unmanned helicopter platform.It designs an integrated navigation system board based on the study of project group GPS and Inertial Navigation System(INS),and complete the work of onboard programming.Secondly,it studies the vibration characteristics of unmanned helicopter platform,analyzes the vibration frequency and vibration source.Thus a set of filtering method from the aspects of hardware,mechanical damping and software is designed to get the high quality of the metrical data accordingly.Thirdly,after a study on attitude algorithm of inertial navigation system and deviation amendment on nine axis installation,proportion and zero-offset information,use vector cross multiplication and gradient descent method successively to accomplish the attitude algorithm and to dynamically display on upper-computer.Finally,a state equation constructed by building a model of inertial navigation system deviation,and an observational equation through the position and velocity given by INS and GPS,send data into the extended Kalman filter for filtering processing.At last a position and velocity comparison between integrated navigation system output and GPS only is carried out,which shows that the integrated navigation system has a higher output frequency,higher accuracy and better fault-tolerant capability.