Research On Error Suppression Technology Of Vehicle-borne Inertial Measuerement System For Real Estate Unit

Aiming at the shortcomings of the handheld strapdown inertial measurement system,such as high quality,low measurement efficiency and high labor cost,the vehicle-borne inertial measurement system is applied to the real estate measurement.Vehicle-borne inertial measurement system has a high center of gravity,which is greatly affected by random disturbances in the environment.In addition,during the travel of the vehicle,the uneven road surface(bumps,side slips,etc.)affects the sensor measurement environment,resulting in the change of the sensor output error.Based on the kinematics characteristics of the vehicle-borne inertial measurement system,an error suppression technology scheme of initial alignment on stationary base and alignment for marching is proposed,so as to improve the measurement accuracy of the system.The main research work of this paper includes the following aspects:(1)The kinematics model of vehicle-borne inertial measurement system is researched.The seven-degree-of-freedom kinematics equation of the vehicle-borne inertial measurement system is analyzed and established,and the excitation-response of four wheels on different roads is simulated.Then the motion state at the center of the vehicle is simulated to obtain the motion state information of the inertial measurement system installed at the center of the vehicle.The simulation analysis of the misalignment angle between the travel of the vehicle inertial measurement systems is provided,which provides a theoretical basis for the nonlinear filtering technology research.(2)The initial alignment of the stationary base of the vehicle-borne inertial measurement system is researched.The linear error model based on small misalignment angle and the nonlinear error model based on large misalignment angle are analyzed and established.Under different initial attitude errors,KF filter(Kalman filter)and UKF filter(Unscented Kalman filter)are applied for initial alignment simulation.The accuracy of the estimation of the misalignment angle under different initial attitude errors is compared between the two filtering algorithms.(3)The inter-travelling alignment of the vehicle-borne inertial measurement system is researched.For the characteristics of high dynamics and nonlinear enhancement between the travel,the UKF filter algorithm is used to carry out on the inter-travelling alignment.Considering the statistical characteristics of noise in the actual measurement process can not be accurately known,the simplified Sage-Husa adaptive UKF filter algorithm is introduced to adaptively estimate the covariance matrix of the observed noise,which improves the accuracy and stability of the inter-travelling alignment.(4)The methods of the initial alignment on stationary base and the inter-travelling alignment of the vehicle-borne inertial measurement system are experimentally validated.The effectiveness of the initial alignment filter method on static base is verified by the semi-physical experiment of the turntable.The effectiveness of the inter-travelling alignment algorithm is verified by the measurement experiment between the travel.