Research On The Approach Of Position And Attitude Calibration Of Multi-sensor Integrated Mobile Measurement Equipment

With the advent of the era of intelligent surveying and mapping,the design and development of multi-sensor integrated vehicle-mounted mobile measuring equipment has been favored by the majority of surveyors.The calibration technology of the mobile measurement system is the main factor affecting the measurement accuracy of the multi-sensor integrated vehicle mobile measurement equipment.Pose calibration technology among sensors of mobile vehicle equipment plays a crucial role in whether mobile measurement system can realize rapid and accurate measurement of spatial geographic information.In the current measurement environment,due to the influence of multiple factors such as the sensor's own conditions,environmental factors and optimization methods,there are still some major problems in the calibration technology of on-board mobile measurement equipment,mainly manifested in the following aspects:(1)The calibration parameters of the vision system are affected by the changes of the parameters due to the continuous work of the sensor for a long time,so that the calibration results are unstable,the parameter flexibility is not high,and the calibration accuracy is low.(2)In the calibration of relative pose parameters of camera and inertial measurement unit,IMU drift and parameter calibration lack of adaptive constraints.(3)The multi-sensor integrated on-board system will produce vibration in the state of motion,which will change the relative position parameters between the multi-sensors to some extent,thus reducing the overall performance of the multi-sensor integrated on-board system,such as robustness and reliability.In this paper,we propose a set of high precision and adaptive constrained pose calibration method for multi-sensor integrated on-board mobile measuring equipment,focusing on the related theory,optimization model and precision analysis of the calibration technology for multi-sensor integrated on-board system.According to the binocular vision system parameters optimization method,the camera and the inertial measurement unit pose parameters adaptive calibration method,the multi-sensor collaborative space combination parameters calibration method,the multi-sensor integration vehicle system comprehensive evaluate accuracy and robustness analysis "the route of the in-depth research,the main research contents and innovation points are as follows:(1)Establish parameter optimization calibration model of binocular vision systemParameter optimization calibration method of binocular vision system is the key technology of multi-sensor integrated vehicle system calibration.Aiming at the problems of unstable calibration accuracy,low flexibility and lens distortion in the calibration of binocular vision,this paper adopts the parameter calibration method of binocular vision system,and establishes the imaging model,distortion correction model and parameter optimization calibration model of binocular vision.Through many experiments and analysis,the stable calibration results are obtained.(2)An adaptive calibration model for the pose parameters of the camera and the inertial measurement unit(IMU)was constructedAiming at the problems of random errors and non-uniform spatial distribution of errors,inertial measurement unit drift and lack of adaptive optimization of pose parameters,an adaptive constrained optimization calibration method for camera and inertial measurement unit pose parameters is proposed in this paper.Based on the pose parameter calibration model of the camera and the inertial measurement unit(IMU),the quaternion method and Newton method were used to construct the indirect adjustment equation with constraints to calculate the pose parameters of the camera and the IMU iteratively.The robustness and reliability of the proposed method are verified by experiments.(3)A collaborative calibration model of multi-sensor spatial position combination parameters was constructedThe coordinated calibration method of multi-sensor spatial position combination parameters is the key technology of multi-sensor integrated vehicle system calibration.Aiming at the independence,difference and lack of robustness of the sensors in the multi-sensor vehicle system,this paper builds a multi-sensor spatial position combination parameter collaborative calibration model,establishes the geometric and mathematical relationship between the corresponding spatial positions of various sensors,and realizes the overall optimization calibration of the multi-sensor vehicle system.Through experiments and robustness analysis,the repeatable plane accuracy and repeatable altitude accuracy of the multi-sensor vehicle system reached 0.055 m and 0.034 m.