Research On High Precision Positioning And Orientation Method For Long Distance Horizontal Drilling

With the development of China,underground long distance horizontal orientation in deep and offshore drilling and urban pipeline survey has become an important research direction.In underground orientation,the first thing to solve is the navigation problem.As passive and autonomous navigation,inertial navigation is the first choice for drilling positioning and pipeline survey.Due to the divergence of inertial navigation errors over time,inertial/odometer/landmark/magnetic mark and other multi-source information fusion positioning methods are often adopted for underground or pipeline positioning under general working conditions.The method of multi-source information fusion can improve the adaptability of the system.In the tunnel drilling environment such as Sichuan-Tibet railway,the location instrument is greatly affected by vibration.And the pipe is a closed long distance straight line,resulting in the coupling of error states and weak observability of the integrated navigation filter,which brings difficulties to the filter design.At the same time,there is no auxiliary landmark information along the line,only one position information can be used at the starting and ending point of the survey line.In order to meet the requirements of high precision positioning and orientation for kilometer-level drilling,this paper designs a positioning and orientation instrument for drilling based on SINS/OD integrated navigation technology.In order to achieve the positioning index of the system,this paper proposes a SINS/OD/landmark combination algorithm,and carries out in-depth research on the precision analysis of device selection,observability optimization of the combination algorithm,and odometer calibration with limited landmarks.The main research work and achievements are as follows:1.Based on covariance analysis method,the influence of constant zero bias and random angular walk of gyro on navigation accuracy is analyzed,and the relationship between them and position error is established,and the model is verified by simulation.The results show that the gyro bias must be less than 0.03°/ h in order to achieve the positioning accuracy of 1000-meter drilling better than 0.5%D.2.A SINS/OD/landmark model is proposed.By analyzing the observability of the integrated navigation state model,the state model is simplified to 15 states.At the same time,the measurement information is enlarged and the high precision positioning and orientation is realized by combining with RTS interval smoothing technology.The results show that the positioning error of 1000-meter drilling is less than 0.5%D.3.A scheme to obtain terminal coordinates under finite landmarks is proposed.Aiming at the limitation of limited landmarks in drilling scenes,a combined algorithm model based on nonholonomic constraint(NHC),zero velocity update(ZUPT)and coordinate update(CUPT)was proposed,and the end point position was obtained in a short time by combining with RTS smoothing algorithm,which was used to realize the pre-calibration of odometer.The experimental results show that the positioning error of integrated navigation with the pre-calibration parameters obtained by this scheme is less than 0.5%D.