| Supported by the 12th Five-Year National Science-technology Support Plan Projects "Study on Rural Spatial Planning Geographic Information Satellite Fast Height Measurement and Accurate Positioning", Considering the positioning error will diverge over time, when locating in the shadowed areas for satellite signals, with the full use of precise positioning offline and "halt-measure-move arbitrarily" of inertial measurement system, this paper focuses on the research of the inertial positioning error suppression technology based on cadastral surveying. The main work in this paper are as follows:(1) The influence of direction cosine algorithm, quaternion algorithm and rotation vector attitude algorithm on the positioning error of the inertial measurement system used in cadastral survey is studied. Firstly, the attitude and positioning accuracy of the three algorithms are simulated based on the conical motion, which is also verified by the actual experimental data. Based on the Amplitude-Frequency characteristics by Fourier transform, combined with the simulation conclusion, the experimental results are analyzed and explained.(2) With the known velocity and attitude information at coordinates points, the error estimation of inertial sensors is studied. Based on the system state equation and observation equation of inertial measurement system, the degree of observability of system state variables is analyzed. Meanwhile, the error estimation result of inertial sensors using Kalman filter and Two-Filter smoother is compared and the simulation results are verified by the experiment data collected by the turntable.(3) Considering that it is allowed to precisely position offline for the cadastral surveying, a method for measuring the position of the point based on bidirectional-time calculation is proposed. Firstly, the outside measurement procedure and the inside data processing method based on bidirectional-time calculation is described, and the attitude angle variation curve of inertial measurement system in actual measurement experiment is constructed by Cubic Spline Interpolation, besides, the simulation analysis of the locating method of the point based on bidirectional-time calculation is carried out, finally, the effectiveness of the method is verified by the actual measurement experiment.(4) The Zero Velocity Update for cadastral surveying is studied. firstly, the correction effect of the Zero Velocity Update based on quadratic curve fitting is simulated, besides, the influence of time interval on the correction effect is analyzed and compared, finally, the simulation results are verified by the experiment data collected by the turntable. |
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