Research On Positioning Technology Oriented To Real Estate Field Survey System

Supported by the special subject “Research on real estate investigation technology under the high precision requirement” of the Ministry of land and resources for the public welfare industry.Considering the lack of satellite signal and the positioning error will diverge over time,when locating in the shadowed areas,with the full use of "halt-measure-move arbitrarily" of real estate field survey system,combined with the high precision auxiliary information,the location technology of real estate field survey system is investigated.The main work in this thesis includes the following four aspects:1.The two-position alignment technology of real estate field survey system is investigated.With the known velocity and high precision horizontal attitude information,the state equation and observation equation of system are established.The degree of observability of system state variables is analyzed by using the method of singular value decomposition.Simulation analysis of single position alignment and two-position alignment is carried out by using Kalman filtering algorithm.2.The Zero Velocity Update Technology for real estate surveying is investigated.Aiming at the problem that the Zero Velocity Update based on quadratic curve fitting makes low use of the velocity during the stop interval of system,Gauss Process Regression Kernel Function is used to fit velocity error samples.The Ant Colony Optimization is used instead of Conjugate Gradient Method to search for the super parameter of Gauss Process Regression Kernel Function.A new Zero Velocity Update Technology based on Ant Colony-Gauss Process Regression curve fitting is proposed,and it is applied to the real estate surveying in the complete failure area of satellite.The simulation results show that the improved Zero Velocity Update Technology is more acuurate than the Zero Velocity Update based on quadratic curve fitting and the Zero Velocity Update based on Gauss Process Regression curve fitting.3.The GPS/SINS(Strapdown Inertial Navigation System)tightly integrated positioning technology for real estate surveying is investigated.In the weak satellite signals region,partial effective satellite and inertial measurement unit are used to form tightly integrated measurement mode.Aiming at the problem that CKF(Cubature Kalman Filtering)algorithm local volume point sampling is inaccurate and the system state mutation causes the filtering accuracy decreasing or even diverging in the high order nonlinear system,a new cubature point sampling rule is adopted to improve the accuracy of nonlinear function mapping,and then to improve the filtering accuracy.The fading factor of STF(Strong Tracking Filtering)is introduced to improve the robustness of the algorithm when the state changes suddenly.The improved CKF algorithm is applied to real estate surveying.The simulation results shows that the algorithm is effective for improving the accuracy of positioning.4.The location technology for real estate surveying is verified by experiments.The effectiveness of the two-position alignment is proved through simi-physical simulation experiments.The experiment data of the real estate surveying is used to verify the effectiveness of the positioning technology proposed in this thesis for real estate field survey system.