Research On Accuracy Of Station-transfer And Its Influencing Factors

Transformation of coordinate systems is one of foundations of the surveyingscience, and its knowledge system is improving better and better. Researches in thetheories of coordinate transformation models and calculations of transformation pa-rameters are also being deepened. In the field of surveying and mapping, calculatingthe coordinate conversion accuracy is mainly to determine the coordinate transforma-tion models and algorithms. However, in the field of precision measurement, accuracyis an important indicator to assess a measurement system. For multi-station measure-ment system, only to grasp the distribution rule of station-transfer accuracy whenunifying the measurement data to the same coordinate system, could we control theoverall measurement accuracy of the system.In this paper, coordinate transformation model and calculations of transformationparameters which focusing on the problems of coordinate transformation in precisionmeasurement field is discussed. The method is proposed to establish the distributionmodel of station-transfer accuracy by using unequal accuracy least square estimationtheory, and its feasibility is validated. The main contents of this dissertation are de-scribed as follows:(1) The coordinate transformation model and calculations of transformation pa-rameters currently used are summarized. The application of the models and the influ-ence of the calculations of transformation parameters on station-transfer accuracy areanalyzed.(2) By using unequal accuracy least square estimation theory, a distributionmodel of the station-transfer accuracy is established. And by this model, a method isproposed to assess the station-transfer accuracy. The feasibility of this method isvalidated by experiments.(3) The distribution model of station-transfer accuracy is analyzed by controlledthe variables. By analyzing the distribution model of station-transfer accuracy, we canfind position error and geometric distribution of common points is the main influenc-ing factors of station-transfer accuracy. And the effect laws of position error, amount,intensive degree and layout of common points to the station-transfer accuracy isin-depth studied. The effective methods is proposed to improve the station-transfer accuracy targeted at these factors. And these methods can provide a theoretical basisfor the layout scheme of the common points in guiding the field measurement.(4) The station-transfer accuracy of laser tracker field measured data is analyzedusing the coordinate station-transfer accuracy distribution model proposed in this pa-per. And the station-transfer accuracy of the target point is effectively controlled byimproving its influence factors.