Experiment Development of Control Point Positioning Based on RTK

Abstract

This paper has a detailed introduce on parts of differential GPS system and construction method in control point positioning experiment .This paper also solves some problems, such as excluded from multipath interference. This paper focuses on analyzing the result accuracy of RTK positioning method. This experiment can eventually achieve the positioning accuracy is 2 centimeters or so. Obtain Standard coordinates of base station & control point and select the experimental field Before the start of the experiment, put the GPS receiver in the base station and the control point, use the GPS single point positioning method for positioning, get a set of positioning information every one second and lasted one hour. Research shows that the error of single point GPS positioning obeys Gauss distribution, calculate the average value of all the obtained positioning information, this average value can be considered as the exact coordinate information of the measured position. The error judgment can be carried out by comparing the results of differential GPS positioning with the obtained exact coordinate information in the following experiment. In the experiment operation, in order to improve the reliability of base station data and ensure that the base station and the user station can receive more and the same satellite signal at the same time, the base station is located in a higher position generally and there is no obstruction all around. In the process of experiment, positioning experiments were carried out respectively many times at four positioning points in different height and different obstruction. (This four positioning points are: the roof platform of the second floor, the roof platform of the sixth floor, the courtyard hanging ladder of the sixth floor and the roof platform of the eleventh floor in the new main building) Compared with experimental data at this four positioning points, about 17 satellites positioning signal can be received at the roof platform of the eleventh floor in the new main building, there are many signals in this positioning point, so the reliability of the experimental result is the highest. In addition, this position is open around and there is no shielding effect of the surrounding buildings, therefore multipath effect errors can be effectively avoided. So select the eleventh roof platform of the new main building as the formal experimental field and carry out the control point positioning experiment.