Study On Weighting Methods And Software Development In The Adjustment Of Engineering Control Network

The smooth development of every construction must be based on accurate control survey which is involved in the whole construction. The requirements for adjustment of control survey are also becoming higher and higher because of the complexity, accuracy and high standard of modern engineering. Weights of observations determines the stochastic model of adjustment system, and then greatly affects the whole adjustment system, but traditional method to get the weights can’t correctly reflect the actual precision of the control network, it may not be able to get satisfactory adjustment results and even has some adverse effects on the engineering quality. To reflect the actual situation of the control network more appropriately, to provide more exact and reliable data for the construction, it sounds reasonably to choose or improve the existing methods of deciding the weights, or develop a new method based on the actual precision of observation. So, the thesis mainly contains the following:Firstly, begining with the definition of weight, the classification of weight, the premise of deciding weights, the influence of weight error to adjustment, the traditional method of deciding weight and the test for uniform variance of stochastic model and so on, this thesis will systematically discusse the theory and method of deciding weight for adjustment of engineering control network, which shows importance of reasonable weighting to the adjustment calculation.Secondly, in the adjustment of leveling network, aimed at the influence of traditional weighting methods which do not concern much about the observation error of height caused by the terrain, this thesis proposed a new method of weighting for leveling network based on the difference of the elevation difference in back and forth measurements; in the adjustment of side-angular network and three dimensional network, it pointed out the shortage of actual observational precision which cannot be showed in traditional methods of weighting, and started from the differences of multi-observation data in horizontal direction and zenith angle, the thesis developed a new method of weighting based on the actual precision of observation.Then, the thesis respectively processed the observations data of common engineering control network in different weighting ways. According to analyzing the adjustment principles of different methods and making sorting comparison to the results, these new methods of weighting mentioned in this thesis have a better reflect to the actual situation of control network, an easier way to pass the test for uniform variance. Besides, it also made a comparison between two methods of weighting for the two dimensional adjustment in GPS control network, and pointed out that "program one" can gain both satisfactory adjustment results and more accurate assessed precision in common engineering.At last, based on the adjustment theory of general engineering control network, considering traditional ways of weighting and a series of new methods mentioned in this thesis, the thesis developed a adjustment software (ECNAS for short) for engineering control network using C#in the platform of Visual Studio2008. ECNAS can satisfy the requirements of adjustment calculation using multiple programs of weighting for any leveling network, conventional side-angular network, three dimensional network and any engineering GPS network. At the same time, ECNAS also provides functions such as checking data quality, test for uniform variance, drawing the graphics of control network and soon.