Effect incorrect points of the Local Geodetic Network at results of the adjustment

Abstract

When a new Local Geodetic Network (LGN) should be established, some “old” geodetic points with coordinates [XY] fromthe present point field are used and contemporaneously some necessary “new” points are established in the area of LGN. Theirapproximate coordinates [X°Y°] are determined using competent measurements and computations.If the coordinate determinations of new points are correct and the coordinates of old points are without points decompabilities,the new LGN with all properties can be correctly determined using a convenient adjustment.If new network–points are not correctly determined (some distances and angles badly measured, other injurious influences),the adjustment results are not acceptable. (large residuals V, large coordinate standard deviations ˆ, ˆ, X Y s s etc.). In such falls thereis necessary to search for causes of the bad results in the network-adjustment. Occurrence of such a situation can be found in big valuesof some quantities oi i i dL = L − L of the vector dL ( i L - measured quantities as distances, angles, …; oiL - their approximative values.The wrong (large) i dL will ambiguously identify in the adjustment the distances, angles and the corresponding approximativecoordinates, which are unacceptable.Such situations are characteristic for:• Least Squares Adjustment (LSA),• Iteratively Reweighted Robust LSA (IRRLSA),as they are applicable for identification of wrong results in the adjustments

Keywords

• Local Geodetic Network
• Method of least squares
• robust adjustment
• weight iteration adjustment