Proceedings International Workshop on Mobile Mapping Technology

li, rongxing

Bibliographic data

Monograph

Persistent identifier:: 856671290

Author:: Li, Rongxing

Title:: Proceedings International Workshop on Mobile Mapping Technology

Sub title:: April 21 - 23, 1999, Bangkok, Thailand

Scope:: 1 Online-Ressource (Getr. Zählung [ca. 400 Seiten])

Year of publication:: 1999

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856671290

Illustration:: Illustrationen, Diagramme, Karten

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Session 3: Kinematic Real-time Positioning]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: Airborne Mapping System with GPS-supported Aerotriangulation. Deren Li, Xiuxiao Yuan.

Document type:: Monograph

Structure type:: Chapter

3. WuCAPS^ DESCRIPTION According to the principle mentioned above, the authors developed a software package suitable for the combined adjustment of photogrammetric and non- photogrammetric observations—WuCAPS G/ >s. It starts from collinearity equations, combines the stochastic model based on statistic theory with strict mathematical model of combined bundle adjustment, and then a series of special algorithms has been developed in WuCAPS GPS . The strictness of theory and the flexibility of practical use have indicated sufficiently that WuCAPS G/ > 5 will be widely used both in scientific research and in productive project. At present, WuCAPS Gra is using as means of the control point determination for aerial photogrammetry in China. WuCAPS G /> 5 consists of a group of separate program modules related to each other, which are written in FORTAN. It nearly contains all kinds of basic computation tasks on analytical aerotriangulation, and each task can be executed independently with result output, which is the prerequisite for WuCAPS G/ > 5 to be used in teaching and training. WuCAPS Gra is divided into two parts, i.e. a main system of combined bundle block adjustment for productive purpose and a subsystem of quality analysis to serve mainly as the purpose of some special scientific research. Figure 2 pictures the overview of the design for combined bundle block adjustment procedure in WuCAPS G /> 5 . WuCAPSgps includes the following basic functions: □ Block adjustment by strips This is a block adjustment program with a nonlinear correcting model based on quadratic conformal polynomial expression. It can meet the demands for topographic mapping at small or medium scale and severe the purpose of low precision point determination. □ Bundle block adjustment with additional parameters This is a conventional bundle adjustment program for pure photogrammetric observations. Three sets of self-calibration models, such as Bauer model with 3 parameters, Ebner model with 12 parameters and Brown model with 18 parameters [Wang, 1990], are alternative in the different photogrammetric projects. □ Combined bundle block adjustment with navigation data and/or geodetic observations This is the core function of WuCAPS G/ > 5 software package. If the original geodetic observations and/or the other auxiliary data as well as some relative constrains in object space are introduced into the mathematical rriodels of the conventional photogrammetric adjustment, the integral adjustment method is called combined adjustment in photogrammetry, which improves the location accuracy of photogrammetric points or reduces the number of the essential ground control points. In WuCAPS Gra the usable additional measurements include 3D GPS-determined positions of camera centers, INS-determined attitudes of camera, and the geodetic observations such as leveling, spatial distances, horizontal angles and vertical angles, and so on. □ Compensation of systematic errors It is well known that the accuracy of the conventional bundle adjustment has closed connection with the magnitude of the systematic errors in image observations. Therefore, during the combined bundle adjustment procedure, WuCAPS G />s can correct the systematic errors of photo observations by affine transformation (six parameters) using four fiducial marks, correcting formula of radial distortion according to the calibration report and self-calibration techniques, and compensate that of 3D GPS-determined coordinates of camera perspective centers in a linear correcting model. In addition, according to the coordinate residuals of the ground control points between from photogrammetric adjustment and from field survey, the adjusted coordinates of photogrammetric points can register with the coordinate system defined by the ground control points by least squares collocation after the conventional bundle adjustment. □ Automatic detection and rejection of the blunders Gross errors in observations are not avoidable in photogrammetry. An advanced adjustment program should automatically be able to detect and eliminate the blunders to obtain reliable computing results. For this purpose, several methods of blunder detection are used in WuCAPS g/ »5. The blunders in the fiducial mark observations are detected by data snooping approach [Forstner, 1985] during the inner orientation. The blunders in image observations are eliminated efficiently by varying weight iteration method [Wang, 1990] during the procedure of forming free strips and by Danish method [Kubik, 1982] in the combined bundle block adjustment, respectively. The gross errors including the ground control points and GPS- determined positions of the cameras are automatically detected by varying weight iteration method during the procedure of data preparation, too. □ Calculation for accuracy matrix of unknowns and reliability matrix of observations Accuracy and reliability are two very important factors to evaluate the quality of the adjusted results for photogrammetric block adjustment. Only results with high-accuracy and high- reliability are acceptable. Therefore, two 3-5-5

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