【正文】 /(″)test 1 Std. 23 39 49 33 GPS 4 4 67 67 POS Std. 39 69 116 86 GPS 4 4 151 151 test 2 POS GPS 4 4 30 30 3 POS test 4 Std. 15 19 10 14 GPS 4 4 25 25 POS Note: 1) Std., GPS and POS stand that the exterior orientation elements are obtained by the method of standard AT with dense GCPs on the border,GPSsupported AT with 4 full GCPs on the corners and POS system, respectively (same to the following tables) . 2) Because the distribution of GCPs cannot meet the requirement of standard AT, for test 3 we cannot carry out the bundle block adjustment withdense GCPs on the border (same to the following tables). 3) RMS of check points’ residual is calculated from the error iΔ (i=X,Y,Z) between the adjusted coordinates and the ground measured coordinatesof n check points, that is 2iin181。 ground control points (GCPs)。Geospatial Information Science 11(4): 235242 Volume 11, Issue 4 DOI Article ID: 10095020(2020)0423508 Document code: A On Stereo Model Reconstitution in Aerial Photogrammetry YUAN Xiuxiao Abstract This paper describes the operational issues and basic technical requirements of modern aerial photogrammetry. The accuracy of photogrammetric point determination and the yparallax at corresponding model points is analyzed when stereo models are reconstituted by using the exterior orientation elements of aerial images. Real aerial photographs, at image scales from 1:2 500 to 1:6 0000, with DGPS/IMU data taken from various topographies in China were processed by our POSsupported bundle block adjustment program WuCAPS. The empirical results verified that the accuracy of the exterior orientation elements from bundle block adjustment meets the requirements of the specifications of topographic mapping. However, the accuracy of the exterior orientation elements determined by POS fails to meet the requirements of the specifications of topographic mapping. Keywords aerial triangulation (AT)。 stereo model reconstitution。 m according to the results of relative ?orientation modual with the function of gross error elimination by WuCAPS. After that, we use Applanix POS/AV system’s postprocess software POSPac[10] to do test field calibration and the integrated process of DGPS and IMU data, then by applying coordinate system transformation and system error rectification, six exterior orientation elements of each image, which were provided by the POS system, can be obtained.Table 1 Parameters of images in experimental projects test 1 test 2 test 3 test 4 Time Nov. 2020 Jan. 2020 Sept. 2020 Oct. 2020 Airplane Yun12 Yun12 Yun8 AviationII Camera Leica RC30 Leica RC30 Leica RC30 Leica RC30 Flight control system Track Air Track Air CCNS 4 CCNS 4 POS system POS AV 510 POS AV 510 POS AV 510 POS AV 510 GPS receives Astech Trimble 5 700 Trimble 5 700 Trimble 5 700 Negatives Kodak 2 444 Kodak 2 044 Kodak 2 402 Kodak 2 402 Principle distance /mm Frame /cmcm 2323 2323 2323 2323 Photographic scale 1:2 500 1:3 000 1:32 000 1:60 000 Forward overlap /％ 61 63 64 64 Side overlap /％ 32 33 33 30 Strip number 9 10 9 4 Control strips 2 2 2 0 Photos 255 377 244 48 GCPs 73 160 34 29 Densification points 3 631 5 442 2 951 712 Area /kmkm 45 58 4752 4057 Maximum terrain undulation /m (flat ground) (mountain) (high mountain) (lowland) GPS refresh rate /s 2 1 1 GPS initialize time /min 10 10 5 5 GPS static /min 5 5 5 5 GPS lever arm /m , , , , IMU lever arm /m , , , , , , Performance of exterior orientation elements In order to analyze the performance of exterior orientation elements obtained by different methods, standard AT with dense GCPs on the border and GPSsupported AT with four full GCPs in corners were firstly implemented, the six exterior orientation elements of each image can be obtianed, and their theoretic accuracy can be estimated. Then we assumed the results of standard AT as the “truth” and estimated the performance of exterior orientation elements provided by POS. The results are shown in Table 2. From Table 1, we see that the images of test 1, test 2 can be used for producing 4D product at the scale of 1:500~1:2 000, and images of test 4 for that at the scale of 1:5 000~1:10 000. In the principle of Topographic Maps Specifications for Aerophotogrammetric Office Operation[1113], test 1, test 2, test 3, and test 4 belong to flat land, mountain land, high mountain land, and lowland, respectively. From the results in YUAN Xiuxiao/On Stereo Model Reconstitution in Aerial … 239Table 2, some conclusions can be summed up as fol lows. Table 2 Accuracy of exterior orientation elements determined by different methods GCPs Check Pts RMS of check pts’ residual/m Theoretical accuracy of EO Images method σ0 /181。181。 GPSsupported AT is the easyto operate and low cost method and corresponding standards have been drafted for it。 Mapping Technology INC, Dalian Urban Surveying Design Institute, Siwei Aviation Remote Sensing Co. Ltd., Xi’an National surveying