Analysis and comparison of high-tech Xiefang's measurement accuracy of 08 elevation 1. Liaoning Urban Survey and Design Institute, Shenyang 0015, Liaoning, China; 2. Tenth Bureau of Railway Ministry, Dalian 6,21, Liaoning, China; 3. Harbin University of Science and Technology. Heilong Harbin 15, 8, the comparison of level results, and also draw useful conclusions, has a certain guiding significance for the actual production of 0; 5.

The geometric height of the earth is not what most users need, and people need to convert resources to the normal height required by most users. What accuracy can be achieved after conversion. It has been a popular course for people to explore and experiment in recent years.

Known from the theory of the elevation system. The relationship between the earth ugliness at the survey site and the normal high office can be seen from Equation 1. If the elevation abnormality at 03 can be found. It can be determined; the normal height of the extension point 1. Therefore, the key to the 8-height conversion is the elevation anomaly method, such as the numerical adjustment method, the overall adjustment method, and the integrated processing method, the moving surface method, and so on. Among them, for Bantuo users, the relatively simple, effective and practical method is the polynomial function fitting method.

High solution calculations are discussed in detail when using this method. The influence of the number of known level points and the distribution in the network on the accuracy of the fitting results.

1 The mathematical model of the function quasi-containment method The basic idea of ​​the polynomial function fitting method is to treat the quasi-geological plane as a curved surface or plane and the elevation anomaly as a function center of the plane coordinates in a small area network The common point has been measured and then the level is measured. The known height anomaly determines the shape of the geoid level in the measurement area and then finds the elevation anomalies of the remaining points. Then, these can be obtained according to Equation 1. The point is normally high, obviously. The height obtained by this fitting method is the same system as the height measured by direct leveling. It is not affected by the measurement error of the absolute coordinates of the starting point in the extension network. The mathematical model of this method selects the sub-surface to resemble the geoid. It is a plane model, and the above formulas can be combined into each common point of the following formula. It can be composed of 4. Make 2 =, and the condition 1 can be solved to find the abnormality of the remaining points in the network. The actual test network is a 3 control network in southern Liaoning. under. The whole network is composed of 25 points, the side length of the network is 351. The control area is about 250. All the points in the network have been tested by equal level. The geodetic height measured by 3 and the normal height measured by leveling are used to obtain the elevation anomaly, which is the effect of the number and distribution of common points in the study on the accuracy of the coincidence result. Our high and new technology is fragrant. 19.

A total of calculations were carried out, one of which used a plane fitting model, and the other used a subsurface fitting model.

2.1 Take the valve in the net. The side is thin, and the whole area is about 3 points 2 and 2, and points 25 and 25 are common points. The plane model is used to fit the abnormal elevation. 2.2 Take the five points accumulated on the middle side of the net about the enterprise network 2, points No. 17, 20.21 and 2325 are common points, and use the plane model to fit the elevation anomaly.

2.3 Take 3 points evenly distributed in the network; point 1519 is a common point, and the plane model is used to fit the elevation anomaly.

2.4 Take the 6 points 153142.25 of the uniform obituaries in the net as the common points to perform the subsurface coincidence.

The result of the proposed six for the scheme is that the fitting error of the scheme is large. The maximum error and the average error are 138 claws and 0.066 claws, respectively. The program has a slightly better error, and the average error is reduced to 0.0790.0381. The program and program have the best fitting accuracy. The maximum error is less than 0.06. The average error is the conclusion and recommendation 1. From the fitting experiment conducted in this paper, it can be concluded that the terrain is not uneven. If the coverage area of ​​the net is not large about 3002. So, as long as 35 level points are evenly distributed. The plane model is used for fitting calculation, and the normal high error of the solution is generally not more than 35, which can meet the tolerance requirements of ordinary geometric level measurement and can meet all kinds of large and medium. The small scale measurement has at least 1 point for elevation accuracy 3 and 2. And the distribution is ticked. Then the normal high precision solved by the surface fitting model is expected to meet the accuracy requirements of equal-level measurement.

2 The fitting accuracy of the height anomaly has a great relationship with the accuracy distribution and density of common points. The more common points. The more evenly divided the cities. The higher the viscosity just after fitting, in addition, whether it is a flat model or a curved model. If the public point is to the whole network. The castor is not good. Even if there are many points. The fitting results will also have large deviations. Deviations can sometimes reach tens of centimeters.

1 Guan Zelin. Ning Jinsheng. Beijing Surveying and Mapping Publishing House of Earth Shape and External Gravity Field. IW.

2 Research on the normal solution methods of Lan Hubiao and other networks, Wuhan University of Surveying and Mapping 3 Error theory and application. Metrology Press. 198 4 Zhang Fangren et al. Statistical distribution and inspection of measurement errors. Metrology Press. Play 91.

Paper solicitation notice Heilongjiang Provincial Institute of Surveying and Mapping The first session of the Beidai Conference and Academic Symposium is scheduled for 2,0. I hope that the majority of readers will actively participate and will carefully write the well-written papers and send them to the Institute ’s office by December 1 The paper collection work for this conference has already started. We selected excellent papers at this conference and issued outstanding paper certificates. Some articles will be published in the Northeast Survey. The specific requirements of the paper are as follows.

Main content 1 Research and discussion of surveying and mapping science and theory; Development and application of 238 technologies and 40 products; 3 High-tech and computer application of surveying and mapping; 4 Management experience of modern surveying and mapping; 5 Production practice and secondary development results; 6 Education and training Talent training; 7 surveying and mapping scientific and technological information and industrialization; 8 surveying and mapping and western development.

1Each essay should have an abstract of not more than 200 words and more than 3 keywords in front of the text of about 5000 words. And translate the article author's name and unit abstract keywords into English.

2 Manuscripts must be used, 1 typesetting, sending prints and floppy disks.

3 The size and number of the full text should be clearly structured. Parallel words in Chinese are separated by a comma; Arabic numerals and parallel words in a foreign language are separated by a comma.

4 Name of unit of measurement. Use in accordance with the national standard regulations promulgated by the State Council.

5 Attach the author's profile name, gender, age, ethnicity, graduation school, and time work unit's detailed correspondence address. The postcode and contact number 6 are at your own risk. Do not submit more articles, other matters 1 Authors should directly send to the Heilongjiang Surveying and Mapping Society. And indicate the words of the conference paper.

2 Deadline October 1, 2000.

3 Come to Qinghai, 5 cities, Nangang District, iron rank 24, Zhonglong Surveying and Mapping Society. The postcode is 1500 Ming. Quan, 4 Contact the tele-contact Wang; 1 Chapter Sun,

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