Area quasi-geoid refining method based on earth gravity model (EGM2008)

Abstract

The invention relates to an area quasi-geoid refining method based on an earth gravity model (EGM2008). The method comprises the following steps of: 1) determining an area range and distributing control points; 2) performing field measurement (data acquisition); 3) on the basis of the EGM2008, acquiring a gravity height anomaly of each control point; 4) fitting a quadratic polynomial; 5) measuring adjustment; 6) performing analog computation on a neural network; and 7) refining a model. By adoption of the method, the accuracy of an area height anomaly computation result is high, and the application range of a measurement result of a global positioning system (GPS) height is expanded. Compared with the conventional quadratic polynomial fitting method, the method provided by the invention has the advantages that by a great amount of engineering project application result analysis, the accuracy of a height anomaly computation result is improved by 20 to 50 percent; after the accuracy is improved, the GPS height can replace low-level leveling, so the workload of the conventional low-level leveling which is high in cost, high in difficulty and long in period is reduced to the greatest extent, and economic benefit is obvious; and the method is applicable to the technical field of geodesy.

Description

Technical field [0001] The present invention belongs to the technical field of "geodesis" in the subject of "Surveying and Mapping Science and Technology", and specifically relates to an EGM2008-based refinement method of a regional quasi-geoid. Background technique [0002] The quasi-geoid is the elevation datum for obtaining geospatial information. If a high-precision quasi-geoid model can be established, with the help of high-precision GPS measurement technology, the normal height can be measured indirectly, which can directly serve the engineering application, thereby eliminating the need Traditional leveling with huge workload. At the same time, the establishment and refinement of local or regional geoid models is of great significance to the establishment and maintenance of the national elevation reference frame in the current GPS positioning era, and is also a geodetic infrastructure for the development of surveying and mapping in a country. [0003] In recent years, many c...

AI Technical Summary

Problems solved by technology

At present, our country basically adopts the quadratic polynomial fitting method. Although the calculation result of this method is stable, the accuracy of the calculation result is not high, which makes the application range of the GPS elevation measurement results small, and this method does not consider the gravity data. It is a geometric fitting method. face, no physical meaning

[0007] 2) The neural network BP algorithm fitting method, the accuracy of the calculation results is obviously higher than that of the quadratic polynomial fitting method, but the calculation is complicated, the calculation time is long, and the calculation results are unstable. Moreover, if the gravity data is not considered in the input parameters of the BP model, The calculation results also lack physical meaning, so this method is seldom used in engineering at present

[0008] 3) Gravity method, the calculation accuracy is high, and the calculation result can reflect the physical meaning of quasi-geoid, but the gravity data is difficult to obtain, and the calculation is complicated

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