The Research on the Problem of Supplementing Points for Land Mean Gravity Surveying in China

In the first section,this paper studies the formula for arranging gravity points.It is the relational expression between mean square error of mean spatial(Bouguer) gravity abnormal and gravity point number which can be used to calculate the gravity point number which should be guaranteed within the grid.In the second section,1) this paper offers the methods and steps of calculating the coefficients of representation error referring to the definition of representation error and relevant formula due to its important role in arranging points design of gravity surveying;2) using possessed gravitational and topographical data,the authors calculates the coefficients of representation error in the regions that have different topographical classifications;3) the paper lists the statistical results of the coefficients of representation error of spatial (Bouguer) gravity abnormal within area covering different topographical classifications;4) the authors checks the coefficients of representation error of our country's current specification,and analyzes the statistical data.The result shows that these coefficients are reliable and should be used continually.In the third section,1) since the Mean Square Error of mean topographical heights plays an important role,this paper studies and offers its estimating methods and steps;2) this paper calculates the Mean Square Error of mean topographical height within area gained from grid-point heights all over the country,and lists relevant data according to different topographical classifications,and the result shows that the calculated Mean Square Error can not conform to the standardless than ±10 m in mountains area and needs to be further refined;3) this paper analyzes the precision of the topographical data of the map database,and the result shows that Mean Square Error calculated from mean height within area gained from topographical data of future map database,will reach ±3 m in mountains area.In the last section,1) this paper studies and states the methods and steps of establishing "land gravity surveying system for arranging the gravity points";2) the paper offers the program of arranging points defined according to the research results of this paper in mean gravity surveying of our country;3) this paper offers the methods and steps of applying "land gravity surveying system for arranging the gravity points",from which we know that the system possesses practical value;4) offers the concrete methods and steps defining the gravity points which should be supplemented within each area all over the country,by which we define the gravity points number which should be supplemented within each area;(5) this paper lists the test results of "land gravity surveying system for arranging the gravity points" which shows that the system possesses abundant contents and powerful function,and can offer reliable guarantee for arranging points design and decision-making inquiry,etc.