Regional Centimeter Rank Accurate Geoidal Surface And Its Apply Study

This article mainly discussed some problems about the conversion from geodetic height to normal height, the limitation of calculating height with GPS analog integration method, and how to decide the height problem with the help of gravity, existing surveying and mapping material, and accurate geodetic level through precising GPS control surveying. As every knows, we can simultaneously get the three-dimensions coordinate of a control point with GPS technique, that is to say, get the plane position and geodetic height of the control point. As geodetic height is inconsistent with the height system adopted by our country (normal height system), this important resource surveyed by GPS technique is often wasted. If we can use physical method of geodesy to accurately get the same point's difference between geodetic height and normal height, i.e, the geoidal difference, then, geodetic height obtained from GPS can be changed into normal height, thus, the important resource from GPS can be fully used. By setting up garden GPS framework, basic GPS control network and completing the refining work of the centimeter rank geoid of the garden, we can actually realized that while obtaining high accurate horizontal position of a point, we can also get its level height. Thus, GPS method can replace trigonometric(traverse) and low-order-level or trigonometric height survey, make the most of the strong points of high accuracy, low cost, quickness and flexibility of GPS, to reduce the amount of field work and cut down production cost.