摘要
海拔高在工程应用中有不可代替的作用。测量海拔高的经典方法是几何水准 ,它的主要缺点是劳动强度大、效率低、花费大、实时性差。GPS海拔高测量在很大程度上克服了这些缺点 ,而且可以满足许多应用的高程需求。GPS海拔高测量代替水准测量 ,以GPS海拔高测量为主的“高程现代化”代表大地测量的一个发展方向。
The height above sea level (HASL),a general term of orthometric height,normal height and dynamic height,is extensively used in engineering project.The conventional method for determining the HASL is the geometric leveling,its primary drawbacks are labor_intensive,non_cost_effective and non_real_time in nature,whereas GPS HASL survey can overcome these drawbacks to a great extent.The GPS HASL survey is in essence the height transferring from the GPS surveyed ellipsoidal height to the height above sea level in terms of geoidal height.It has been proven feasible.This paper is devoted to the GPS HASL survey. The concept of height modernization was put forward by the U.S.National Geodetic Survey,in recognition of the situation that on one hand the line_of_sight leveling does not meet the needs of today's mobile and technology_driven society in regard to efficiency and accuracy,and on the other hand,the GPS has been capable of providing in real time accurate height needed for a wide range of applications.Its main idea is to use the GPS rather than the geodetic leveling to measure the height above sea level and to strengthen the aspect of the national spatial reference system.The height modernization involves the research and development activities seeking to improve the ellipsoidal height determination and to refine the geoid and the activities leading to improved height determination both for the static survey and for the moving navigation.The technical feasibility of GPS HASL survey depends on the accurcay of ellipsoidal height and the availability of high accuracy and high revolution geoid.The prerequisite for the ellipsoidal height determination is the existence of a GPS network of points of sufficient density,which should contain continuously operational reference stations and A and B order points.While for constructing the geoid in a large area with the centimeter level it is necessary to have banks of dense gravity points and a great quantity of GPS/leveling points well distributed throughout the territory.
出处
《武汉大学学报（信息科学版）》
EI
CSCD
北大核心
2001年第5期377-380,共4页
Geomatics and Information Science of Wuhan University
