On the Modernization of Chinese National Height Control Network

Considering the rapid development of space and information technology,Chinese national height control network,as one of the backbones of geographical spatial fundamental infrastructures,is necessary to be updated and modernized.There are two tasks for the modernization of Chinese national height control network,the first one is to update the national 1st order leveling network.To lay down a national 3rd term 1st order leveling network in the near future is according to the "Law of Surveying & Mapping of the Peoples Republic of China",which defines that "national base surveying & mapping results should be updated in certain term and base surveying & mapping results urgently needed by national economy,defense construction and social development should be updated in time." It is the guarantee to keep the Chinese vertical datum and normal height system updated and reliable.The second task is to refine the Chinese quasi-geoid to cm magnitude accuracy and 5′×5′resolution.The "GPS + geoid" technique can be used to obtain altitude with cm accuracy at any place in Chinese mainland easily and quickly.Then the modern Chinese national height control network will be a reliable and suitable height frame in the geographical spatial fundamental reference frame for China before the year of 2020.