一种基于自适应点质量的区域(似)大地水准面拟合方法

针对传统分频余差点质量模型拟合局部（似）大地水准面时系统偏差大、所需基础数据多、计算效率低等问题，利用位场等效逼近原理，对点质量模型进行改造，提出了一种位置固定、埋深自由的点质量模型，并将该模型应用到局部（似）大地水准面拟合中。利用空间距离最近点最优原则建立了解算点质量模型的迭代算法，并顾及周围点影响提出固定加权点方法和自适应法。实验结果表明，相比于传统模型，所提算法有系统偏差小、无奇异性、所需数据少以及计算效率高等优点，利用该方法进行（似）大地水准面拟合是可行的，而且自适应加权半约束点质量模型效果最好。

Quasigeoid/Geoid Determination with Adaptive Position Point Mass

Aiming at the problems during the local quasigeoid/geoid determination by traditional resi-dual point mass model, such as large system error, big amount of basic data requirement, low computational efficiency and singularity of inverse process, a new approach is presented in this paper called semi-free position point mass based on the gravity field approximation principle. Compared with the traditional model, the plan coordinates of the new one are stationary, while the depths are free. The method is established by a kind of iterative algorithm using the relationship between the nearest points. Then, the algorithm is optimized using the weights calculated by surrounding points based on their distances from the calculating point, then to obtain the best fitting result, a kind of new adaptive method to determine the optimal weighted point number is presented. Results show that the theories presented in this paper achieve higher accuracy than traditional ways, with the advantage of little system error, less modeling data, no singularity and higher accuracy. In summary, using the method to fit local quasigeoid/geoid is feasible, and the adaptive one is better.