張浩然

　　(濟寧市黃淮水利勘測設計院，山東 濟寧 272000)

　　摘 要：常見高程系統包括大地高、正高及正常高系統，由于 GPS 測量的大地高在實際測量中的應用十分有限，須采用高程擬合技術，將大地高轉換成為正常高，但轉換過程中會出現高程異常，因此采用擬合方程對已知高程進行異常處理。高程擬合方法包括多項式與多面函數擬合法，在 GPS 擬合原理基礎上，對二次多項式、三次多項式、多面函數 3 種擬合方法的高程異常及擬合差值進行分析計算，并將擬合方法應用于地形起伏差異不同的 2 個測區，對 3 種擬合方法的精度評定進行比較分析。結果表明：三次多項式擬合方法的精度要優于二次多項式和多面函數的擬合精度，說明三次多項式擬合更適用于水利測繪工程，且通過三次多項式擬合方法可減少水利測量工作，提高測量精度和工作效率。

　　關鍵詞：GPS;高程系統分析;高程異常;擬合方法;三次多項式;水利測量

　　Research on the application of GPS elevation fitting in hydrographical surveying

　　ZHANG Haoran

　　(Jining Huanghuai Water Conservancy Survey and Design Institute，Jining 272000，China)

　　Abstract：Common elevation systems include geodetic height, orthometric height, and normal height systems. Due to rare applications of GPS geodetic height in practice, elevation fitting technology must be applied to convert geodetic height to normal height, during which elevation anomalies will occur. Therefore, fitting equations are applied to deal with known elevations. The elevation fitting methods include polynomial and polyhedral function fitting methods. Based on the GPS fitting principle, the height anomalies and fitting differences of the three fitting methods, which are quadratic polynomial, cubic polynomial, and polyhedral function are analyzed and calculated. The fitting methods are applied to two survey areas with different topographic differences, where the evaluation accuracy of the three fitting methods is compared and analyzed. The results show that the accuracy of the cubic polynomial fitting method is better than that of the other two methods, which shows that the cubic polynomial fitting is more suitable for hydrographical surveying and mapping. It leads to a considerable reduction of surveying work and improves surveying accuracy and work efficiency.

　　Key words：GPS;elevation system analysis;height anomaly;fitting method;cubic polynomial;hydrographical survey