Abstract:In this paper, the precision of gravity field model under double precision and quadruple precision mode is compared and analyzed based on dynamics method, including the calculation of associated Legendre function, numerical integrator and gravity field inversion results. In terms of Legendre function calculation, part of the angle can be calculated in the double accuracy mode to the 1 900 order and overflow problems occur beyond this order. However, in quadruple precision mode any angle satisfies the accuracy requirement and the result is 8 orders of magnitude higher relative to the double precision mode. The quadruple precision model of numerical integrator Adams predictive correction method is 4 orders of magnitude higher than the double precision model. In terms of gravity field inversion, the inversion results of dynamic method are consistent in double and quadruple precision mode, and the accumulated geoid error calculating to order 60 is statistically 1.29×10-5 m, mainly because the linearized error of the dynamics method dominates the calculation error. The nonlinear dynamics method is 7 orders of magnitude higher than the double precision model in the quadruple precision model, and its accumulated geoid errors are respectively 8.92×10-15 m and 8.16×10-8 m.
ZHU Yongchao,WAN Xiaoyun,ZHOU Baoxing. Accuracy Analysis of the Double Precision and Quadruple Precision Gravity Field Solution[J]. jgg, 2020, 40(1): 94-97.