基于改进射线描迹法的对流层斜延迟估计

Estimation of Tropospheric Slant Delay Based on Improved Ray Tracing Method

该文针对传统对流层延迟模型和射线描迹法在估计对流层延迟方面的局限性,如效率低、成本高、精度受地表参数和探空数据限制等不足,提出一种基于改进射线描迹法的对流层斜延迟估计方法。该方法结合中纬度大气模式气象参数公式和UNB3m气象参数模型,改进了射线描迹法中折射率剖面的计算,克服了气象数据对射线描迹法的限制。选取亚洲地区10个站点2012年的气象数据,分别采用改进射线描迹法和传统对流层延迟模型估计各个站天顶方向至4?高度角区间15个方向的对流层斜延迟,并与基于探空数据获取的对流层斜延迟真值进行比较,计算结果表明该方法的估计精度优于传统对流层延迟模型,为非气象数据情况下对流层斜延迟实时估计提供了新的思路。

The tradition tropospheric delay models and the method of ray-tracing have some limits like inefficiency, high cost and the the restrictions of radiosonde data and surface parameters. An improved method based on ray tracing is proposed. In this method, meteorological parameter formulas in the middle latitude model and meteorological parameter models in UNB3m model are combined to modify the arithmetic of refractive index, which gets rid of the restrictions of radiosonde data. Meteorological data from 10 Asia stations in 2012 are analyzed based on ray tracing technology and tradition models like Hopfield and Saastamoinen. Slant delays for 15 directions from the zenith to 4° elevations, are computed. The results are compared with ray-tracing tropospheric slant delays from nearby radiosonde measurements, which demonstrates that the accuracy of improved ray tracing method is superior to tradition models, and the proposed method provides a new real time way for estimating tropospheric slant delay in the case of lack of meteorological data.