Assessment of GNSS PPP-Based Zenith Tropospheric Delay

A New Zenith Tropospheric Delay Grid Product for Real-Time PPP Applications over China

Tropospheric delay is one of the major factors affecting the accuracy of electromagnetic distance measurements. To provide wide-area real-time high precision zenith tropospheric delay (ZTD), the temporal and spatial variations of ZTD with altitude were analyzed on the bases of the latest meteorological reanalysis product (ERA-Interim) provided by the European Center for Medium-Range Weather For...

Analysing the Zenith Tropospheric Delay Estimates in On-line Precise Point Positioning (PPP) Services and PPP Software Packages

As Global Navigation Satellite System (GNSS) signals travel through the troposphere, a tropospheric delay occurs due to a change in the refractive index of the medium. The Precise Point Positioning (PPP) technique can achieve centimeter/millimeter positioning accuracy with only one GNSS receiver. The Zenith Tropospheric Delay (ZTD) is estimated alongside with the position unknowns in PPP. Estim...

Estimation of Tropospheric Zenith Delay and Gradients

We have analyzed data from an experiment over the Madrid (Spain) area obtained from 5 GPS receivers and 3 Water Vapor Radiometers (WVR), in order to compare their retrievals of Tropospheric Slant Delays. For this purpose we have tted a simple gradient model to both types of data, using a Kalman lter to account for the temporal variability of the zenith and gradient parameters. We show that the ...

An improved global zenith tropospheric delay model

Tropospheric Range Error at the Zenith

The atmospheric range error in an electromagnetic signal arriving vertically at the earth is measured by the height integral of the refractivity N through the atmosphere. (N = 10^ (n-1) where n is the index of refraction.) N in the non-ionized atmosphere is the sum of "dry" and "wet" components, which are considered separately. Only the dry part is important at optical wavelengths,and the prese...