The Impact of Different Mapping Function Models and Meteorological Parameter Calculation Methods on the Calculation Results of Single-Frequency Precise Point Positioning with Increased Tropospheric Gradient

Table 1

The properties of different troposphere mapping functions.

Mapping function	Reference	Input parameters	Output parameters
B&E	Black and Eisner [15]
GMF	Boehm et al. [6]	and ERA-40 data at grid
Hopfield	Hopfield [16]
NMF	Niell [11]
VMF1_site	Boehm et al. [6]	,VMF1 site file
VMF1_grid	Niell [11] and Kouba [17]	,VMF1 gridded file, orography_ell file
VMF3_site	Landskron and Bohm [18]	, VMF3 site file
VMF3_grid	Niell [11], Kouba [17], and Landskron and Boehm [18]	, VMF3 gridded file, orography_ell file

and represent the station latitude and longitude, represents the altitude of station, represents the day of year, is the elevation angle, is the surface pressure, is the surface temperature, denotes modified Julian data, ERA-40 is a European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis of the global atmosphere and surface conditions over the period 1957–2002, and are coefficients for determining Vienna Mapping Functions (VMF1), and are hydrostatic and wet mapping functions, respectively, and and are zenith hydrostatic delay and zenith wet delay, respectively.