Positioning, 2013, 4, 8-10
http://dx.doi.org/10.4236/pos.2013.41002 Published Online February 2013 (http://www.scirp.org/journal/pos)
Effect of Height and Geographic Latitude of Location of
GPS Station on Ratio of Total Amount of Water Vapors
on Wet Delay of GPS Signals
Garib Shamil Mamedov
1
, Ramiz Ahmed Eminov
2
, Elchin Ibad Maharramov
3
,
Hikmat Hamid Asadov
4
1
State Committee on Land and Mapping, Baku, Azerbaijan;
2
Azerbaijan State Oil Academy, Baku, Azerbaijan;
3
State Aero Geodesy
Enterprise of the State Committee on Land and Mapping, Baku, Azerbaijan;
4
Research Institute of Aerospace Informatics, Baku,
Azerbaijan.
Email: hasadzade2001@yahoo.com
Received November 22
nd
, 2012; revised December 23
rd
, 2012; accepted December 31
st
, 2012
ABSTRACT
The averaged integrated parameter representing the mean value of ratio of total water vapors on wet delay
PWV
ZWD
at
the chosen distance of latitude
max
0 is suggested. The function of interrelation of such parameters as height of lo-
cation site and latitude is suggested. It is shown, that the optimal function H f does exist which bring the aver-
aged integrated parameter to its minimal value.
Keywords: Wet Delay; GPS; Water Vapors; Measurements; Optimization
1. Introduction
It is well known, that in meteorology all information
concerning the processes taken place at the Earth’s sur-
face is obtained using ground measuring instruments,
installed in the observation stations and satellites. It
should be taken into account, that density of location of
observation stations is not so high and in order to calcu-
late the required meteorological parameter for any geo-
graphical point located among the observation stations
the mathematical methods of interpretation should be
applied. This question is studied in the work [1], where
the necessity of integrated accounting of such factors as
orography, presence of water vapors, and latitude effects
arising in determining the effective values of distances
upon interpolation of meteorological fields is discussed.
The calculated effective values of distances can be used
by purposes of interpolation of such meteorological pa-
rameters as mean monthly values of daily sums of dura-
tion of solar irradiation, daily extremal values of air
temperature, atmospheric pressure of water vapors etc.
2. Brief Review of Background of Research
Task
In the work [1], it was shown that the taking into account
of latitude effects on estimate of interpolated values of
distances increases the accuracy of interpolation. In this
case the orography effects can be corrected by the way of
weighted accounting of difference of location heights of
studied objects. In the work [1] the following formulae is
suggested to determine in effective value of distance
eff
between point P and points where the measure-
ments
d
i
X are carried out
2 2 2 2 2
eff NS qeo oro
d f d f h , (1)
where
sin sin
1 0.3 1
2
p x
NS p x
f
, (2)
where
qeo
—the geographic distance; d
p
and
x
—
latitudes of points P and X; h —difference of heights
of points P and X; 500
oro
f .
As it is seen from Formulas (1) and (2), upon carrying
out the interpolation calculations for such important pa-
rameters GPS systems as mean temperature and total
amount of precipitable water vapor, the geographical
latitude and height of location of relevant sites should be
taken into account. The similar question is also discussed
in detail in the work [2].
As it is noted in the work [2], measurements of total
amount of water vapors in atmosphere using ground GPS
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