The Top 10 Articles
are available to download free from: http://maneypublishing.com/top_articles/sre/.
These are usually chosen annually by the Editor.
To ascertain other articles which have been written
by a particular author:
1. Go to http://maneypublishing.com/index.php/journals/sre/
2. Find the volume number in which the articles appeared
3. Open the volume and click on the article to open in
4. Scroll to the bottom of the page and click on 'Related content'
5. This opens up and the authors are all highlighted
6. Click on the author and this shows all the other articles written
by that author.
I am sorry this is so longwinded, but there is no other way to
do this. All this information is free.
Vol. 38, No. 298. October 2005
1. Position errors caused by GPS height of instrument blunders
T. H. Meyer and A. L. Hiscox
Height of instrument (HI) blunders in GPS measurements cause position
errors. These errors can be pure vertical, pure horizontal, or a
mixture of both. There are different error regimes depending on
whether both the base and the rover both have HI blunders, if just
the base has an HI blunder, or just the rover has an HI blunder.
The resulting errors are on the order of 30 cm for receiver separations
of 1000 km for an HI blunder of 2 m. Given the complicated nature
of the errors, we believe it would be difficult, if not impossible,
to detect such errors by visual inspection. This serves to underline
the necessity to enter GPS HIs correctly.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00001
2. Increasing reliability of the test for outliers whose
magnitude is small
Serif Hekimoglu
The power and level breakdown points measure the global reliability
of a test in robust statistics. However, they cannot give enough
information about the reliability of a test if outliers are small.
Hence, mean success rate (MSR) of a test for outliers (such as data
snooping, * ?test) was introduced. But, the MSRs of tests for outliers
are small. To increase the MSRs of tests for outliers, we propose
a new repetitive test procedure where the weights of the randomly
chosen observations are increased to the same large value such as
4. is the number of all possible outliers. The test procedure is
repeated for a given number of times and tested on a linear regression
by a simulation. One hundred generated samples with random errors
distributed normally were chosen. Random and influential outliers
are considered in the tail regions and in the whole region of a
sample. These outliers are randomly generated 100 times for each
simulated sample. Repeating the new test procedure only 20 times,
the MSR of data snooping and also the MSR of *?test are increased
for one outlier lying between 3? and 6? at a rate of 10% and 20%
respectively.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00002
3. Using GPS near the forest and quality control
A. Pirti
This paper attempts to provide some insights into the fading properties
of GPS signals. When a GPS signal reaches the antenna, it suffers
from masking and blocking effects from surrounding objects. With
respect to these effects, GPS signals can be divided into clear
signals, shadowed signals, and blocked signals.
In this article we shall examine the performance and use of GPS
based data acquisition systems near forest. As a general rule, a
clear view of the sky is preferred when using GPS for determining
location. This means that using GPS near forest is one of the most
demanding uses of technology and one that requires particular attention
when evaluating GPS receivers that will be used in such an environment.
The signal transmitted by GPS satellites are extremely low power,
and the GPS signal is about 100 times weaker than the general background
radiation at that frequency. The signal passing through your body
right now from a local television or radio station is almost certainly
several thousand times stronger than a GPS signal. GPS receivers
use sophisticated signal processing techniques to lock onto and
track the GPS satellites. However, the relatively low power of these
signals can indeed pose problems when the signal is further degraded
by a forest canopy.
Humidity of the leaves and the forest is the critical factor for
GPS performance near the forest area. Water laden leaves of tree
attenuate more signal than those that are dry. GPS signals will
be present with weak signal strengths and positions that are computed
from weak signals tend to be less accurate.
This paper evaluates GPS positional accuracy, precision and performance
near forest areas. As a result of this attenuation, positions are
computed from weak signals and tend to be less accurate.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00003
4. Robusttype biased estimation in GaussMarkov model
Gui Qingming Li Guozhong and Ou Jikuen
The parameter estimation problem in GaussMarkov model is considered
when multicollinearity and outliers exist simultaneously. A class
of new estimators, robusttype generalized shrunken estimators,
is proposed by grafting robust estimation technique into philosophy
generalized shrunken estimation. Many useful and important estimators
such as robusttype ordinary ridge estimator, robusttype principal
components estimator and so on are obtained by appropriate choices
of the shrinking parameter matrix. An algorithm for computing the
robusttype generalized shrunken estimate is established. A numerical
example is provided to illustrate that these new estimators can
not only effectively overcome difficulty caused by multicollinearity
but also resist the influence of outliers.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00004
5. Independent control of GPS networks above long tunnels by astronomically
determined azimuths or bearing angles
N Solaric, Z Versic and D Spoljaric
At the Faculty of Geodesy, University of Zagreb, the automatic
astronomical method of determining the azimuth by observing stars
and the Sun has been developed within the frame of the scientific
work. The classical astronomical method of azimuth determination
is rather uneconomical because of extensive field measurements and
longlasting processing. The automation of measuring procedures
and processing has enabled the application of the astronomical method
in everyday surveying practice, and also in determining the tunnel
cut direction, in the independent control of microtrilateration
and GPS networks above tunnels. The importance of such an independent
control of geodetic networks above tunnels lies in the fact:
1. That we control the relative positional relationships of the
points at the entrance, and the exit of a tunnel, respectively,
2. That we control whether the exact value the deflection of the
vertical have been taken into
account. Namely, the deflection of the vertical at the points for
traverse orientation used for
entering the tunnel can be remarkable which can largely influence
the traversing orientation,
especially if the orientation sighting lines are steep.
Applying the astronomical determination of azimuth as an independent
control of trilateration or GPS networks over long tunnels, the
surveyors can expect with more confidence that the tunnel be cut
without any problems.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00005
6. Evaluation of National Land Administration System in Switzerland.
Case study based on a management model
D. Steudler and I P Williamson
Currently there are no internationally accepted methodologies
to evaluate and compare the performance of land administration systems.
To engage in this discussion, the authors published a previous article
proposing an evaluation framework, which – based on a management
model – links the operational aspects of land administration
with land policy. In this new article, the framework is being applied
to a case study evaluating the national land administration system
of Switzerland. The case study puts the earlier developed framework
to the test and at the same time gives an insight into the specific
national system.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00006
7. Effects of observation plan and precision on the duration of
outliers detection and fuzzy logic: a real network application
H. Konak, A. Dilaver and E. Öztürk
During the total evaluation of measurements, it is aimed to identify
the outliers, which distorts the certain values considering all
measurement. In this manner, the determination of the best method
to form the outlier sets is also considered another problem. Due
to its structure Fuzzy Logic approach keeps the observation plan
and precision unchanged during the process of outlier identification.
The approach mentioned is suggested as a usable method due to its
properties. In this paper, a real geodetic network is tested using
three different network models. The locations of outliers are searched
by fuzzy logic approach, and the success of the method is compared
with those of other alternative methods.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000298/art00007
Vol. 38, No. 297. July 2005
1. Diagnosis of outlier of type Multipath in GPS Pseudorange
Observations
J. L. Awange
The nonlinear GaussJacobi algorithm which exploits the capability
of algebraic tools of Groebner basis and Multipolynomial resultants
to solve in a closed form polynomial system of GPS pseudorange
equations is here proposed as a possible tool for detecting the
satellite, whose pseudorange has been contaminated by the error
of type Multipath. By injecting gross errors of 200m and 500m on
the pseudorange observations from two satellites, it is demonstrated
how the GaussJacobi combinatorial algorithm detects the falsified
satellite and in addition identifies poor geometrical combination
of the satellites, which is normally identified via PDOP. Indeed,
the GaussJacobi combinatorial algorithm proposed is a straightforward
tool, which adopts a deterministic approach that deviates from the
statistical stochastic approaches to outlier detection. Outliers
are simply detected based on the combinatorial approach first proposed
by C. F. Gauss in 1828 and published posthumously but which C. G.
I. Jacobi later independently published in 1841. The computing engine
for the GaussJacobi combinatorial algorithm, Groebner basis or
Multipolynomial resultant algorithms for computing pseudoranges
have already been prepared by J. L. Awange and E. W. Grafarend and
can be accessed in the GPS toolbox via http://www.ngs.noaa.gov/gpstoolbox/awange.htm.
The proposed algebraic approach proves to be a powerful tool in
detecting outliers and could be applied not only to GPS pseudorange
problem but to any problem that permits the conversion of its system
of equations into algebraic (polynomial form). This is demonstrated
using the planar ranging problem.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00002
2. Precision and Results Reliability Analysis of different instruments
for investigating vertical microdisplacement of structures
D.B.Kovacic and D.Z.Kapovic
This paper presents an analysis of the precision and results reliability
of different instruments when researching the vertical displacements
of objects in a space. In Slovenia the researching at objects by
pressure testing is obligatory for all structures longer than 15
metres (JUS U.M1.046). We chose both geodetic and nongeodetic methods.
There are many methods for researching displacements, so we limited
it to the instruments available to us. The Faculty of Civil Engineering,
University of Maribor, Slovenia, uses the total station, level,
and the inductive transducer and laser level. The displacement measurements
were made on a reinforced concrete plate, type PVP5. We calculated
the foreseen displacements by the analytic as well numeric method
for the plate. We used the National regulations (Euro code 2) for
analytic calculation and for the numeric part we used the Ocean
program. We calculated the standard deviation and the optimal accuracy
for each instrument, we also checked the significance of the results
by an analysis of the variances with one variable factor and by
using the “Baarda’s data snooping” method we also
did a check for the presence of rough mistakes that can occur in
the measurement results.
In this paper we describe all the instruments for following the
displacements and the working principles of the instruments with
which the research was carried out, and the measurement errors.
The precision analysis was made on the basis of a comparison between
the results of the foreseen displacements and the gained results
of the measurements. The results of this research are collated in
the conclusion and give us the answers to our goals.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00003
3. A Computational approach to the Robinson Projection
C. Ipbuker
The Robinson projection is the most preferred world map projection
in the atlas cartography. There are no analytical formulas except
Robinson’s lookup table for this projection. This deficiency
has led a number of requests for the plotting formulas and cartographers
have studied to derive analytical equations using different algorithms.
In these works, different interpolation algorithms are applied to
Robinson’s table values and solutions are presented including
some critics about the deformations on this projection. In this
study, a summary of these computation algorithms is collected. The
multiquadric interpolation method is suggested and applied to the
Robinson’s tabular coordinates. A series of numerical evaluations
are presented then for the controversies and for comparison between
these computation algorithms.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00004
4. PDOP values for simulated GPS/Galileo Positioning
Peter Cederholm
The paper illustrates satellite coverage and PDOP values for a
simulated combined GPS/Galileo system. The designed GPS satellite
constellation and the planned Galileo satellite constellation are
presented. The combined system is simulated and the number of visible
satellites and PDOP values are estimated at 4140 points around the
earth. The simulation that is carried out with a 15 degrees cutoff
angle is repeated every 10 minutes for 72 hours. The simulation
shows that mean PDOP values are improved significantly when using
a combined system compared to using only GPS.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00005
5. Modelling landslide surfaces by kinematic and dynamic
surface models: a case study in North Eastern Turkey
M. Yalçinkaya , T. Bayrak and A. Yalçin
Landslides occurring over time can be visually monitored by surface
models. In addition, point movements that have not been measured
can be determined with these models using extrapolation. There are
several surface models including kinematic and dynamic. In the kinematic
surface model, the surface is determined as dependent on time. In
the dynamic surface model, the surface is determined regarding cause
of movement in addition to time. Landslides are not simple twodimensional
features but have a threedimensional form and a complicated temporal
context. They are dynamic systems that are complex in time and space.
Therefore, in this study, a dynamic surface model regarding the
cause of landslides was developed to monitor landslides and determine
movement surface.
Kutlugün Village, a landslideprone area in Maçka County
in the Province of Trabzon in Eastern Black Sea Region of Turkey,
was selected for the study. Geological and geophysical investigations
were made and it was determined that the change in the groundwater
level was the most important cause of landslides. Groundwater level
changes were taken into account in the formation of the dynamic
surface model. Groundwater levels were measured at three bore holes
and at two geophysical points. In addition, a geodetic control network
covering the whole region and its surroundings was established.
The point coordinates were determined by GPS. Using this data, a
dynamic surface model was developed. The model includes computations
of surface coefficients and groundwater effect coefficients. Through
this model, dynamic surfaces were determined for the measurement
periods. For the same measurements periods, kinematic surfaces were
also determined. The results derived from both models were compared.
It can be seen that groundwater changes affected surface changes.
These surface changes which occurred over time were determined more
realistic by the dynamic surface model
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00006
6. Determination of the optimal diameter for spherical
targets used in 3D laser scanning
Yuriy Reshetyuk, Milan Horemuž and Lars E. Sjöberg
An efficient use of 3D laser scanning requires the development
of standardized calibration procedures available to the users. This
is part of the research recently started at the Royal Institute
of Technology (KTH) in Stockholm and the establishment of a calibration
field is planned, which may be realized by means of spherical targets.
An approach for the rigorous theoretical determination of the optimal
diameter for those targets is presented. It is based on the leastsquares
adjustment according to the mixed model when observations are combined
with the unknown parameters. The weight function was chosen based
on the Lambertian standard reflectance model. The computations were
performed for the scanners Leica HDS 3000 and Imager 5003 (Zoller+Fröhlich)
for two cases – with fixed and “free” (to be estimated
in the adjustment) target diameter. The value of 14 cm has been
obtained for the optimal diameter, which is independent on the range
to the scanner.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00007
7. The influence of the sea on driving the Channel Tunnel
A Johnston
Due to a small lack of symmetry between the left and right hand
wall bracket survey stations in relation to the tunnel centreline
and a difference between left and right sides in the array of pipes
and cables on the walls, the airflow differed between the sides
of the tunnel. This, and the annual sea temperature variation, produced
a small but detectable effect on the tunnel setting out survey.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000297/art00008
Vol. 38, No. 296. April 2005
1. Augmenting GPS by groundbased pseudolite signals
for airborne surveying applications
Hung Kyu Lee, Jinling Wang, Chris Rizos and Toshiaki Tsujii
This paper discusses some issues associated with the implementation
of groundbased pseudolite augmentation for GPS airborne surveying
applications. For instance, not only should two antenna offsets
(one on the top of, and the other underneath, the platform) be corrected
for, but the number, the location, and the geometric distribution
of the pseudolites on the ground has to be carefully considered.
Initial analyses have shown that the accuracy requirement for the
attitude parameters is dependent on the magnitude of the offsets
between the two antennas. In addition, a series of simulations has
demonstrated that pseudolite augmentation can significantly improve
the quality of the positioning solutions, especially the vertical
component accuracy (due to the negative elevation of the pseudolites).
The optimal number and locations of the pseudolites are dependent
on the satellite geometry. Based on selected optimization criteria,
a comprehensive search would typically be needed for a specific
application. A geometric analysis and measurement testing procedure
for this purpose will be described in this paper.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00001
2. On the quality of distance measurements in athletics
throwing events
M. Tsakiri, M. P. Stewart, A. Snow and J. Karabelas
Distance measurement in athletic throwing events is fundamentally
a surveying problem which should follow the appropriate quality
control procedures. This paper discusses the measurement procedure
adopted by the IAAF (International Association of Athletics Federations)
for throwing events, with particular emphasis on the javelin event.
Published National Survey Standards are applied to form models of
the errors associated with the IAAF procedure. The effect of these
random error models on measured throwing distances is discussed
statistically with probabilities of ‘miscarriages of justice’
(one athlete throwing less far than another but being awarded a
longer distance by the officials) being presented. Finally some
comments and recommendations regarding the IAAF measurement specifications
are made.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00002
3. A new approach to the iterative calculation of geodetic
latitude and its application
J. Pollard
A new approach to the determination of the geodetic latitude of
a point from the size of a geocentric ellipse which passes through
the point is introduced. It produces a solution from the geocentre
out and is shown to improve the efficiency of existing iterative
methods.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00003
4. Applying the theory of planned behaviour to cadastral
Michael Barry
Planners of cadastral systems need to predict how formalising
land rights will affect communities that are supposed to benefit
from them. In particular, it is important to evaluate if the intended
beneficiaries are likely to use the cadastral system. If they do
not, addressing the consequences may be costly in time, money and
resources. The theory of planned behaviour was adapted, developed
and tested as a framework for analysing and predicting land registration
and legal boundary usage in a number of urban settlements in Cape
Town, South Africa. A study of the upgrading of the Marconi Beam
informal settlement to a formal housing project confirmed existing
theory – that is, when dealing with informal settlements,
predictive models such as the theory of planned behaviour should
be applied with caution. The complex social and political dynamics
of informal settlements suggest that in volatile situations investigations
should include comparative case studies of actual usage behaviour.
Otherwise, the results are not likely to serve as an accurate predictor
of usage of the cadastral system. However, the theory of planned
behaviour does provide a structure for designing a study and it
provides the classes of data that should be collected and analysed.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00004
5. Pedal hypersurfaces and DOP factors in GPS
A. Antonopoulos and D. Antonopoulou
The hypervolume “enclosed” by the standard error pedal
hypersurface is a proper measure of total uncertainty in multidimensional
determination (usually) of positioning. This quantity especially
of use in GPS positioning is upper bounded by a handy function
of the associated DOP factor and minimized, for a given DOP factor,
if and only if the precision of positioning is independent of “direction”.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00005
6. Monitoring vertical movements in Mount Carmel by means
of GPS and precise levelling
G. EvenTzur and E. Agmon
Mount Carmel fault is one of the major geological structures in
northern Israel, characterized by intense, continuous, and potentially
hazardous seismic activity.
A small monitoring network, spanning an area of 40 by 30 km. and
consisting of 17 points, was constructed. Four sets of GPS measurements
were taken between 1990 and 1999 as well as two campaigns of precise
levelling. TwoStep analysis of the GPS measurements was carried
out to quantify recent vertical tectonic deformations.
Strict analysis of the GPS and the levelling data shows significant
vertical movements in the area. Two independent methods are pointing
to the same vertical behaviour at the monitored region, indicating
that the Carmel range uplifts at a rate of 5 mm per year relative
to its surroundings.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00006
7. Cumulative estimation in semiparametric models
(NONPARAMETRIC ESTIMATOR BASE FOR A GENERAL WEIGHT FUNCTION)
Hongchang Hu Haiyan Sun
This paper considers a particular semiparametric model Firstly,
the cumulative estimation method of linear model is applied to the
semiparametric model, moreover, a general weight function is chosen
as the nonparametric estimator. Both estimators are obtained. Secondly,
some statistical properties of estimators are discussed. Finally,
an example is imitated, which shows validity of the cumulative method.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00007
8. Improving an algorithm for total electron content estimation:
experiments from Esfahan
Vahab Nafisi, Mehran Sattari, and Mehdi Momeni Shahraki
It is possible to use single frequency GPS receivers to estimate
the Total Electron Content (TEC). In this research, we improved
an algorithm presented by Giffard [2], that is
based on a least squares solution. We investigated the effect of
the use of different weights (elevation of satellites, signal to
noise ratio, combination of elevation and signal to noise ratio)
and different block sizes on TEC estimates. We found that these
parameters had a significant impact on TEC estimates based on this
algorithm. Our research is based on observations at the GPS site
of the Esfahan University made with single frequency 12channel
Leica System 500 receivers.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000296/art00008
Vol. 38, No. 295. January 2005
1. Multipath mitigation by Wavelet analysis for GPS base
station applications
Chalermchon Satirapod and Chris Rizos
It is well known that multipath disturbance is one of the major
error sources impacting on high precision GPS positioning. The multipath
disturbance is largely dependent on the receiver’s environment
since satellite signals can arrive at the receiver via multiple
paths, due to reflections from nearby objects such as trees, buildings,
vehicles, etc. Although the multipath effect can be reduced by choosing
sites without multipath reflectors or by using chokering antennas
to mitigate the reflected signal, it is difficult to eliminate all
multipath effects from GPS observations. Since the geometry between
the GPS satellites and a specific receiverreflector location repeats
every sidereal day, multipath tends to exhibit the same pattern
between consecutive days. This repetition can then be useful for
verifying the presence of multipath through the analysis of observations
made at a static receiver on different days. In this study, the
authors apply a wavelet decomposition technique to extract multipath
from GPS observations. The extracted multipath signature is then
applied directly to the GPS observations to correct for the multipath
effects. The results show that the proposed method can be used to
significantly mitigate the multipath effects at a permanent GPS
station.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00001
2. Engineering survey work in the construction of floating
docks
Petar Cerovac
The paper presents the engineeringsurveying work carried out during
the construction of floating docks in several parts on the berth
and joining these parts on the water. These investigations were
performed with regard to the construction of a steel threepontoon
floating dock with the possibility of self docking; the obtained
results have been applied during its construction.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00002
3. A fuzzy logic approach to the Ginzburg IV projection
O. Akyilmaz, T. Erden and C. Ipbuker
Ginzburg IV projection, which is also known as the CNIIGAiK 19391949
projection, is a modified polyconic projection that was preferred
in the old USSR for mapping the whole world. There exist no mathematical
equations which define the projection. In the Russian literature,
the plane coordinates belonging to a given geographical latitude
and longitude are given on tables in 10 degree interval. In this
study, the fuzzy logic method is suggested for modelling geographical
grids which are defined only with tabular coordinates, such as in
the Ginzburg IV projection.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00003
4. Application of total station and laser correlation survey
and depth measurement in an underground mine shaft
P P Bahuguna
The present paper describes a casehistory of an application of
modern surveying instruments in the correlation survey and depth
measurement in a 400 m deep vertical underground mine shaft sunk
from a depth of about 500 m to a depth of 900 m below the ground
level. The technique presently used differs from other earlier techniques
in that the depth is measured directly at various horizons in the
shaft, from bottom to top, by using a total station.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00004
5. Decimetre level mapping using differential phase measurements
of GPS handheld receivers
Ahmed ElMowafy
An economic positioning system is presented in this study for decimetre
level accuracy mapping with emphasis on producing base maps for
GIS applications. The system downloads carrierphase data of GPS
handheld receivers online, simultaneously registers the point code
and description, and processes the data in a differential postmission
mode. The architecture of the system is presented. Characteristics
of the proposed system are discussed. Main issues in system utilization
are investigated, including: treatment of system errors, phase measurements
ambiguity resolution, the impact of receiver dynamics on system
performance, and the required occupation time per point. Some guidelines
for system operation are proposed. Several tests in the static and
kinematic modes were carried out to test the performance of the
proposed system. The system gave very promising results. Test results
show that for a probability of 95%, an accuracy of less than 16
cm can be achieved after correctly resolving the ambiguities. With
a cost that is a fraction of that of the currently used geodeticgrade
GPS receivers, the system represents a cheap alternative for a wide
range of GIS applications.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00005
6. Polynomial versus similarity transformations between
GPS and Turkish reference systems
M Soycan
Efforts to utilize GPS have increased and come a long way in recent
years. GPS (Global Positioning System) is the most modern and reliable
technique for surveying geodetic control networks. By using relative
static GPS observation, it is possible routinely to obtain subcentimetre
positional accuracy for points in geodetic control networks. GPS
uses WGS84 (World Geodetic System 1984) as its reference frame.
Point position on the earth is obtained by GPS observation in this
frame. However, in geodetic and engineering applications, different
coordinate systems are used as local or national systems. Combination
of GPS networks with the national coordinate system requires determination
of the transformation parameters between WGS84 (or ITRF) and the
relevant national coordinate system. Several models can be used
for transformation. The main purpose of this research is examination
of 2 and 3D polynomial transformation models instead of 2 and 3D
similarity transformations for distorted networks. However, the
study also aims to determine reliable transformation parameters
between ITRF94 and Turkish National Reference frame ED50 for Istanbul.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00006
7. Development of Singapore integrated multiple reference station
network (SIMRSN) for precise fast static positioning
G. Hu, V. H. S. Khoo, P. C. Goh and C. L. Law
Fast and high precision GPS relative positioning is now increasingly
used for many surveying applications on land and at sea. However,
this technique requires the distance between the reference receiver
and the user receiver to be within about 10km for high precision
surveying work. Most users need to set up their own reference stations
for DGPS measurements. This constraint will be removed by using
a multiple reference station network. In order to use fast static
centimetrelevel positioning over larger distances, the Singapore
Integrated Multiple Reference Station Network (SIMRSN) has been
established in Singapore. The objective of this paper is to illustrate
accuracy improvements in a fast static positioning mode using the
corrected observations derived from within the SIMRSN network. After
obtaining Test results are presented to demonstrate the improvement
brought by the multiple reference station network approach.
Further information:
http://www.ingentaconnect.com/content/maney/sre/2005/00000038/00000295/art00007
