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KTIMATOLOGIO S.A.
Realization of ETRS89 in Greece by the Realization of ETRS89 in Greece by the HEPOS networkHEPOS network
53th EUREF TWG Meeting, Gävle, June 1, 2010
M. Gianniou
KTIMATOLOGIO S.A.KTIMATOLOGIO S.A. (Hellenic Cadastre)
Geodetic Department
1. HEPOS Project
2. Densification project
3. Initial and recent solution
Initial solution
OutlineOutline
53th EUREF TWG Meeting, Gävle, June 1, 2010
4. Initial solution
5. Recent solution
6. Comparison of initial and recent solution
1. HEPOS Project1. HEPOS Project
Framework of establishment
• part of the project “Information and Technology Infrastructure for a modern Cadastre”
• a CSF-III project, co-funded by the European Regional Development Fund
53th EUREF TWG Meeting, Gävle, June 1, 2010
• HEPOS was deployed in 2007, in less than 12 months
• supports other CSF-III projects, i.e. production of orthophoto maps for whole Greece
1. HEPOS Project1. HEPOS Project
98 Reference stations:
53th EUREF TWG Meeting, Gävle, June 1, 2010
98 Reference stations:
• 87 supporting network- based techniques(VRS - FKP - MAC)
• 11 for Single- base
positioning
2. Densification project2. Densification project
GLSV
GRAZ
JOSE
WTZR
113 stations
EPN
Total 14
Class A 1313
In the densi-
fication zone
3
53th EUREF TWG Meeting, Gävle, June 1, 2010
NICO
TRAB
ANKR
RAMO
MATE
NOT1
ORID
TUC2
NOA1
AUT1
fication zone
HEPOSHEPOS
Total 99(98+1)
4-char ID Full Name Country Domes No. Network
1 GLSV KIEV UKRAINE 12356M001 EPN class A, IGS
2 JOZE JOZEFOSLAW POLAND 12204M001 EPN class A, IGS
3 MATE MATERA ITALY 12734M008 EPN class A, IGS
4 NICO NICOSIA CYPRUS 14302M001 EPN class A, IGS
5 NOT1 NOTO ITALY 12717M004 EPN class A, IGS
2. Densification project2. Densification project
EPN stations
53th EUREF TWG Meeting, Gävle, June 1, 2010
5 NOT1 NOTO ITALY 12717M004 EPN class A, IGS
6 TRAB TRABZON TURKEY 20808M001 EPN class B, IGS
7 WTZR BAD KOETZTING GERMANY 14201M010 EPN class A, IGS
8 RAMO MITZPE RAMON ISRAEL 20703S001 EPN class A, IGS
9 ANKR ANKARA TURKEY 20805M002 EPN class A, IGS
10 GRAZ GRAZ AUSTRIA 11001M002 EPN class A, IGS
11 AUT1 THESSALONIKI GREECE 12619M002 EPN class A
12 NOA1 ATHENS GREECE 12620M001 EPN class A
13 TUC2 CHANIA GREECE 12617M003 EPN class A
14 ORID OHRID FYROM 15601M001 EPN class A, IGS
2. Densification project2. Densification project
HEPOS stations
Equipment Model IGS code
All HEPOS stations are equipped with the same GPS equipment
53th EUREF TWG Meeting, Gävle, June 1, 2010
Receivers Trimble NetRS TRIMBLE NETRS
Antennas Trimble Zephyr geodetic TRM41249.00
Domes Trimble spherical TZGD
2. Densification project2. Densification project
HEPOS stations
All HEPOS antennas are mounted on steel masts
On roof of buildings or On side of buildings
53th EUREF TWG Meeting, Gävle, June 1, 2010
2. Densification project2. Densification project
HEPOS stations
All HEPOS antennas are mounted on the frame of the building (reinforced concrete )
53th EUREF TWG Meeting, Gävle, June 1, 2010
2. Densification project2. Densification project
Observations used
14 days of observations (7-20 October 2007)
3 additional days (17-19 November 2007)
53th EUREF TWG Meeting, Gävle, June 1, 2010
3 additional days (17-19 November 2007) to include in the solution station 018B, which replaced station 018A.
3. Initial and recent solution3. Initial and recent solution
Initial solutionInitial solution
• Computed: December 2007
• ETRF2005 (current frame at that time)
• coordinates used for the HEPOS stations since HEPOS is operable
Recent solution Recent solution
53th EUREF TWG Meeting, Gävle, June 1, 2010
Recent solution Recent solution
• Computed: May 2010
• Follows the latest EUREF standards, i.e.:
• “Specifications for reference frame fixing in the analysis of a EUREF GPS
campaign” Ver. 7, 24/10/2008
• “Guidelines for EUREF Densifications”, Ver. 1, 26/05/2009
• ETRF2000
4. Initial solution4. Initial solution
4-char ID Country Network Comments
1 AUT1 GREECE EPN class A fiducial
2 ANKR TURKEY EPN class A, IGS validation point
3 GLSV UKRAINE EPN class A, IGS validation point
4 GRAZ AUSTRIA EPN class A, IGS validation point
5 JOZE POLAND EPN class A, IGS validation point
6 MATE ITALY EPN class A, IGS validation point
Fiducial and validation points
53th EUREF TWG Meeting, Gävle, June 1, 2010
6 MATE ITALY EPN class A, IGS validation point
7 NICO CYPRUS EPN class A, IGS validation point
8 NOA1 GREECE EPN class A validation point
9 NOT1 ITALY EPN class A, IGS validation point
10 ORID FYROM EPN class A, IGS validation point
11 RAMO ISRAEL EPN class A, IGS validation point
12 TRAB TURKEY EPN class B, IGS validation point
13 TUC2 GREECE EPN class A validation point
14 WTZR GERMANY EPN class A, IGS validation point
Note: At the time of computing the “HEPOS_initial” solution, there was no classification of
the EPN stations. The class given in this table refers to the status at the time of writing.
4. Initial solution4. Initial solution
Coordinates of fiducial points
Coordinates and velocities used for AUT1 (from EUREF site)
ITRF2005 2000.04466283.4880
± 0.0030
1896166.7750
± 0.0020
4126096.7730
± 0.0030
-0.0126
± 0.0005
0.0213
± 0.0002
0.0028
± 0.0005
53th EUREF TWG Meeting, Gävle, June 1, 2010
Computed Coordinates for AUT1 (at tc = 2007.79)
ITRF2005 2000.79 4466283. 3898 1896166. 9409 4126096. 7948
4. Initial solution4. Initial solution
Datum definition (ITRF2005)
Minimal constraints, i.e. by fixing the coordinates of AUT1.
AUT1 is used to compute transformation parameters from ITRF2005 to
ETRF2005. For this reason AUT1 is also used for constraining the solution in
ITRF2005.
53th EUREF TWG Meeting, Gävle, June 1, 2010
An important advantage of AUT1 is that it shows the smallest velocity among the
Greek EPN stations and could ensure maximum consistency between HTRS07
and ETRS89 in the northern part of Greece, i.e. on the borders between Greece
and the other European countries.
4. Initial solution4. Initial solution
Processing parameters
Software used
Bernese 5.0
Processing Agency
IGN-Spain *
53th EUREF TWG Meeting, Gävle, June 1, 2010
IGN-Spain *
* KTIMATOLOGIO S.A. procured the establishment of HEPOS as a turn-key solution including
the computation of the station coordinates. This task was assigned by the contractor (Trimble Europe B.V.) to IGN-Spain.
4. Initial solution4. Initial solution
Orbits and ERPs
IGS final orbit and ERP information
Antenna calibrations – stations
Absolute antenna phase center corrections based on IGS05 model
Processing parameters
53th EUREF TWG Meeting, Gävle, June 1, 2010
Absolute antenna phase center corrections based on IGS05 model
(exceptions for stations with individual absolute calibrations listed in
epnc_05.atx) considering antenna radome codes.
Antenna calibrations – satellites
Absolute antenna phase centre corrections based on IGS05 model
calibrations
4. Initial solution4. Initial solution
Processing parameters
Preprocessing
Phase preprocessing in a baseline by baseline mode using triple
differences. In most cases cycle slips are fixed looking simultaneously at
different linear combinations of L1 and L2. If a cycle slip cannot be fixed
53th EUREF TWG Meeting, Gävle, June 1, 2010
different linear combinations of L1 and L2. If a cycle slip cannot be fixed
reliably, bad data points are removed or new ambiguities are set up.
Basic Observable
Carrier phase, code only used for receiver clock synchronization.
4. Initial solution4. Initial solution
Processing parameters
Elevation angle cutoff
3 degrees + elevation dependent weighting with cos-z
Data sampling
For ambiguity resolution: 30 s.
53th EUREF TWG Meeting, Gävle, June 1, 2010
For ambiguity resolution: 30 s.
For final processing: 180 s.
Modeled observable
Double-differences, ionosphere-free linear combination.
Processing parameters
Troposphere
Dry-Niell as a priori model, estimation of zenith delay corrections at 1hour
intervals for each station, using the wet-Niell MF, no a priori sigmas.
Horizontal gradient parameter estimated/day/station (TILTING), no a
4. Initial solution4. Initial solution
53th EUREF TWG Meeting, Gävle, June 1, 2010
Horizontal gradient parameter estimated/day/station (TILTING), no a
priori constraints. Compute daily TRO files with fixed cumulative.
Coordinates input from weekly solution.
Ionosphere
Regional ionospheric model calculated. Only used for QIF ambiguity
resolution. Not modeled in final solution (ionosphere eliminated by forming
the ionosphere-free linear combination of L1 and L2).
4. Initial solution4. Initial solution
Estimated parameters
Adjustment
Weighted least-squares algorithms.
Rejection Criteria
Daily RINEX observation files containing less than 10 percent of possible
53th EUREF TWG Meeting, Gävle, June 1, 2010
Daily RINEX observation files containing less than 10 percent of possible
observation are ignored. The threshold value concerning data screening is
2.5 mm, specifically for a normalized, or L1 zero difference zenith residual.
Station where baseline data exceeding the overall sigma level of 5
millimeters is excluded.
4. Initial solution4. Initial solution
Estimated parameters
Troposphere
Absolute constraints: 5.0 m, Relative constraints: 5.0 m.
Ionosphere
Regional ionospheric model for QIF ambiguity resolution.
53th EUREF TWG Meeting, Gävle, June 1, 2010
Regional ionospheric model for QIF ambiguity resolution.
Ambiguity resolution
Ambiguity resolution is performed by using the quasi-ionosphere-free
(QIF) strategy with regional TEC information. Elevation angle cutoff: 10
degrees.
4. Initial solution4. Initial solution
Estimated parameters
Satellite clock bias
Satellite clock biases are not estimated but eliminated by forming double-
differences.
Receiver clock bias
53th EUREF TWG Meeting, Gävle, June 1, 2010
Receiver clock bias
Receiver clock corrections are estimated as part of the biases
preprocessing using code measurements. They are finally eliminated by
forming double differences.
4. Initial solution4. Initial solution
Estimated parameters
Planetary Ephemeris
DE200
Tidal effects
Solid earth tidal displacements are modeled according to IERS
53th EUREF TWG Meeting, Gävle, June 1, 2010
Solid earth tidal displacements are modeled according to IERS
conventions 1996.
Ocean loading
Using model computed by H.G.Scherneck Onsala Space Observatory
FES2004 model for each station.
Atmospheric loading
No atmospheric loading corrections are taken into account.
4. Initial solution4. Initial solution
Repeatabilities (North)
repeatabilities N (mm)
3
4
53th EUREF TWG Meeting, Gävle, June 1, 2010
0
1
2
AN
KR
MA
TE
RA
MO
00
2A
00
7A
01
2A
01
7A
02
1A
02
6A
03
1A
03
6A
04
1A
04
6A
05
1A
05
6A
06
1A
06
6A
07
1A
07
6A
08
1A
08
6A
09
1A
09
6A
4. Initial solution4. Initial solution
Repeatabilities (East)
repeatablities E (mm)
3
4
53th EUREF TWG Meeting, Gävle, June 1, 2010
0
1
2
AN
KR
MA
TE
RA
MO
00
2A
00
7A
01
2A
01
7A
02
1A
02
6A
03
1A
03
6A
04
1A
04
6A
05
1A
05
6A
06
1A
06
6A
07
1A
07
6A
08
1A
08
6A
09
1A
09
6A
4. Initial solution4. Initial solution
Repeatabilities (Up)
repeatabilities U (mm)
6
7
8
9
53th EUREF TWG Meeting, Gävle, June 1, 2010
0
1
2
3
4
5
6
AN
KR
MA
TE
RA
M
00
2A
00
7A
01
2A
01
7A
02
1A
02
6A
03
1A
03
6A
04
1A
04
6A
05
1A
05
6A
06
1A
06
6A
07
1A
07
6A
08
1A
08
6A
09
1A
09
6A
4. Initial solution4. Initial solution
Stn DX (mm) DY (mm) DZ (mm)
ANKR -1.7 -6.6 2.7
AUT1 1.7 -3.1 3.0
GLSV 6.0 -4.8 7.6
Stn North (mm) East (mm) Up (mm)
ANKR 5.0 -5.2 -2.4
AUT1 3.4 -3.2 2.0
GLSV 2.6 -7.4 6.9
In XYZ In NEU
Comparison of ITRF2005/2007.786 coordinates: initial solution vs. EUREF solution (EPN_A_ITRF2005_C1570)
53th EUREF TWG Meeting, Gävle, June 1, 2010
GLSV 6.0 -4.8 7.6
GRAZ 5.8 -2.3 4.2
JOZE 6.4 -3.3 5.5
MATE -0.4 -5.4 -0.3
NICO -2.6 -6.1 6.0
NOA1 -3.7 -7.4 -2.7
NOT1 -1.1 -4.0 -0.5
ORID 3.0 -4.3 -0.2
RAMO -8.1 -8.6 -1.5
TUC2 -2.2 -5.5 -1.1
WTZR 6.2 -2.5 4.3
GLSV 2.6 -7.4 6.9
GRAZ -0.5 -3.7 6.1
JOZE -0.8 -5.0 6.5
MATE 0.8 -4.8 -1.7
NICO 8.1 -3.8 -1.5
NOA1 2.1 -5.0 -6.8
NOT1 0.9 -3.6 -2.0
ORID -0.9 -5.2 0.1
RAMO 4.6 -2.6 -11.5
TUC2 1.2 -4.6 -4.0
WTZR -1.5 -3.9 7.4
4. Initial solution4. Initial solution
Transformation to ETRS89
At the time realization of HTRS07, version 6 of the B/A memo was valid.
53th EUREF TWG Meeting, Gävle, June 1, 2010
4. Initial solution4. Initial solution
Transformation to ETRS89
At the time of realization of HTRS07, no velocities were available for the HEPOS stations.
Furthermore, the velocity field in Greece is complex and inhomogeneous. The velocities of the Greek stations differ strongly among each other.
53th EUREF TWG Meeting, Gävle, June 1, 2010
Any application of individual velocities would distort the homogeneity of the HEPOS network.
For these reasons, no transformation to t = 1989.0 was done.
Note: According to the current version of the B/A memo (version 7) “it is no
longer recommended to propagate the station coordinates by means of
whatever intra plate velocities to other epoch than the central epoch tc of the
used”
� Use EUREF coordinates and velocities to compute ECEF coordinates of AUT1 in:
- ITRF05/2007.79 (central epoch for HEPOS network adjustment)
- ETRF05/2007.5 (central epoch of the HEPOS GPS campaign for the
computation of transformation model)
4. Initial solution4. Initial solution
Transformation to ETRS89
53th EUREF TWG Meeting, Gävle, June 1, 2010
computation of transformation model)
� Compute the translation components ∆Χ, ∆Υ and ∆Ζ between the above ECEF coordinates of AUT1
� Use of the above translation parameters to transform all HEPOS stations from ITRF05/2007.79 to ETRF05/2007.5.
4. Initial solution4. Initial solution
Transformation to ETRS89
Coordinates and velocities used for AUT 1 (from EUREF site)
ITRF2005 2000.04466283.4880
± 0.0030
1896166.7750
± 0.0020
4126096.7730
± 0.0030
-0.0126
± 0.0005
0.0213
± 0.0002
0.0028
± 0.0005
ETRF2005 2000.04466283.7370
± 0.0030
1896166.6250
± 0.0020
4126096.6180
± 0.0030
0.0049
± 0.0005
0.0033
± 0.0002
-0.0079
± 0.0005
53th EUREF TWG Meeting, Gävle, June 1, 2010
Resulting coordinates for AUT1 and transformation parameters
ITRF2005/2007.79 ETRF2005/2007.50 Translation parameters from ITRF2005/2007.79 to ETRF2005/2007.50*
X = 4466283. 3898 X = 4466283.7737 DX = 0.3839
Y = 1896166. 9409 Y = 1896166.6497 DY = -0.2912
Z = 4126096. 7948 Z = 4126096.5587 DZ = -0.2361
* Epoch 2007.500 was chosen, as it was the central epoch of the national GPS campaign carried-out
for the computation of a transformation model between HTRS07 and the National coordinate system HGRS87
Fiducial points
5. Recent solution5. Recent solution
4-char ID Country Network Comment
1 AUT1 GREECE EPN class A In the densification zone
2 ANKR TURKEY EPN class A, IGS
3 GLSV UKRAINE EPN class A, IGS
4 GRAZ AUSTRIA EPN class A, IGS
5 JOZE POLAND EPN class A, IGS
53th EUREF TWG Meeting, Gävle, June 1, 2010
5 JOZE POLAND EPN class A, IGS
6 MATE ITALY EPN class A, IGS
7 NICO CYPRUS EPN class A, IGS
8 NOT1 ITALY EPN class A, IGS
9 NOA1 GREECE EPN class A In the densification zone
10 ORID FYROM EPN class A, IGS
11 RAMO ISRAEL EPN class A, IGS
12 TUC2 GREECE EPN class A In the densification zone
13 WTZR GERMANY EPN class A, IGS
5. Recent solution5. Recent solution
Coordinates of fiducial points
Stn
Data Start - Data End
DOY/year - DOY/year X Y Z Vx Vy Vz X Y Z
ANKR 309/2006 - 131/2008 4121948.539 2652187.914 4069023.767 -0.0080 -0.0045 0.0084 4121948.5164 2652187.9013 4069023.7908
Computed coordinates at tc = 2007.83Coordinates and velocities at to = 2005.00 (EPN_A_ITRF2005_C1570)
The ITRF2005/2007.83 coordinates of the fiducial points were computed using solution C1570.
53th EUREF TWG Meeting, Gävle, June 1, 2010
AUT1 309/2006 - 044/2010 4466283.433 1896166.881 4126096.790 -0.0149 0.0204 0.0028 4466283.3908 1896166.9387 4126096.7979
GLSV 309/2006 - 312/2007 3512888.957 2068979.880 4888903.212 -0.0190 0.0141 0.0091 3512888.9032 2068979.9199 4888903.2378
GRAZ 309/2006 - 044/2010 4194423.823 1162702.697 4647245.416 -0.0167 0.0176 0.0108 4194423.7757 1162702.7468 4647245.4466
JOZE 309/2006 - 044/2010 3664940.167 1409153.865 5009571.389 -0.0173 0.0153 0.0098 3664940.1180 1409153.9083 5009571.4167
MATE 309/2006 - 334/2008 4641949.555 1393045.429 4133287.461 -0.0176 0.0189 0.0155 4641949.5052 1393045.4825 4133287.5049
NICO 077/2007 - 044/2010 4359415.718 2874117.073 3650777.826 -0.0193 0.0105 0.0123 4359415.6634 2874117.1027 3650777.8608
NOA1 309/2006 - 044/2010 4599641.930 2034827.315 3909890.640 0.0030 0.0093 -0.0094 4599641.9385 2034827.3413 3909890.6134
NOT1 309/2006 - 044/2010 4934546.229 1321265.012 3806456.119 -0.0186 0.0169 0.0150 4934546.1764 1321265.0598 3806456.1615
ORID 212/2000 - 293/2007 4498451.692 1708266.984 4173591.865 -0.0149 0.0202 0.0095 4498451.6498 1708267.0412 4173591.8919
RAMO 309/2006 - 044/2010 4514721.846 3133507.840 3228024.701 -0.0210 0.0131 0.0181 4514721.7866 3133507.8771 3228024.7522
TRAB 345/2006 - 331/2007 n/a n/a n/a n/a n/a n/a - - -
TUC2 309/2006 - 044/2010 4744543.776 2119411.896 3686258.843 0.0027 0.0098 -0.0103 4744543.7836 2119411.9237 3686258.8139
WTZR 309/2006 - 024/2009 4075580.558 931853.799 4801568.139 -0.0156 0.0168 0.0103 4075580.5139 931853.8465 4801568.1681
5. Recent solution5. Recent solution
Datum definition (ITRF2005)
Using minimal constraints, to compute three translation parameters on the network´s barycentre.
This strategy has the advantage that small errors in the coordinates do
53th EUREF TWG Meeting, Gävle, June 1, 2010
This strategy has the advantage that small errors in the coordinates do
neither distort the network geometry nor significantly degrade the datum
definition per se.
5. Recent solution5. Recent solution
Processing parameters
The processing parameters and the repeatabilities are the same like in the Initial solution.
53th EUREF TWG Meeting, Gävle, June 1, 2010
in the Initial solution.
5. Recent solution5. Recent solution
Comparison of ITRF2005/2007.83 coordinates: recent solution vs. EUREF solution (EPN_A_ITRF2005_C1570)
In XYZ In NEU
Stn North (mm) East (mm) Up (mm)
ANKR 2.8 -0.2 -1.8
AUT1 -0.2 2.0 3.0
GLSV 0.4 -1.8 7.2
Stn DX (mm) DY (mm) DZ (mm)
ANKR -2.6 -1.8 1.2
AUT1 1.3 2.9 1.9
GLSV 4.5 0.8 5.9
53th EUREF TWG Meeting, Gävle, June 1, 2010
GLSV 0.4 -1.8 7.2
GRAZ -2.0 2.0 5.0
JOZE -2.0 0.2 5.8
MATE -0.2 0.6 -2.8
NICO 5.8 1.6 -0.6
NOT1 -0.4 2.2 -3.4
NOA1 -1.0 0.0 -6.8
ORID -2.8 0.6 0.2
RAMO 2.6 3.0 -9.2
TUC2 -1.2 1.0 -4.0
WTZR -2.4 1.8 5.0
GLSV 4.5 0.8 5.9
GRAZ 4.0 3.3 2.4
JOZE 4.5 2.1 3.3
MATE -2.2 0.2 -1.9
NICO -4.1 -0.7 4.6
NOT1 -4.3 -2.0 -5.1
NOA1 -3.0 1.5 -2.2
ORID 1.5 1.5 -1.9
RAMO -9.4 -2.8 -2.4
TUC2 -2.7 -0.2 -3.4
WTZR 4.4 3.0 2.3
Transformation to ETRS89
5. Recent solution5. Recent solution
The transformation of the ITRF2005/2007.83 coordinates to ETRF2000/2007.83 was done using the EPN web page tool.
53th EUREF TWG Meeting, Gävle, June 1, 2010
ETRF2000/2007.83 was done using the EPN web page tool.
6. Comparison of initial and recent solution6. Comparison of initial and recent solution
Comparison of ETRS89 coordinates: Initial solution vs. recent solution
2
4
D North (mm)
53th EUREF TWG Meeting, Gävle, June 1, 2010
-14
-12
-10
-8
-6
-4
-2
0
2
001A
006A
011A
016A
020A
025A
030A
035A
040A
045A
050A
055A
060A
065A
070A
075A
080A
085A
090A
095A
6. Comparison of initial and recent solution6. Comparison of initial and recent solution
Comparison of ETRS89 coordinates: Initial solution vs. recent solution
D East (mm)
-4-202
53th EUREF TWG Meeting, Gävle, June 1, 2010
-28-26-24-22-20-18-16-14-12-10-8-6-4
001A
006A
011A
016A
020A
025A
030A
035A
040A
045A
050A
055A
060A
065A
070A
075A
080A
085A
090A
095A
6. Comparison of initial and recent solution6. Comparison of initial and recent solution
Comparison of ETRS89 coordinates: Initial solution vs. recent solution
D Up (mm)
0
10
53th EUREF TWG Meeting, Gävle, June 1, 2010
-40
-30
-20
-10
0
001A
006A
011A
016A
020A
025A
030A
035A
040A
045A
050A
055A
060A
065A
070A
075A
080A
085A
090A
095A
6. Comparison of initial and recent solution6. Comparison of initial and recent solution
Comparison of ETRS89 coordinates: Initial solution vs. recent solution
Statistics
DN (mm) DE (mm) DS (mm) DU (mm)
Max |D| 13.4 26.0 27.4 39.8
53th EUREF TWG Meeting, Gävle, June 1, 2010
Max |D| 13.4 26.0 27.4 39.8
Mean D - 4.7 - 17.5 - 19.4
Mean |D| 5.2 17.5 18.5 19.9
Conclusion: The two solutions are consistent to a few centimeters: • Maximum differences do not exceed 3 cm (horizontal) and 4 cm (vertical). • Mean differences are below 2 cm both in the horizontal and in the vertical component.
IGN-Spain for the computation of the HEPOS network.
Prof. K. Katsampalos and C. Kotsakis (AUTH: Aristotle University of Thessaloniki) for assisting KTIMATOLOGIO SA in the definition HTRS07 and the computation of coordinate transformation model.
The chair and the members of EUREF-TWG for their valuable
Acknowledgments Acknowledgments
53th EUREF TWG Meeting, Gävle, June 1, 2010
The HEPOS project is part of the Operational Program “Information Society” and is co-funded by the European Regional Development Fund.
The chair and the members of EUREF-TWG for their valuable comments in the preparation of the report.