1. Permanent GPS Stations in Israel as Basis for
Updated Geodetic Network
Gilad Even-Tzur
Faculty of Civil and Environmental Engineering
Mapping and Geo-Information Engineering
Technion, Haifa 32000, Israel
Moshe Rozenblum, Einat Salomon
Survey of Israel
1 Lincoln St. Tel-Aviv 65220, Israel

2. Permanent GPS Stations in Israel, Sept. 2005
SLOM
YRCM
AREL
DSEA
NRIF
 17 Stations
Receivers: 11 Ashtech Z-XII
5 Leica SR530
1 Trimble 5700
Antennas: 9 Ashtech DM
5 Leica DM
2 Topcon CR4
1 Trimble DM

3. Permanent GPS stations in Israel, Sept. 2005
SLOM
YRCM
AREL
DSEA
NRIF
 10 stations are situated on stable roof tops
NRIF

4. Permanent GPS Stations in Israel, Sept. 2005
 7 stations have geodynamic monuments
SLOM
YRCM
AREL
DSEA
NRIF
LHAV

5. The Control Center
The GPS receivers are connected to a control center, equipped with master and backup servers, through frame relay connections.

6. The Communication Network

7. The GPS Data Flow  5 sec sampling rate
SLOM
YRCM
AREL
DSEA
NRIF
 5 sec sampling rate
 Data is downloaded in real time
 The RINEX data is gathered into 1-hour interval files and posted on the internet

8. Operation Manager Software
The network is controlled by the RTD software.
It is based on epoch-by-epoch technology, which enables monitoring any changes in the station coordinates due to deformation and lost qualities.

9. Permanent GPS Stations in Israel, Sept. 2005
 RAMO is the official IGS station in Israel
 The data is processed at SOPAC
 The data from RAMO and DRAG is also processed at GIBS (GPS-Informations- und Beobachtungssystem )
SLOM
YRCM
AREL
DSEA
NRIF

10. The Permanent GPS Stations in Israel are called: APN
Active Permanent Network
SLOM
YRCM
AREL
DSEA
NRIF
Free 30 sec sampling rate data is available at:
ftp://

11. The APN Network
SLOM
YRCM
AREL
DSEA
NRIF
Until recently, the APN network was mainly used for geodetic and geophysical research.
The APN was used less for surveying purposes:
- Short sessions
- OTF ambiguity resolution used
- Lack of transformation between WGS84 and ITM

12. VRS - Virtual Reference Station
Economically and practically, there is no need to increase the number of permanent GPS stations in Israel.
In order to enable GPS surveying over the entire state of Israel with direct connection to the permanent GPS network, VRS technology is applied.
The VRS is produced by the GEO++ software

13. User Interface for Receiving Data

14. Advantages of Using the APN
Uniformity
Accuracy
Reliability
Simplicity
► In the near future an RTK option will be added to the APN network

15. Datum Definition
► Geodetic datum is a set of parameters and control points used to:
● Define the size and shape of the earth.
● Define the origin and orientation of the coordinate systems used to map the earth.
► Geodetic datums range from flat-earth models used for plane surveying to complex models used for international applications.
► The datum is the basis for a plane-coordinate system.

16. Datum Definition (continuance)
► GPS positions and vectors are referenced in the WGS-84 datum
► The Israeli coordinate system is referenced in the GRS-80 reference ellipsoid with geodetic projection called:
ITM - Israel Transverse Mercator

17. Datum Transformation
Transformation parameters describe the relations between two different datum systems.
7 Parameter transformation:
Shifts
Scale
Rotations

18. Datum Transformation (continuance)
The set of transformation parameters is determined by a least-squares solution:

19. The Plane Coordinates of the APN Points
► Each point from the APN network was connected by GPS observations to the nearest 1st order control points.
► A local datum transformation was calculated in order to assign plane coordinates to each permanent GPS station.
The accuracy of the coordinates is equivalent to the accuracy of the classical 1st order control network (~10cm)

20. Permanent GPS Network
A permanent GPS-based network is obviously more accurate, reliable and homogenous than a classical network.
Permanent GPS Network
Supreme Network

21. New Datum for APN
A set of coordinates that was valid for GPS day 275 of the year 2004 (October 1st , 2004) in the ITRF2000 coordinate system was set as the fixed coordinates set for the permanent GPS stations
This set of coordinates defined a new datum for APN, called
IGD05
Israel Geodetic Datum 2005

22. 5cm
50km
Scale
Network:
Residual:
Horizontal residuals resulting from the seven parameters transformation between the ITRF2000 (IGD05) datum and the Israel Grid datum

23. New Datum for Israel Grid
A new set of plane coordinates were adopted for the APN points.
The new coordinates defined actually new datum for the Israeli Grid called:
IG05
Israel Grid 2005
The adopted plane coordinates is a result of similarity transformation between two datums (IGD05 and IG05) which supplied practically zero residuals in the least-squares process.

24. Official 7 Parameters Transformation
IGD05
IG05
Calculate official 7 parameter transformation between the two systems

25. A flow chart for calculating new control points in IG05 coordinate system

26. Measuring methods for establish
new control point
1. Relative to APN station
2. Relative to VRS
3. Relative to base station
4. Geodetic network

27. Field Work Guidelines
► Two independent Observation sessions
► Observation sessions of at least 10 min
► Time duration between two sessions of at least 60 min

28. 1. Measuring relative to APN station
First session:
10min
10min
10min
10km
TELA
10min

29. Time duration between sessions – 60 min
1. Measuring relative to APN station
Second session:
10min
10min
TELA
10min
Time duration between sessions – 60 min

30. 2. Measuring relative to VRS
First session:
10min
5km
10min
10min
VRS1
10min

31. 2. Measuring relative to VRS
Second session:
10min
10min
VRS1
10min
VRS2
VRS3
Time duration between sessions – 60 min
The distance between two VRS should be at least 120m

32. 2. Measuring relative to VRS
Measured vectors:
VRS2
VRS1
VRS3

33. 3. Measuring relative to base station
IGD05
► Connect the base station to IGD05 system
10km
90min
BASE
IGD05

34. 3. Measuring relative to base station
IGD05
► Measuring new control points
First Session:
10min
10min
10min
BASE
10min
IGD05

35. Time duration between sessions – 60 min
3. Measuring relative to base station
ILGD05
► Measuring new control points
Second Session:
10min
10min
BASE
10min
ILGD05
Time duration between sessions – 60 min

36. 4. Measuring Geodetic Network
Assume work with 3 receivers
IGD05 1
Sessions of at least 10 min
Each new point should be measured in two independent sessions 2 3 4
IGD05

37. The Geodetic-Geodynamic Network (G1)
► Includes 160 points that homogeneously cover the state of Israel
► The location of the points was determined mainly according to geological considerations
► The points were built according to very high technical specifications, to ensure their geotechnical stability

38. The goal of the Geodetic-Geodynamic Network
► A potential geodetic network for monitoring deformations in primary and secondary known faults
► Serves as the major geodetic control network of Israel

39. The Measurement Campaigns
► During 1996 the G1 network was measured for the first time (Blue circles and Red squares)
► The second campaign was held in 2002
► Only 100 points were measured (Blue circles)
► 5 new points were fixed in the northern part of the network (Yellow circles )
► 11 continuous permanent GPS stations were operated (Green triangles)
► the accuracy of the points is better than 1cm

40. The G2 Network ► Abut 1000 points that organized in closed loops
► Most of the points are BMs from the Israeli vertical control network
► The points were measured during long period and not as one campaign
► The network accuracy is not homogeneous and not satisfactory (~5cm)

41. Vertical Control
► Survey of Israel (SOI) decided that the future vertical control in Israel will be based on ellipsoidal heights instead of orthometric heights
► SOI will support and maintain spatial geodetic network which will serve as horizontal and vertical control
► The APN and G1 will be used as basis for ellipsoidal vertical control
► Undulation model will be used to convert ellipsoidal heights to orthometric heights