When you are going to use the data as reference station you will need accurate coordinates for the station marker, at the epoch of measurement, and in a well defined reference frame. The coordinates given in the RINEX headers are only approximate coordinates and should not be used, except for selection and plotting purposes. When it comes to coordinates there is not a single solution.
First, you have to decide for which reference system and reference frame you want to have coordinates for. There are broadly two options: a global or a regional reference frame.
The International Terrestrial Reference System (ITRS) provides a global reference frame (ITRF). Station coordinates in the International Terrestrial Reference Frame (ITRF) at the epoch of measurement can be computed as follows
X(t) = X(t0) + V(t0) * (t - t0)with X(t0) and V(t0) the ITRF coordinates and velocities at the reference epoch t0. Velocities, which are of the order of a few centimeter per year, are the result of tectonic plate motion. Different realizations of ITRF are available, indicated by ITRF<year>, with slightly different coordinates and velocities. This is because of continuous improvements in the realization of the reference frame and new measurements that become available. The most recent realization of ITRS is ITRF2014 and IGS14, which is a special variant ITRF2014 that is used for GNSS.
When you are looking for coordinates that don't change much over time the solution you probably want to use a regional reference frame. For Europe this is the European Terrestrial Reference System 1989 (ETRS89). ETRS89 moves along with the Eurasian tectonic plate. Velocities in ETRS89 are therefore much smaller than velocities in ITRF (often less than a few millimeters per year) and are only due to intra-plate motion and autonomous station motion. For most applications velocities in ETRS89 can be neglected. Coordinates in ETRS89 are also improved on a continuous basis, due to improvements in the measurement and analysis techniques, the underlying models that are used, and growing amount of data. These improvements are captured in different realizations (releases) of ETRS89, such as ETRF2000 and ETRF2014.
Coordinates and velocities in ETRS89 (ETRF2000, ETRF2014) and ITRS (ITRF2000, IGS14) can be found on the EUREF Permanent Network (EPN) website Positions & Velocities page:
DELF, DLF1, EIJS, IJMU, KOSG, KOS1, TERS, VLIS, WSRT.Please note that positions and velocities are only available for stations that are processed by IGS and EPN analysis centers. Solutions for more ITRF reference frames can be found at the ITRF solutions website.
The Dutch Kadaster provides official coordinates, in ETRF2000(R05) at epoch 2010.5, for all AGRS.NL stations. These are the coordinates that should be used for land surveying activities in the Netherlands. These are also the coordinates that are used in the RTCM data streams. The coordinates in ETRF2000(R05), at epoch 2010.5, are
STATION NAME X (M) Y (M) Z (M) AMEL 13540M001 3787664.3131 382392.2606 5100339.6132 APEL 13510M001 3895237.0713 406814.3176 5017378.0589 DELF 13502M004 3924687.7018 301132.7660 5001910.7746 DLF1 13502M009 3924698.1158 301124.8036 5001904.9952 EIJS 13533M001 4023086.5325 400394.8618 4916655.3315 IJMU 13537M001 3882053.2726 309346.2061 5034330.2263 KOS1 13504M005 3899613.9607 397361.6230 5014738.6348 SCHI 13541M001 3782171.4282 408355.7860 5102376.9334 TERS 13534M001 3798580.8745 346993.8452 5094780.8097 TXE2 13542M001 3829292.8723 324999.2444 5073333.5276 VLIE 13539M001 3805256.1488 339064.9340 5090357.9072 VLIS 13538M001 3975805.2237 249950.0825 4964446.0875 WSRA 13506M005 3828736.1381 443304.7367 5064884.5110 WSRT 13506M005 3828736.1381 443304.7367 5064884.5110These coordinates have been computed using a multi year time series analysis solution. If you need coordinates in ITRF then you can use the EPN ETRF/ITRF transformation service.
Stations that have been realized recently, for example the IGRS stations in CBW1, ZEGV and ROVN, are not available from the multi-year solutions. For these stations, provisional coordinates in ETRS2000, are
STATION NAME X (M) Y (M) Z (M) CBW1 13536M001 3923113.3483 338135.2474 5000752.2147 ZEGV 13543M001 3908910.3663 330932.7742 5012262.5786 ROVN 13544M001 3859571.8076 413007.6749 5044091.5729These coordinates have been computed using the Kadaster certification procedure (CBW1) or by a multi-day PPP solution (ZEGV).
If you need coordinates for stations not listed in one of these resources you can always compute the coordinates on-line using on of the available web-based PPP processing services.
In case you want coordinates in WGS84 then it becomes a bit tricky. Although WGS84 is alligned with ITRF at the decimeter level, it is not identical to any of the afore mentioned reference frames. Often, WGS84 is used as an encompassing term for ITRF or ETRS89, which is certainly okay at the meter level accuracy, but not specific enough for the centimeter and decimeter type of applications. Should you ever be in doubt about which reference frame to use, and your area of interest is the Netherlands, then most likely it is ETRF2000 and you should use the coordinates published by the Dutch Kadaster. If this is not the case, and you are using data from more than one station, please make sure that all coordinates refer to the same reference frame.
The in the previous section mentioned resources also provide velocities. An other resource for station velocities is the Nevada Geodetic Laboratory, and velocities computed by Jet Propulsion Laboratory (JPL), both in the IGS08 (ITRF2008) reference frame.
The Dutch Kadaster computes velocities for AGRS.NL stations in the ETRF2000(R05) reference frame:
STATION NORTH EAST UP [MM/YEAR] AMEL +0.3 +0.4 -2.4 APEL -0.2 -0.8 -0.4 DELF -0.2 -0.6 -0.2 DLF1 +0.1 +0.1 -2.2 EIJS -0.0 -0.8 +1.1 IJMU -0.1 -0.2 -0.9 KOS1 +0.3 -0.2 -2.6 SCHI -0.6 -0.2 -3.0 TERS -1.3 +0.3 -0.0 TXE2 -0.1 -0.1 -1.8 VLIE -0.8 -0.4 -3.9 VLIS -0.7 +0.4 -0.1 WSRA +0.6 -0.6 -0.1 WSRT +0.6 -0.6 -0.1
Station time series are available for various resources:
For more information or questions contact Hans van der Marel.