****************************************************************************** EUREF Electronic Mail 29-Aug-2012 11:30:08 UTC Message Number 6566 ****************************************************************************** Author: EPN CB/C.Bruyninx Subject: NULLANTENNA option not allowed for EPN RTCM streams Dear Colleagues, When generating an RTCM stream, the station operator has the possibility to use the option NULLANTENNA (or ADVNULLANTENNA or GPPNULLANTENNA). Please not use this option! Activating this option means that the receiver will change the observations in the RTCM stream by applying some antenna calibration values so that the observations are not referring any more to the antenna phase centre (as expected by the RINEX convention), but to the antenna reference point. As a result, we can get position errors between 5-10 cm when using the RTCM streams of these stations because during the analysis the antenna phase centre model is applied again (in addition to the correction at the observation level done in the receiver). So, if the NULLANTENNA option is activated at a station, the observations are changed and corrected by an antenna calibration model. The problem is that: - we do not know which antenna model is used - we have no means to identify stations who activated this option once the RTCM data have been converted to RINEX In practice, this option could be useful for RTK reference stations, because then the RTK-user does not have to deal with any antenna model for the RTK reference stations. But, as you can imagine, for EPN streams, the option NULLANTENNA cannot be accepted. I ask all operators of EPN stations streaming RTCM data to EUREF to carefully check the options for the generation of their RTCM streams. We could already identify the following stations which are using the NULLANTENNA option: BRST0, CASC0, FLRS0, FUNC0, GAIA0, GANP0, LAGO0, and PDEL0 as indicated in ftp://epncb.oma.be/pub/station/real_time/monitor.ant I urge these station managers to de-activate this option! In case some of the affected stations are part of a network serving RTK users, then please contact epncb@oma.be and euref-ip@bkg.bund.de in order to discuss possible options without affecting the RTK users. Thank you for your consideration, Carine EPN Central Bureau PS: I realize that some stations have been sending data with the NULLANTENNA option since a very long time. However, it is just recently that we realized the implications of this option. ----------------------------------------------------------------- Carine Bruyninx Email : C.Bruyninx@oma.be Royal Observatory of Belgium Phone : +32-(0)2-3730292 Av. Circulaire 3 Fax : +32-(0)2-3749822 B-1180 Brussels BELGIUM ----------------------------------------------------------------- [Mailed from: Carine Bruyninx ] EUREF Mailing list maintained by epncb@oma.be and archived at ftp://epncb.oma.be/epncb/mail/ and http://epncb.oma.be/_newsmails/EUREFmail/