With the release of Leica System 1200 Firmware version 5.50, Leica Geosystems products now support GLONASS observations in the CMR / CMR+ RTK formats.
The majority of real-time kinematic system manufacturers implement proprietary data formats and protocols to distribute reference station data to the rover. The Compact Measurement Record format (CMR) was first published by Trimble in 1996 to provide a low bandwidth alternative to existing RTCM (Radio Technical Commission for Maritime Services) standards. Trimble’s GLONASS observation extension to the CMR / CMR+ format is proprietary and has not been published yet.
With Leica System 1200 Firmware version 5.50 the RTK format CMR / CMR+ now includes support of GLONASS observations. These new Leica CMR / CMR+ compatible massages that include GLONASS observations are published in the attached document.
When GLONASS observations are broadcast via CMR / CMR+ from receivers manufactured by Topcon or NovAtel, Leica Geosystems receivers consider both GPS and GLONASS observations. In the case where GLONASS observations are broadcast from Trimble CMR RTK networks and receivers the Leica Geosystems receivers consider only the GPS observations for a phase fixed solution.
Nevertheless, to follow an international standard that is agreed amongst all manufacturers and highly compact, it is recommended to use RTCM v3.x for transmission of GPS and GLONASS reference observations. In particular when receiver types are being mixed on the reference and rover side, RTCM v3.x should be configured.
