NTRIP and Mountpoints

How to Log-in to the NTRIP caster for real-time corrections

Registered users with active Subscriptions will be able to log in to the C4Gnet.XYZ NTRIP caster and receive real-time corrections for their field rovers using the following information in their NTRIP client settings: 

Host Address: C4Gnet.XYZ 

Port Address: 9000 

Once connected to the NTRIP caster your rover can request a list of available mountpoints. 

What are Mountpoints? 

A mountpoint defines the type of processor used, what satellite constellations are supported, the format of the correction messages and the reference frame that relates to a real-time data stream. When connecting to the C4Gnet Real Time Network, a mountpoint list is generated from which a user selects the desired mountpoint. If a mountpoint is hard coded in a rover setup the mountpoint list will not be displayed.

NOTE: All mountpoints except the legacy ones use this naming structure: 

Also Note: The Legacy mountpoint names are obsolete!  

Since legacy mountpoints like GLN_RTCM3_2, GLN_CMRx and GLN_NetDGPS do not follow the new naming convention, it was hard to know what is being provided in their solutions. Therefore, some have been removed from the mountpoint list already and others will be removed soon.  

If you currently use a legacy mountpoint, you must change to one of the new mountpoints using the new naming convention. While legacy mountpoints will work for a short while the same as the new ones, you will have to figure out what each one contains after connecting to it and since it will be removed soon, we recommend that you do not use them anymore and move to a new mountpoints ASAP. 

New Mountpoint Naming Convention uses 4 Groupings:  


Each character grouping is separated by an under bar before the next set of characters. 

1.  The first set of characters is the SOLUTION TYPE. VRS, PPP or NSB are the current processing methods that you can choose:  
VRS or Virtual Reference Station: Uses a Network RTK Processor to create a Virtual Reference Station and applies network corrections in RTK accuracy from the parent processor to the receiver data. 
PPP or Precise Point Positioning: Uses a Network RTXNet Processor to create a Virtual Reference Station and applies network corrections in RTK accuracy from the parent processor to the receiver data. 
NSB or Nearest Single Base: Selects the nearest suitably operating reference station using the position reported by the rover and propagates that receiver’s observation data to the rover. 

2.  The second set of characters points out the SATELLITES ;  
GPS: Mountpoints with GPS in the name use GPS satellite vehicles only. 
GNSS: Mountpoints with GNSS in the name use both GPS and GLONASS SVs in the solutions. 
GREC: Mountpoints with GREC in the name include 4 satellite constellations, which include Galileo, BeiDou, GPS and GLONASS Satellite Vehicles in their solutions. Mountpoints with GREC in the name only appear in mountpoints in the CMRx or RTCM3_2 format that use the PPP or NSB processing methods.  

3.  The next set of characters define the MESSAGE FORMAT.  

The following explains each available format: 

CMRx This is the latest Trimble proprietary format for Network RTK mountpoints: CMRx allows Real-Time Kinematic (RTK) users to use more satellite constellations and signals as they become available, with faster initializations and improved performance near obstructions and under canopies. It offers significant compression (around 40%) over the already compact CMR/CMR+ format to help users receive corrections within less bandwidth. Trimble rovers that support CMRx should use it exclusively.

RTCM 3.2 Carrier and Code Differential Corrections for High-Precision RTK, Network RTK, and PPP-type applications. Recently modernized with so-called Multiple Signals Messages (MSM), for generic inclusion of new constellations and signals. MSM Currently supports GPS, GLONASS, Galileo, QZSS, BeiDou, SBAS.

CMRp Network RTK mountpoint (e.g., CMRp_All): This is intended for legacy equipment in industry groups where CMR plus has been used as a quasi-standard format (such as precision agriculture). CMR plus is a Trimble format so non-Trimble users are advised to use the RTCM 3.x format unless you are sure your device fully supports CMR+.

RTCM 3.1 Network RTK mountpoint (e.g., GLN_RTCM3_1): This format supports both GPS and GLONASS SV’s and will supply a network RTK data stream optimized for the user’s location.

DGPS Virtual Base mountpoint (e.g., NetDGPS): This will supply a sub-meter differential solution optimized for the user’s location.

4.  The fourth and last set of characters is the REFERENCE FRAME e.g.: NAD83 and ITRF2014 

         NAD83 and ITRF2014 are different reference frames, and we call them out in the mountpoint name so that users may tell them apart by simply looking at the mountpoint names. C4Gnet.XYZ can support any reference frame users need to work in so if or when we get requests for additional reference frames or when a new datum is published by National Geodetic Survey (NGS), we can add these and make them easy to select by looking at the reference frame being used at the end of each mountpoint name.

Recommended Survey Mountpoints: 

· Trimble Rovers – PPP_GREC_CMRx_NAD83 

· Other Rovers – PPP_GREC_RTCM3_2_NAD83 

NOTE: We encourage you to try other mountpoints if you are not getting the expected precisions or number of SV’s.