SNIP users can relay data from a remote caster by establishing a TCP/IP connection using the controls on the Relay Tab.  This guide contains the necessary steps for adding a relayed caster stream in SNIP.  A relay-remote stream is when your copy of SNIP acts like an NTRIP Client and connects to another (remote) NTRIP Caster and then relays that data to your users (along with your other streams of data).

The following information is necessary to set up a relayed caster stream:

1. Host URL and port number of the remote caster
2. Access information to the remote caster (user name and password, when required)
3. Latitude and longitude (if the target is a virtual reference station)
4. Various settings used to instruct SNIP on how to process and handle the stream (i.e parsing)

Getting started

A fresh installation of SNIP will have three default relayed streams running on start up as shown in the image below:

These streams, all taken from our open caster, are installed with any fresh installation simply to show the tool working. Of course, you will install whatever streams meet your own local needs.

A user is free to add,  remove, or edit existing streams, up to the number of simultaneous connections allowed by his license.  To add a new stream, click on the “Add New Stream…” button underneath the table.  A dialog will prompt the user to fill out the necessary caster details.  Alternatively, right click on any stream in the table to open a context menu for additional controls.

The relayed caster dialog

When a user decides to create a new relayed stream or edit an existing one, the below dialog will appear for the user to input the caster’s detail.  There are three ways to fill out the dialog:

1. Retrieve a previously stored configuration to fill out the dialog automatically.
   (You can store and edit favorite caster configurations to rapidly change the casters you are using)
2. Fill out the caster details with a known caster
   (SNIP will recall your prior caster connections and account passwords), then complete the rest manually.
3. Fill out the entire dialog manually if the user has all the necessary detail.
   (Used when Connecting to another NTRIP Caster for the very first time)

In the above example the user has selected the known caster “ntrip.itsware.net” which populated the host, port and user details, and then automatically returned the current set of mount point for that Caster.  The first entry (AZU1…) was selected and a configuration name was automatically developed from this in case the user wanted to save it. The default values are to parse the RTCM3 stream and the log the data file, but these can be changed as required.

If desired, user can save these parameters as a named configuration for future usage. The description text box allow a short memo describing the salient features of this setup.  The configuration name is auto generated based on the mountPt string but can be changed to suit.

Hint:  Configurations are a powerful tool to capture all of the setup details for a stream.  When a Configurations is selected (at the top of the dialog) it values are written into the reset of a dialog controls.  When the element in this dialog are written into the slot being edited, it is not longer connect to the Configuration that may have created it.  Said another way, changes to the slot’s settings, do not copy back to the Configuration that created it.

Once the necessary information is filled out, by clicking the “OK” button, SNIP will create a new relayed stream and attempt to connect.

The status of the new stream will be displayed in the new column in the table (the right most column in the above image).  As the stream comes on line, it will be correctly entered into the Caster table for Clients to learn about it and to connect to it.  The operator can now view details about the desired data stream by using controls from the table and the right-click context menu.

Tip: But I have several older TCP/IP Base Station, not a remote Caster…

In this case there is not any NTRIP layer present, but you can use the above method to connect to this type of  stream anyway.

Many useful but older base stations (~10 years of more) which were developed before NTRIP became widespread have this issue.  And some GNSS vendors want a pretty penny to install NTRIP Server software on them after the fact, if it is supported at all.   Some users are motivated by the cost saving that SNIP provides in this regard.  These older devices operate with only a TCP/IP layer.  All parties that connect to them will get the single stream they provide.

When SNIP connects to such a device, it first sends the correct NTRIP protocol details, which are simply ignored, and then the base stations data is returned.   In this case the mountPt string which you enter is not used by the base station (as it only can provide the one data stream), but that value is used by SNIP. This is how you assign a name to the resulting mountPt for your users.